Computer History Wiki - User contributions [en]

RK11 disk controller

2024-09-26T16:52:19Z

Glitch: /* RKV11-D */ adding picture of RKV11-D and H780 removed from mounting box, description of mounting

The '''RK11''' and '''RKV11''' series of controllers for the [[UNIBUS]] and [[QBUS]] are for the earlier RK moving-[[head]] [[magnetic storage|magnetic]] [[disk]] [[drive]]s ([[RK02/03 disk drive|RK02]]-[[RK05 disk drive|RK05]]), all based on the [[IBM 2315]] drive and pack.

(The later [[RK06/07 disk drive|RK06 and RK07]], and their controller, the [[RK611]], are a different and entirely incompatible drive and pack.)

There are several models of the RK11, which are basically identical in their programming interface; differences between them are discussed in the sections on the individual models (below).

The UNIBUS RK11's all connect to the RK drive(s) through a [[bus]] carried over a [[BC11A]] cable, the standard UNIBUS cable.

==Early RK11 version==

Although the [[RK11-C disk controller|RK11-C]] (below) is the earliest documented version, there are a few clues which indicate that there was an earlier version (one for which no documentation remains).

First, there is an image of a [[DEC indicator panel]] (image [http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/jpg/panels/RK11B.jpg here]) which seems to be from a pre-RK11-C; it clearly seems to be an RK11 panel of some sort, but the pinout of the RK11-C indicator panel connector (engineering drawing "RK11-C Indicator Connectors: RK11-C-23") has differences with this one.

In particular, on the panel in the image, the lower right line of lights on the panel shows 3 bits of Major State; on the RK11-C prints (on connector B32) there are 5 individual bits (Postamble, Checksum, Data, Header, Preamble). To explore this further, on the "Major States" RK11-C drawing (RK11-C-04), in the upper left corner, there is a row of 6 flops, each labeled with one of those states (plus one for 'Idle'), arranged in a chain - the output of each driving an individual light. However, the 3 bits for 'Major State' on the display panel imply it is binary coded - likely implemented with a counter.

Also, the signal "COUNT MSR" (likely 'Major State Register') is exactly what one would expect to see if the major state had previously been held in a counter, not a string of flops. It makes no sense to expend the effort synthesize that signal (on the next page, RK11-C-05, "MSR Control") when the individual signals which go into it could have been used, as is, to clock each flop in the chain.

A reasonable ''guess'', in light of these facts, is that in some previous version, a counter had been used, but had had a problem of some sort, and had therefore been replaced by the string of flops. (The reason is unknown, but perhaps it was a binary counter, not [[Gray code]], and the decoding into states was producing glitches.)

A plausible scenario is that such an earlier version was produced in very small numbers - perhaps as prototypes, only internal to DEC. (If there had been problems discovered with glitches in the major state counter, they would not have wanted to release it as a product.) Or if it was released as a product, perhaps they were all recalled and replaced with RK11-C's.

In this regard, it is interesting to note the DEC ''Spare Module Handbook'', lists only the RK11-C and -D, but '''does''' list the [[KT11-B]], a ''rara avis'' indeed. This argues that the predecessor did not exist 'in the wild'.

==RK11-C==

{{Main article | RK11-C disk controller}}

Like many of the earlier large peripheral controllers for the [[PDP-11]], the RK11-C was a large custom [[wire-wrap]]ped [[backplane]] which bolts into the front or back of a 19 inch rack, such as an [[H960 rack|H960]]; into it were plugged about 40 small M-Series [[FLIP CHIP]]s.

The RK11-C supports up to 4 drives per device bus (it uses 4 different 'select' lines on the bus, one of which is asserted at a time), and has two device busses.

==RK11-D==

The RK11-D was a re-implementation of the RK11-C on four [[DEC card form factor|quad]] cards (M7254-7), which plugged into a custom-wired 4 slot hex-high [[system unit]] [[backplane]], for a [[BA11 mounting boxes|BA11]] slide-out mounting box.

It was [[program compatible]] with the RK11-C, except that the RK11-D did not contain the Maintenance Register of the earlier controller. In the RK11-D, the bus location of the MR responds, but according to the engineering drawings, it reads as zero, and written data is ignored.

The RK11-D supports up to 8 drives per device bus (it uses 3 'select' lines on the bus, with the drive number encoded in binary), and has only one device bus.

The RK11-D also has a 6-word [[First-In First-Out buffer|FIFO buffer]] between the disk and the bus (see sheet 7 of the M7256 engineering drawings). The original RK11-C had only one word of buffering, which was probably not enough, and likely the reason for the [[RK11-C disk controller#Double Buffered RK11-C|double-buffered RK11-C version]].

==RK11-E==

The RK11-E (sometimes called the RK15) was a variant of the RK11-D which supported 18-bit data; it was used with the [[PDP-15]]. It used the same cards as the RK11-D, with a jumper selection for 18-bit operation, and a different clock crystal.

It was used with the [[UNICHANNEL 15 System|UC15 Unichannel]], which used a PDP-11 (usually a [[PDP-11/05]]) acting as a slave to the PDP-15; the RK11-E was plugged into the UNIBUS on the PDP-11.

It used the two [[UNIBUS parity]] lines for the two extra data bits on the 18-bit PDP-15. The two extra bits were not used by the PDP-11 or its memory, but went straight through the [[MX15-B Memory Multiplexer]], directly to the PDP-15's [[main memory]].

==RKV11-D==

[[Image:RKV11-D.jpg|200px|thumb|right|RKV11-D card cage and [[H780]] power supply]]

The RKV11-D is a variant of the RK11-D for the QBUS (the others are all UNIBUS).

It uses three of the four quad cards of the RK11-D (M7254-6), along with a replacement fourth card (M7268), in a different custom 4 slot quad-high system unit backplane. The M7268 is connected via two pairs of [[flat cable]]s to two dual cards, one of which (M7269) plugs into a QBUS backplane slot, and the other (M993-YA) into the first RK05 drive. The RKV11-D is mounted in a [[BA11-M]] style mounting box with [[H780]] power supply. The [[BA11-M]] front panel is replaced with an expansion box front panel, with a single indicator for '''DCOK'''.

It is program compatible with the RK11-D, except that it only supports [[Q16]] QBUS mode when writing data. The two extended memory bits in the CSR have no effect; they may be read and written, but are not connected to anything.

==Device registers==

{| border=1
! Register !! Abbreviation !! Address
|-
|Drive Status Register || RKDS || 777400
|-
|Error Register || RKER || 777402
|-
|Control Status Register || RKCS || 777404
|-
|Word Count Register || RKWC || 777406
|-
|Current Bus Address Register || RKBA || 777410
|-
|Disk Address Register || RKDA || 777412
|-
|Maintenance Register || RKMR || 777414
|-
|Data Buffer Register || RKDB || 777416
|}

===777400: Drive Status Register (RKDS)===

{{16bit-header}}
| colspan=3 | Drive ID || DPL || RK05 || DRU || SIN || SCOK || DRY || R/W/S Ready || WPS || SC=CA || colspan=4 | Sector Counter
{{16bitoctal-bitout}}

Note that in the '''''diagram''''' of this register in the 'peripherals handbook' (both 1975 and 1976 editions), bits 7 and 6 are labelled incorrectly; the ''table'' which lists the bits has them correctly.

(To confirm this, consult the RK11-D print set, M7254 page 3; the dual 4->1 muxes which fill this page are the source of the RKDS, RKER, etc registers.)

The name of bit 6 has changed slightly from the RK11-C to the -D ("Access Ready" to "R/W/S Ready"), but it seems to be basically the same functionality.

===777402: Error Register (RKER)===

{{16bit-header}}
| DRE || OVR || WLO || SKE || PGE || NXM || DLT || RTE || NXD || NXC || NXS || colspan=3 | || CSE || WCE
{{16bitoctal-bitout}}

===777404: Control Status Register (RKCS)===
{{16bit-header}}
| ERR || H.E. || SCP || M || IBA || FMT || R/WA || SSE || RDY || IDE || colspan=2 | EX. MEM || colspan=3 | FUNCTION || GO
{{16bitoctal-bitout}}

Bit 9 is"Read/Write All" in the RK11-C, and unused in the -D; bit 12 is "Maint" in the -C, and unused in the -D.

{| class="wikitable"
! Command !! Code || In CSR
|-
| Reset Controller || 0 || 0
|-
| Write || 1 || 02
|-
| Read || 2 || 04
|-
| Write Check || 3 || 06
|-
| Seek || 4 || 010
|-
| Read Check || 5 || 012
|-
| Reset Drive || 6 || 014
|-
| Write Lock || 7 || 016
|}

===777406: Word Count Register (RKWC)===
{{16bit-header}}
| colspan=16 | WC15 <---> WC00
{{16bitoctal-bitout}}

===777410: Current Bus Address Register (RKBA)===
{{16bit-header}}
| colspan=15 | BA15 <---> BA01 || Unused
{{16bitoctal-bitout}}

===777412: Disk Address Register (RKDA)===
{{16bit-header}}
| colspan=3 | DRIVE SELECT || colspan=8 | CYLINDER ADDRESS || SUR || colspan=4 | SECTOR ADDRESS
{{16bitoctal-bitout}}

===777414: Maintenance Register (RKMR)===
{{16bit-header}}
| M. RCP || M. RDP || M. SPS || M. ADA || M. LAI || colspan=3 | || M. DRY || M. R/W/S || colspan=2 | || colspan=4 | MAINT. SECTOR COUNTER
{{16bitoctal-bitout}}

This register is not present in the RK11-D; it reads as 0, and writes to it are discarded.

===777416: Data Buffer Register (RKDB)===
{{16bit-header}}
| colspan=16 | DB15 <---> DB00
{{16bitoctal-bitout}}

==PDP-11 bootstraps==

===Disk 0===

{| border=1
! Address !! Data !! Mnemonic !! Description
|- style="background-color: #ccccdd;"
|1000||012700||MOV #177406,R0 ||Move the address of the Word Count register into R0
|- style="background-color: #ccccff;"
|1002||177406|| || (constant)
|- style="background-color: #ccccdd;"
|1004||012710||MOV #177400,(R0) ||Move block size (negative) into Word Count register
|- style="background-color: #ccccff;"
|1006||177400|| || (constant)
|- style="background-color: #ccccdd;"
|1010||012740||MOV #5,-(R0) ||Move 'Read Go' command into CSR
|- style="background-color: #ccccff;"
|1012||000005|| || (constant)
|- style="background-color: #ccccdd;"
|1014||105710||TSTB (R0) ||Test for 'Done' bit in CSR
|- style="background-color: #ccccff;"
|1016||100376||BPL 1014 ||Jump backward if not set
|- style="background-color: #ccccdd;"
|1020||005007||CLR PC ||Start loaded bootstrap with jump to 0
|}

Note that the INIT pulse caused by hitting the 'Start' button will clear the Bus Adddress register, so the loaded block will be placed at location 0.

===Disk ''n''===

This bootstrap will boot from any disk in a daisy-chained multi-drive configuration. Memory location octal 1006 contains the unit number, as follows:
<table>
<tr>
<td>
{| border=1
! Address !! Data !! Mnemonic !! Description
|- style="background-color: #ccccdd;"
| 1000 || 012700 || MOV #177406, R0 || Store the address of the Word Count register in r0
|- style="background-color: #ccccff;"
| 1002 || 177406 || (constant) || (Which is 177406)
|- style="background-color: #ccccdd;"
| 1004 || 012760 || MOV xxxxxx, 000004(R0) || Store the disk ID number in the Disk Address register
|- style="background-color: #ccccff;"
| 1006 || xxxxxx || (disk ID number) || The disk number goes here.
|- style="background-color: #ccccdd;"
| 1010 || 000004 || (index) ||
|- style="background-color: #ccccff;"
| 1012 || 012700 || MOV #177406, R0 || Store the addresss of the Word Count register in r0
|- style="background-color: #ccccdd;"
| 1014 || 177406 || (constant) || (Which is 177406)
|- style="background-color: #ccccff;"
| 1016 || 012710 || MOV #177400, (R0) || Store 177400 into the Word Count register,
|- style="background-color: #ccccdd;"
| 1020 || 177400 || (constant) || meaning that octal 400 words are to be read.
|- style="background-color: #ccccff;"
| 1022 || 012740 || MOV #000005, -(R0) || Store 5 into the Control Status register
|- style="background-color: #ccccdd;"
| 1024 || 000005 || (constant) || selecting the function "read" with 4, and "go" with 1
|- style="background-color: #ccccff;"
| 1026 || 105710 || TSTB (R0) || Test the Control Status Register (upper) byte
|- style="background-color: #ccccdd;"
| 1030 || 100376 || BPL *-1 || Repeat if it's positive, that is Control Ready is cleared
|- style="background-color: #ccccff;"
| 1032 || 005007 || CLR PC || If not, clear the Program Counter (essentially, jump to 0)
|}
</td>
<td>
{| border=1
! Value !! Unit
|- style="background-color: #ccccdd;"
| 020000 || Unit 1
|- style="background-color: #ccccff;"
| 040000 || Unit 2
|- style="background-color: #ccccdd;"
| 060000 || Unit 3
|- style="background-color: #ccccff;"
| 100000 || Unit 4
|- style="background-color: #ccccdd;"
| 120000 || Unit 5
|- style="background-color: #ccccff;"
| 140000 || Unit 6
|- style="background-color: #ccccdd;"
| 160000 || Unit 7
|}
</td>
</tr>
</table>

==External links==

* [http://www.bitsavers.org/www.computer.museum.uq.edu.au/pdf/DEC-11-HRKDA-B-D%20RK11D%20and%20RK11-E%20Moving%20Head%20Disk%20Drive%20Controller%20Manual.pdf RK11-D and RK11-E moving head disk drive controller manual] (DEC-11-HRKDA-B-D)
* [http://www.bitsavers.org/www.computer.museum.uq.edu.au/pdf/EK-RK11D-OP-001%20RK11-D%20and%20RK11-E%20Moving%20Head%20Disk%20Drive%20Controller%20User's%20Manual.pdf RK11-D and RK11-E moving head disk drive controller user's manual] (EK-RK11D-OP-001)
* [http://www.bitsavers.org/pdf/dec/unibus/EK-RK11D-MM-002.pdf RK11-D and RK11-E moving head disk drive controller manual] (EK-RK11D-MM-002)
* [http://www.bitsavers.org/pdf/dec/qbus/EK-RKV11-OP-001_RKV11-D_Disk_Drive_Controller_Users_Manual_Jul1977.pdf RKV11-D disk drive controller user's manual] (EK-RKV11-0P-001)
* [http://www.bitsavers.org/pdf/dec/unibus/RK11-D_RevP_Engineering_Drawings_Oct75.pdf RK11-D disk drive controller engineering drawings] (Rev P, 10-1975)
* [http://www.bitsavers.org/pdf/dec/unibus/RK11-D_RevR_Engineering_Drawings_Oct76.pdf RK11-D Engineering Drawings] (Rev R, 10-1976)
* [http://www.bitsavers.org/pdf/dec/unibus/RK11-D_ECOs.pdf RK11-D ECOs]

==Further reading==

* ''RKV11-D disk drive controller technical manual'' (not available online, but in fiche - EP-RKV11-TM-001)
* ''RKV11-D Field Maintenance Print Set (MP00223)'' (not available online)

[[Category: UNIBUS Storage Controllers]]
[[Category: QBUS Storage Controllers]]
[[Category: DEC Documentation Errors]]

File:RKV11-D.jpg

2024-09-26T16:49:24Z

Glitch: RKV11-D backplane and power supply removed from mounting box

RKV11-D backplane and power supply removed from mounting box

H780 power supply

2024-09-26T16:47:16Z

Glitch: Adding H780 picture, mentioning use in RKV11-D

[[Image:H780.jpg|200px|thumb|right|H780 separated from chassis]]

The '''H780 power supply''' was the [[power supply]] for the [[BA11-M mounting box]], the first [[QBUS]] [[PDP-11]] [[mounting box]] from [[Digital Equipment Corporation|DEC]]. It provided 18A of +5V, and 3.5A of +12V). It was also used in the [[RKV11-D]] [[QBUS]] controller for RK moving-[[head]] [[magnetic storage|magnetic]] [[disk]] [[drive]]s ([[RK02/03 disk drive|RK02]]-[[RK05 disk drive|RK05]]).

==External links==

* [https://manx-docs.org/collections/antonio/dec/h780cop1.pdf H780-C, -D, -H, -J, -K, -L power supply user's manual] (EK-H780C-OP-001)
* [http://www.bitsavers.org/pdf/dec/qbus/Digital_Microcomputer_Interfaces_Handbook_1980.pdf microcomputer interfaces handbook] - the H780 is covered on pp. 385-419 (pp. 393-427 of the PDF)
* [http://www.bitsavers.org/pdf/dec/qbus/Digital_Microcomputer_Products_Handbook_1985.pdf Microcomputer Products Handbook] - the H780 is covered in Chapter 58 (pp. 549-553 of the PDF)
* [http://www.bitsavers.org/pdf/dec/pdp11/1103/EK-LSI11-TM-002.pdf LSI-11, PDP-11/03 user's manual] (EK-LSI11-TM-002) - the H780 is covered in Sections 4.9 (pp. 77-86 of the PDF)
* [http://www.bitsavers.org/pdf/dec/pdp11/1103/1103_Schematics.pdf PDP-11/03 Engineering Drawings] - the H780 is covered on pp. 155-169 of the PDF

[[Category: DEC Power Supplies]]

File:H780.jpg

2024-09-26T16:41:16Z

Glitch: DEC H780 power supply

DEC H780 power supply

Talk:QBUS backplanes

2024-07-28T14:48:56Z

Glitch: Height vs. Width in QBUS/DEC Backplanes Section

==Height vs. Width in DEC Backplanes Section==

Is it alright to change the table heading "Height" to "Width" in the '''DEC Backplanes''' section? "Height" in this context should refer to the module's size (dual, quad, hex).

User talk:Glitch

2024-07-27T19:52:42Z

Glitch: /* Show preview */

==Show preview==

Use of the 'Show preview' button will save you from having to fix some errors. (I cheerfully admit I don't use it as much as I should; I missed [https://gunkies.org/w/index.php?title=MMV11-A_QBUS_core_memory&curid=4842&diff=34906&oldid=34905 this one] because I only used 'Show changes'; 'Show preview' would have shown the error more visibly.) [[User:Jnc|Jnc]] ([[User talk:Jnc|talk]]) 21:45, 27 July 2024 (CEST)

Roger, kinda new to the process!

BA213 Enclosure

2024-07-27T19:12:48Z

Glitch:

[[Image:decserver_550_closed.jpeg|200px|thumb|right|[[DECserver 500|DECserver 550]] in a BA213 pedestal enclosure, front cover installed]]

[[Image:decserver_550_open.jpeg|200px|thumb|right|[[DECserver 500|DECserver 550]] in a BA213 pedestal enclosure, front cover removed]]

[[Image:ba213_key.jpeg|200px|thumb|right|Plastic key for locking/unlocking BA213 front covers]]

The '''BA213 Enclosure''' is a [[QBUS]] [[mounting box]] from [[Digital Equipment Corporation|DEC]] which is available in rack-mount, wall-mount, pedestal, single-[[cabinet]] (in an [[H9644]]), and double-cabinet versions. It is the 'bigger brother' to the [[BA23 Enclosure]], and the sibling to the [[BA123 Enclosure]].

It contains a single, 12-s1ot, [[DEC card form factor|quad]]-height [[backplane]], with all 12 slots are [[QBUS#Backplanes|Q/CD]] slots; that backplane cannot be expanded.

Pedestal mounted BA213 enclosures may include a front cover, which is removed by unlocking with a universal tubular plastic key. Once unlocked, the front cover lifts up and pulls forward.

The BA213 power supply uses an IEC C16 high-temperature 15A power inlet connector, which is not compatible with the more common IEC C13 power cables typically used with computers as the keying feature prevents insertion of C13 cable ends. An IEC C15 end is required, such cables are commonly used with carrier-grade network equipment and are readily available.

==Airflow==

The BA213 draws cooling air from the bottom, blows it through the [[QBus]] cards, and exhausts it through the top. Cooling fans may be variable speed.

==Wheels==

Pedestal mounted BA213 enclosures include wheels, which allow the enclosure to be rolled around. These wheels are not ''caster wheels'', they are fixed roller-type wheels, which makes turning difficult. This feature does increase appropriateness for [[VAX jousting]] applications.

==BA213 Usage==

The BA213 enclosure was used for a number of [[MicroVAX]] systems, as well as the [[DECserver 500]] series of [[terminal server]] devices. When used as the enclosure for a [[DECserver 500]], the top space does not include drive mounting hardware, and there is no translucent window in the front cover.

==External links==

* [http://bitsavers.trailing-edge.com/scandocs.trailing-edge.com/micropdp11-volume_2_enclosures-EK-189AA-MG-001.pdf BA213 Enclosure Maintenance] (EK-189AA-MG-001)
* [https://microvax2.org/wp/2017/05/24/ba213-power-supply-upgrade/ BA213 power supply replacement] from [https://microvax2.org MicroVAX II Museum]

[[Category: DEC Mounting Boxes]]
[[Category: QBUS Hardware]]

BA213 Enclosure

2024-07-27T19:11:46Z

Glitch: Adding note about C16 power inlet connector

[[Image:decserver_550_closed.jpeg|200px|thumb|right|[[DECserver 500|DECserver 550]] in a BA213 pedestal enclosure, front cover installed]]

[[Image:decserver_550_open.jpeg|200px|thumb|right|[[DECserver 500|DECserver 550]] in a BA213 pedestal enclosure, front cover removed]]

[[Image:ba213_key.jpeg|200px|thumb|right|Plastic key for locking/unlocking BA213 front covers]]

The '''BA213 Enclosure''' is a [[QBUS]] [[mounting box]] from [[Digital Equipment Corporation|DEC]] which is available in rack-mount, wall-mount, pedestal, single-[[cabinet]] (in an [[H9644]]), and double-cabinet versions. It is the 'bigger brother' to the [[BA23 Enclosure]], and the sibling to the [[BA123 Enclosure]].

It contains a single, 12-s1ot, [[DEC card form factor|quad]]-height [[backplane]], with all 12 slots are [[QBUS#Backplanes|Q/CD]] slots; that backplane cannot be expanded.

Pedestal mounted BA213 enclosures may include a front cover, which is removed by unlocking with a universal tubular plastic key. Once unlocked, the front cover lifts up and pulls forward.

The BA213 power supply uses an IEC C16 high-temperature 15A power inlet connector, which is not compatible with the more common IEC C13 power cables typically used with computers.

==Airflow==

The BA213 draws cooling air from the bottom, blows it through the [[QBus]] cards, and exhausts it through the top. Cooling fans may be variable speed.

==Wheels==

Pedestal mounted BA213 enclosures include wheels, which allow the enclosure to be rolled around. These wheels are not ''caster wheels'', they are fixed roller-type wheels, which makes turning difficult. This feature does increase appropriateness for [[VAX jousting]] applications.

==BA213 Usage==

The BA213 enclosure was used for a number of [[MicroVAX]] systems, as well as the [[DECserver 500]] series of [[terminal server]] devices. When used as the enclosure for a [[DECserver 500]], the top space does not include drive mounting hardware, and there is no translucent window in the front cover.

==External links==

* [http://bitsavers.trailing-edge.com/scandocs.trailing-edge.com/micropdp11-volume_2_enclosures-EK-189AA-MG-001.pdf BA213 Enclosure Maintenance] (EK-189AA-MG-001)
* [https://microvax2.org/wp/2017/05/24/ba213-power-supply-upgrade/ BA213 power supply replacement] from [https://microvax2.org MicroVAX II Museum]

[[Category: DEC Mounting Boxes]]
[[Category: QBUS Hardware]]

BA213 Enclosure

2024-07-27T19:02:53Z

Glitch: /* Airflow */

[[Image:decserver_550_closed.jpeg|200px|thumb|right|[[DECserver 500|DECserver 550]] in a BA213 pedestal enclosure, front cover installed]]

[[Image:decserver_550_open.jpeg|200px|thumb|right|[[DECserver 500|DECserver 550]] in a BA213 pedestal enclosure, front cover removed]]

[[Image:ba213_key.jpeg|200px|thumb|right|Plastic key for locking/unlocking BA213 front covers]]

The '''BA213 Enclosure''' is a [[QBUS]] [[mounting box]] from [[Digital Equipment Corporation|DEC]] which is available in rack-mount, wall-mount, pedestal, single-[[cabinet]] (in an [[H9644]]), and double-cabinet versions. It is the 'bigger brother' to the [[BA23 Enclosure]], and the sibling to the [[BA123 Enclosure]].

It contains a single, 12-s1ot, [[DEC card form factor|quad]]-height [[backplane]], with all 12 slots are [[QBUS#Backplanes|Q/CD]] slots; that backplane cannot be expanded.

Pedestal mounted BA213 enclosures may include a front cover, which is removed by unlocking with a universal tubular plastic key. Once unlocked, the front cover lifts up and pulls forward.

==Airflow==

The BA213 draws cooling air from the bottom, blows it through the [[QBus]] cards, and exhausts it through the top. Cooling fans may be variable speed.

==Wheels==

Pedestal mounted BA213 enclosures include wheels, which allow the enclosure to be rolled around. These wheels are not ''caster wheels'', they are fixed roller-type wheels, which makes turning difficult. This feature does increase appropriateness for [[VAX jousting]] applications.

==BA213 Usage==

The BA213 enclosure was used for a number of [[MicroVAX]] systems, as well as the [[DECserver 500]] series of [[terminal server]] devices. When used as the enclosure for a [[DECserver 500]], the top space does not include drive mounting hardware, and there is no translucent window in the front cover.

==External links==

* [http://bitsavers.trailing-edge.com/scandocs.trailing-edge.com/micropdp11-volume_2_enclosures-EK-189AA-MG-001.pdf BA213 Enclosure Maintenance] (EK-189AA-MG-001)
* [https://microvax2.org/wp/2017/05/24/ba213-power-supply-upgrade/ BA213 power supply replacement] from [https://microvax2.org MicroVAX II Museum]

[[Category: DEC Mounting Boxes]]
[[Category: QBUS Hardware]]

DECserver 500

2024-07-27T19:01:49Z

Glitch:

[[Image:decserver_550_closed.jpeg|200px|thumb|right|Pedestal-mounted DECserver 550 with front cover installed]]

[[Image:decserver_550_open.jpeg|200px|thumb|right|Pedestal-mounted DECserver 550 with front cover removed]]

[[Image:decserver_550_nameplate.jpeg|200px|thumb|right|DECserver 550 nameplate]]

The '''DECserver 500''' series is a line [[DEC]] [[terminal server]] devices. They are housed in a [[BA213]] [[S-Box]] [[QBus]] enclosure, and include:

* [[KDJ11-D]] J-11 processor
* [[DESQA]] Ethernet controller
* One or more [[CXY08 8-Line Asynchronous Multiplexer]] and/or [[CXA16]] 16-line serial multiplexer

The DECserver 500 series does not store configuration or firmware locally; rather, they are down-line loaded over [[Ethernet]] via [[MOP]].

DECserver 500

2024-07-27T19:01:35Z

Glitch:

[[Image:decserver_550_closed.jpeg|200px|thumb|right|Pedestal-mounted DECserver 550 with front cover installed]]

[[Image:decserver_550_open.jpeg|200px|thumb|right|Pedestal-mounted DECserver 550 with front cover removed]]

[[Image:decserver_550_nameplate.jpeg|200px|thumb|right|DECserver 550 nameplate]]

The '''DECserver 500''' series is a line [[DEC]] [[terminal server]] devices. They are housed in a [[BA213]] [[S-Box]] [[QBus]] enclosure, and include:

* [[KDJ11-D]] J-11 processor
* [[DESQA]] Ethernet controller
* One or more [[CXY08 8-Line Asynchronous Multiplexer]] or [[CXA16]] 16-line serial multiplexer

The DECserver 500 series does not store configuration or firmware locally; rather, they are down-line loaded over [[Ethernet]] via [[MOP]].

DECserver 500

2024-07-27T18:59:46Z

Glitch:

[[Image:decserver_550_closed.jpeg|200px|thumb|right|Pedestal-mounted DECserver 550 with front cover installed]]

[[Image:decserver_550_open.jpeg|200px|thumb|right|Pedestal-mounted DECserver 550 with front cover removed]]

[[Image:decserver_550_nameplate.jpeg|200px|thumb|right|DECserver 550 nameplate]]

The '''DECserver 500''' series is a line [[DEC]] [[terminal server]] devices. They are housed in a [[BA213]] [[S-Box]] [[QBus]] enclosure, and include:

* [[KDJ11-D]] J-11 processor
* [[DESQA]] Ethernet controller
* One or more [[CXY08]] 8-line or [[CXA16]] 16-line serial interfaces

The DECserver 500 series does not store configuration or firmware locally; rather, they are down-line loaded over [[Ethernet]] via [[MOP]].

BA213 Enclosure

2024-07-27T18:55:00Z

Glitch: Adding link to MVII Museum PSU replacement writeup

[[Image:decserver_550_closed.jpeg|200px|thumb|right|[[DECserver 500|DECserver 550]] in a BA213 pedestal enclosure, front cover installed]]

[[Image:decserver_550_open.jpeg|200px|thumb|right|[[DECserver 500|DECserver 550]] in a BA213 pedestal enclosure, front cover removed]]

[[Image:ba213_key.jpeg|200px|thumb|right|Plastic key for locking/unlocking BA213 front covers]]

The '''BA213 Enclosure''' is a [[QBUS]] [[mounting box]] from [[Digital Equipment Corporation|DEC]] which is available in rack-mount, wall-mount, pedestal, single-[[cabinet]] (in an [[H9644]]), and double-cabinet versions. It is the 'bigger brother' to the [[BA23 Enclosure]], and the sibling to the [[BA123 Enclosure]].

It contains a single, 12-s1ot, [[DEC card form factor|quad]]-height [[backplane]], with all 12 slots are [[QBUS#Backplanes|Q/CD]] slots; that backplane cannot be expanded.

Pedestal mounted BA213 enclosures may include a front cover, which is removed by unlocking with a universal tubular plastic key. Once unlocked, the front cover lifts up and pulls forward.

==Airflow==

The BA213 draws cooling air from the bottom, and exhausts it through the top. Cooling fans may be variable speed.

==Wheels==

Pedestal mounted BA213 enclosures include wheels, which allow the enclosure to be rolled around. These wheels are not ''caster wheels'', they are fixed roller-type wheels, which makes turning difficult. This feature does increase appropriateness for [[VAX jousting]] applications.

==BA213 Usage==

The BA213 enclosure was used for a number of [[MicroVAX]] systems, as well as the [[DECserver 500]] series of [[terminal server]] devices. When used as the enclosure for a [[DECserver 500]], the top space does not include drive mounting hardware, and there is no translucent window in the front cover.

==External links==

* [http://bitsavers.trailing-edge.com/scandocs.trailing-edge.com/micropdp11-volume_2_enclosures-EK-189AA-MG-001.pdf BA213 Enclosure Maintenance] (EK-189AA-MG-001)
* [https://microvax2.org/wp/2017/05/24/ba213-power-supply-upgrade/ BA213 power supply replacement] from [https://microvax2.org MicroVAX II Museum]

[[Category: DEC Mounting Boxes]]
[[Category: QBUS Hardware]]

BA213 Enclosure

2024-07-27T18:53:04Z

Glitch: /* BA213 Usage */

[[Image:decserver_550_closed.jpeg|200px|thumb|right|[[DECserver 500|DECserver 550]] in a BA213 pedestal enclosure, front cover installed]]

[[Image:decserver_550_open.jpeg|200px|thumb|right|[[DECserver 500|DECserver 550]] in a BA213 pedestal enclosure, front cover removed]]

[[Image:ba213_key.jpeg|200px|thumb|right|Plastic key for locking/unlocking BA213 front covers]]

The '''BA213 Enclosure''' is a [[QBUS]] [[mounting box]] from [[Digital Equipment Corporation|DEC]] which is available in rack-mount, wall-mount, pedestal, single-[[cabinet]] (in an [[H9644]]), and double-cabinet versions. It is the 'bigger brother' to the [[BA23 Enclosure]], and the sibling to the [[BA123 Enclosure]].

It contains a single, 12-s1ot, [[DEC card form factor|quad]]-height [[backplane]], with all 12 slots are [[QBUS#Backplanes|Q/CD]] slots; that backplane cannot be expanded.

Pedestal mounted BA213 enclosures may include a front cover, which is removed by unlocking with a universal tubular plastic key. Once unlocked, the front cover lifts up and pulls forward.

==Airflow==

The BA213 draws cooling air from the bottom, and exhausts it through the top. Cooling fans may be variable speed.

==Wheels==

Pedestal mounted BA213 enclosures include wheels, which allow the enclosure to be rolled around. These wheels are not ''caster wheels'', they are fixed roller-type wheels, which makes turning difficult. This feature does increase appropriateness for [[VAX jousting]] applications.

==BA213 Usage==

The BA213 enclosure was used for a number of [[MicroVAX]] systems, as well as the [[DECserver 500]] series of [[terminal server]] devices. When used as the enclosure for a [[DECserver 500]], the top space does not include drive mounting hardware, and there is no translucent window in the front cover.

==External links==

* [http://bitsavers.trailing-edge.com/scandocs.trailing-edge.com/micropdp11-volume_2_enclosures-EK-189AA-MG-001.pdf BA213 Enclosure Maintenance] (EK-189AA-MG-001)

[[Category: DEC Mounting Boxes]]
[[Category: QBUS Hardware]]

DECserver 500

2024-07-27T18:49:06Z

Glitch:

[[Image:decserver_550_closed.jpeg|200px|thumb|right|Pedestal-mounted DECserver 550 with front cover installed]]

[[Image:decserver_550_open.jpeg|200px|thumb|right|Pedestal-mounted DECserver 550 with front cover removed]]

[[Image:decserver_550_nameplate.jpeg|200px|thumb|right|DECserver 550 nameplate]]

The '''DECserver 500''' series is a line [[DEC]] [[terminal server]] devices. They are housed in a [[BA213]] [[S-Box]] [[QBus]] enclosure, and include:

* [[KDJ11-D]] J-11 processor
* [[DESQA]] Ethernet controller
* One or more [[CYX08]] 8-line or [[CXA16]] 16-line serial interfaces

The DECserver 500 series does not store configuration or firmware locally; rather, they are down-line loaded over [[Ethernet]] via [[MOP]].

BA213 Enclosure

2024-07-27T18:47:49Z

Glitch: Adding BA213 pictures, information

[[Image:decserver_550_closed.jpeg|200px|thumb|right|[[DECserver 500|DECserver 550]] in a BA213 pedestal enclosure, front cover installed]]

[[Image:decserver_550_open.jpeg|200px|thumb|right|[[DECserver 500|DECserver 550]] in a BA213 pedestal enclosure, front cover removed]]

[[Image:ba213_key.jpeg|200px|thumb|right|Plastic key for locking/unlocking BA213 front covers]]

The '''BA213 Enclosure''' is a [[QBUS]] [[mounting box]] from [[Digital Equipment Corporation|DEC]] which is available in rack-mount, wall-mount, pedestal, single-[[cabinet]] (in an [[H9644]]), and double-cabinet versions. It is the 'bigger brother' to the [[BA23 Enclosure]], and the sibling to the [[BA123 Enclosure]].

It contains a single, 12-s1ot, [[DEC card form factor|quad]]-height [[backplane]], with all 12 slots are [[QBUS#Backplanes|Q/CD]] slots; that backplane cannot be expanded.

Pedestal mounted BA213 enclosures may include a front cover, which is removed by unlocking with a universal tubular plastic key. Once unlocked, the front cover lifts up and pulls forward.

==Airflow==

The BA213 draws cooling air from the bottom, and exhausts it through the top. Cooling fans may be variable speed.

==Wheels==

Pedestal mounted BA213 enclosures include wheels, which allow the enclosure to be rolled around. These wheels are not ''caster wheels'', they are fixed roller-type wheels, which makes turning difficult. This feature does increase appropriateness for [[VAX jousting]] applications.

==BA213 Usage==

The BA213 enclosure was used for a number of [[MicroVAX]] systems, as well as the [[DECserver 500]] series of [[terminal server]] devices.

==External links==

* [http://bitsavers.trailing-edge.com/scandocs.trailing-edge.com/micropdp11-volume_2_enclosures-EK-189AA-MG-001.pdf BA213 Enclosure Maintenance] (EK-189AA-MG-001)

[[Category: DEC Mounting Boxes]]
[[Category: QBUS Hardware]]

File:Ba213 key.jpeg

2024-07-27T18:43:34Z

Glitch: Plastic key for BA213 front cover

Plastic key for BA213 front cover

DECserver 500

2024-07-27T18:32:38Z

Glitch:

[[Image:decserver_550_closed.jpeg|200px|thumb|right|DECserver 550 with front cover installed]]

[[Image:decserver_550_open.jpeg|200px|thumb|right|DECserver 550 with front cover removed]]

[[Image:decserver_550_nameplate.jpeg|200px|thumb|right|DECserver 550 nameplate]]

The '''DECserver 500''' series is a line [[DEC]] [[terminal server]] devices. They are housed in a [[BA213]] [[S-Box]] [[QBus]] enclosure, and include:

* [[KDJ11-D]] J-11 processor
* [[DESQA]] Ethernet controller
* One or more [[CYX08]] 8-line or [[CXA16]] 16-line serial interfaces

The DECserver 500 series does not store configuration or firmware locally; rather, they are down-line loaded over [[Ethernet]] via [[MOP]].

DECserver 500

2024-07-27T18:32:25Z

Glitch: Adding DECserver 550 pictures

[[Image:decserver_550_closed.jpeg|200px|thumb|right|DECserver 550 with front cover installed]]

[[Image:decserver_550_open.jpeg|200px|thumb|right|DECserver 550 with front cover removed]]

[[Image:decserver_550_nameplate.jpeg|200px|thumb|right|DECserver 550 nameplate]]

The '''DECserver 500''' series is a line [[DEC]] [[terminal server]] devices. They are housed in a [[BA213]] [[S-Box]] [[QBus]] enclosure, and include:

* [[KDJ11-D]] J-11 processor
* [[DESQA]]Ethernet controller
* One or more [[CYX08]] 8-line or [[CXA16]] 16-line serial interfaces

The DECserver 500 series does not store configuration or firmware locally; rather, they are down-line loaded over [[Ethernet]] via [[MOP]].

File:Decserver 550 nameplate.jpeg

2024-07-27T18:31:47Z

Glitch: DECserver 550 nameplate

DECserver 550 nameplate

File:Decserver 550 open.jpeg

2024-07-27T18:30:47Z

Glitch: DECserver 550 terminal server with front cover removed

DECserver 550 terminal server with front cover removed

File:Decserver 550 closed.jpeg

2024-07-27T18:28:59Z

Glitch: DECserver 550 terminal server with front cover installed

DECserver 550 terminal server with front cover installed

DECserver 500

2024-07-27T18:25:15Z

Glitch: Creating DECserver 500 page

The '''DECserver 500''' series is a line [[DEC]] [[terminal server]] devices. They are housed in a [[BA213]] [[S-Box]] [[QBus]] enclosure, and include:

* [[KDJ11-D]] J-11 processor
* [[DESQA]]Ethernet controller
* One or more [[CYX08]] 8-line or [[CXA16]] 16-line serial interfaces

The DECserver 500 series does not store configuration or firmware locally; rather, they are down-line loaded over [[Ethernet]] via [[MOP]].

KDJ11-D CPU

2024-07-27T14:09:02Z

Glitch: /* ROM Versions */

[[Image:KDJ11-D.jpg|200px|thumb|right|KDJ11-D; later variant, 1.5MB version]]

The '''KDJ11-D''' CPU board, formally named the '''KDJ11-D/S''' in the later variant (below), is the third [[QBUS]] [[Central Processing Unit|CPU]] card using the [[J-11 chip set]] of the [[PDP-11]] of the [[KDJ11 CPUs]]. It is a [[DEC card form factor|quad-height]] board, the '''M7554'''; it is available in the so-called [[S-box]] format, for the [[BA200]] enclosure. It was used in the [[PDP-11/53]] and the [[DECserver 500]] Series [[Terminal Server]].

Its principal difference from the KDJ11-B is that the KDJ11-D does not support the [[Private Memory Interconnect]] [[bus]] (a high-performance variant of the QBUS); instead, it provides either .5MB or 1.5 MB (depending on the exact model) of on-board [[main memory]] (with byte [[parity]]). (Additional memory, up to the 4MB limit of the J-11, can be utilized over the QBUS.)

It also does not support the [[FPJ11 floating point accelerator]] [[integrated circuit|chip]] (used to speed up the [[FP11 floating point|FP11]] implementation in the J-11), and it does not have a [[cache]]. It also only supports level 4 [[interrupt]]s on the QBUS (although requests at other levels are honoured; just treated as if they were level 4).

Similarly to the KDJ11-B, it also provides a built-in [[asynchronous serial line|serial]] line for console, and [[Read-only memory|ROM]]s to contain diagnostic and [[bootstrap]] programs. The KDJ11-D provides a second SLU, referred to as SLU 1 or DL1 in the documentation, at base address 17776500Q, vector 300Q. The Module User's Guide suggests that this SLU can be used for a printer, but the base address and vector make SLU 1 usable with default [[TU58]] configurations, whether a real drive or emulated.

==Board Versions==

The KDJ11-D comes in two quite different main variants; unfortunately, they use the same board number, so a visual inspection is needed to know which variant a particular KDJ11-D board is.

Versions of the early variant all utilize a large number of discrete [[logic]] chips, and hold 512KB of memory. The later, 're-engineered' (as the documentation calls it) variant, has moved most of the logic into two [[gate array]]s (DC7063 for control, and DC7064 for [[data path]]s), which made room for up to 1.5MB of memory.

The two versions are fairly distinct, visually: in the early variant, with the card oriented with the contact fingers at the bottom, the large DCJ11 CPU chip is placed horizontally in the centre of the card; in the re-engineered variant (shown above), it is placed vertically, on the right-hand edge of the card. (The two large chips next to it are the two gate arrays.)

The following versions of the 'early' variant exist:

* KDJ11-DA; 0.5MB, 15 MHz
* KDJ11-SA; BA200 box, 0.5MB, 15 MHz
* KDJ11-SB; BA200 box, 0.5MB, 18 MHz

The following are the versions of the 're-engineered' variant:

* KDJ11-DA (!); 0.5MB, 15 MHz
* KDJ11-DB; 1.5MB, 15 MHz
* KDJ11-SC; BA200 box, 1.5MB, 15 MHz
* KDJ11-SD; BA200 box, 1.5MB, 18 MHz

There .5MB/1.5MB versions are easy to tell apart visually: the .5MB cards have only two horizontal rows of [[DRAM]] chips in the large array on the left-hand side; on the 1.5MB cards, all six rows are present.

==ROM Versions==

The KDJ11-D supports the following ROMs:

{| class="wikitable"
| DEC Part Number || Version || Socket || Size || Application || Notes
|-
| 23-204E5-00 || 1.0 || E26 (High) || 16KB || [[PDP-11/53]] || Supports only English and Spanish language options
|-
| 23-205E5-00 || 1.0 || E34 (Low) || 16KB || [[PDP-11/53]] || Supports only English and Spanish language options
|-
| 23-261E5-00 || 2.0 || E26 (High) || 16KB || [[PDP-11/53]] || Multi-language support, latest version
|-
| 23-262E5-00 || 2.0 || E34 (Low) || 16KB || [[PDP-11/53]] || Multi-language support, latest version
|}

==External links==

* [http://www.bitsavers.org/pdf/dec/pdp11/1173/EK-KDJ1D-UG_KDJ11-D_May87.pdf KDJ11-D/S CPU Module User's Guide] (EK-KDJ1B-UG-002)
* [http://bitsavers.trailing-edge.com/scandocs.trailing-edge.com/micropdp11-volume1_system_cpus-EK-246AA-MG-001.pdf KDJ11-D/S CPU System Maintenance] (EK-246AA-MG-001)

[[Category: PDP-11 QBUS Processors]]

KDJ11-D CPU

2024-07-27T14:02:26Z

Glitch:

[[Image:KDJ11-D.jpg|200px|thumb|right|KDJ11-D; later variant, 1.5MB version]]

The '''KDJ11-D''' CPU board, formally named the '''KDJ11-D/S''' in the later variant (below), is the third [[QBUS]] [[Central Processing Unit|CPU]] card using the [[J-11 chip set]] of the [[PDP-11]] of the [[KDJ11 CPUs]]. It is a [[DEC card form factor|quad-height]] board, the '''M7554'''; it is available in the so-called [[S-box]] format, for the [[BA200]] enclosure. It was used in the [[PDP-11/53]] and the [[DECserver 500]] Series [[Terminal Server]].

Its principal difference from the KDJ11-B is that the KDJ11-D does not support the [[Private Memory Interconnect]] [[bus]] (a high-performance variant of the QBUS); instead, it provides either .5MB or 1.5 MB (depending on the exact model) of on-board [[main memory]] (with byte [[parity]]). (Additional memory, up to the 4MB limit of the J-11, can be utilized over the QBUS.)

It also does not support the [[FPJ11 floating point accelerator]] [[integrated circuit|chip]] (used to speed up the [[FP11 floating point|FP11]] implementation in the J-11), and it does not have a [[cache]]. It also only supports level 4 [[interrupt]]s on the QBUS (although requests at other levels are honoured; just treated as if they were level 4).

Similarly to the KDJ11-B, it also provides a built-in [[asynchronous serial line|serial]] line for console, and [[Read-only memory|ROM]]s to contain diagnostic and [[bootstrap]] programs. The KDJ11-D provides a second SLU, referred to as SLU 1 or DL1 in the documentation, at base address 17776500Q, vector 300Q. The Module User's Guide suggests that this SLU can be used for a printer, but the base address and vector make SLU 1 usable with default [[TU58]] configurations, whether a real drive or emulated.

==Board Versions==

The KDJ11-D comes in two quite different main variants; unfortunately, they use the same board number, so a visual inspection is needed to know which variant a particular KDJ11-D board is.

Versions of the early variant all utilize a large number of discrete [[logic]] chips, and hold 512KB of memory. The later, 're-engineered' (as the documentation calls it) variant, has moved most of the logic into two [[gate array]]s (DC7063 for control, and DC7064 for [[data path]]s), which made room for up to 1.5MB of memory.

The two versions are fairly distinct, visually: in the early variant, with the card oriented with the contact fingers at the bottom, the large DCJ11 CPU chip is placed horizontally in the centre of the card; in the re-engineered variant (shown above), it is placed vertically, on the right-hand edge of the card. (The two large chips next to it are the two gate arrays.)

The following versions of the 'early' variant exist:

* KDJ11-DA; 0.5MB, 15 MHz
* KDJ11-SA; BA200 box, 0.5MB, 15 MHz
* KDJ11-SB; BA200 box, 0.5MB, 18 MHz

The following are the versions of the 're-engineered' variant:

* KDJ11-DA (!); 0.5MB, 15 MHz
* KDJ11-DB; 1.5MB, 15 MHz
* KDJ11-SC; BA200 box, 1.5MB, 15 MHz
* KDJ11-SD; BA200 box, 1.5MB, 18 MHz

There .5MB/1.5MB versions are easy to tell apart visually: the .5MB cards have only two horizontal rows of [[DRAM]] chips in the large array on the left-hand side; on the 1.5MB cards, all six rows are present.

==ROM Versions==

The KDJ11-D supports the following ROMs:

{| class="wikitable"
| DEC Part Number || Version || Socket || Size || Application || Notes
|-
| 23-204E5-00 || 1.0 || E26 (High) || 16KB || [[PDP-11/53]] || Supports only English and Spanish
|-
| 23-205E5-00 || 1.0 || E34 (Low) || 16KB || [[PDP-11/53]] || Supports only English and Spanish
|-
| 23-261E5-00 || 2.0 || E26 (High) || 16KB || [[PDP-11/53]] || Multi-language support, latest version
|-
| 23-262E5-00 || 2.0 || E34 (Low) || 16KB || [[PDP-11/53]] || Multi-language support, latest version
|}

==External links==

* [http://www.bitsavers.org/pdf/dec/pdp11/1173/EK-KDJ1D-UG_KDJ11-D_May87.pdf KDJ11-D/S CPU Module User's Guide] (EK-KDJ1B-UG-002)
* [http://bitsavers.trailing-edge.com/scandocs.trailing-edge.com/micropdp11-volume1_system_cpus-EK-246AA-MG-001.pdf KDJ11-D/S CPU System Maintenance] (EK-246AA-MG-001)

[[Category: PDP-11 QBUS Processors]]

KDJ11-D CPU

2024-07-27T14:02:05Z

Glitch: Adding KDJ11-D ROM information

[[Image:KDJ11-D.jpg|200px|thumb|right|KDJ11-D; later variant, 1.5MB version]]

The '''KDJ11-D''' CPU board, formally named the '''KDJ11-D/S''' in the later variant (below), is the third [[QBUS]] [[Central Processing Unit|CPU]] card using the [[J-11 chip set]] of the [[PDP-11]] of the [[KDJ11 CPUs]]. It is a [[DEC card form factor|quad-height]] board, the '''M7554'''; it is available in the so-called [[S-box]] format, for the [[BA200]] enclosure. It was used in the [[PDP-11/53]] and the [[DECserver 500]] Series [[Terminal Server]].

Its principal difference from the KDJ11-B is that the KDJ11-D does not support the [[Private Memory Interconnect]] [[bus]] (a high-performance variant of the QBUS); instead, it provides either .5MB or 1.5 MB (depending on the exact model) of on-board [[main memory]] (with byte [[parity]]). (Additional memory, up to the 4MB limit of the J-11, can be utilized over the QBUS.)

It also does not support the [[FPJ11 floating point accelerator]] [[integrated circuit|chip]] (used to speed up the [[FP11 floating point|FP11]] implementation in the J-11), and it does not have a [[cache]]. It also only supports level 4 [[interrupt]]s on the QBUS (although requests at other levels are honoured; just treated as if they were level 4).

Similarly to the KDJ11-B, it also provides a built-in [[asynchronous serial line|serial]] line for console, and [[Read-only memory|ROM]]s to contain diagnostic and [[bootstrap]] programs. The KDJ11-D provides a second SLU, referred to as SLU 1 or DL1 in the documentation, at base address 17776500Q, vector 300Q. The Module User's Guide suggests that this SLU can be used for a printer, but the base address and vector make SLU 1 usable with default [[TU58]] configurations, whether a real drive or emulated.

==Versions==

The KDJ11-D comes in two quite different main variants; unfortunately, they use the same board number, so a visual inspection is needed to know which variant a particular KDJ11-D board is.

Versions of the early variant all utilize a large number of discrete [[logic]] chips, and hold 512KB of memory. The later, 're-engineered' (as the documentation calls it) variant, has moved most of the logic into two [[gate array]]s (DC7063 for control, and DC7064 for [[data path]]s), which made room for up to 1.5MB of memory.

The two versions are fairly distinct, visually: in the early variant, with the card oriented with the contact fingers at the bottom, the large DCJ11 CPU chip is placed horizontally in the centre of the card; in the re-engineered variant (shown above), it is placed vertically, on the right-hand edge of the card. (The two large chips next to it are the two gate arrays.)

The following versions of the 'early' variant exist:

* KDJ11-DA; 0.5MB, 15 MHz
* KDJ11-SA; BA200 box, 0.5MB, 15 MHz
* KDJ11-SB; BA200 box, 0.5MB, 18 MHz

The following are the versions of the 're-engineered' variant:

* KDJ11-DA (!); 0.5MB, 15 MHz
* KDJ11-DB; 1.5MB, 15 MHz
* KDJ11-SC; BA200 box, 1.5MB, 15 MHz
* KDJ11-SD; BA200 box, 1.5MB, 18 MHz

There .5MB/1.5MB versions are easy to tell apart visually: the .5MB cards have only two horizontal rows of [[DRAM]] chips in the large array on the left-hand side; on the 1.5MB cards, all six rows are present.

==ROM Versions==

The KDJ11-D supports the following ROMs:

{| class="wikitable"
| DEC Part Number || Version || Socket || Size || Application || Notes
|-
| 23-204E5-00 || 1.0 || E26 (High) || 16KB || [[PDP-11/53]] || Supports only English and Spanish
|-
| 23-205E5-00 || 1.0 || E34 (Low) || 16KB || [[PDP-11/53]] || Supports only English and Spanish
|-
| 23-261E5-00 || 2.0 || E26 (High) || 16KB || [[PDP-11/53]] || Multi-language support, latest version
|-
| 23-262E5-00 || 2.0 || E34 (Low) || 16KB || [[PDP-11/53]] || Multi-language support, latest version
|}

==External links==

* [http://www.bitsavers.org/pdf/dec/pdp11/1173/EK-KDJ1D-UG_KDJ11-D_May87.pdf KDJ11-D/S CPU Module User's Guide] (EK-KDJ1B-UG-002)
* [http://bitsavers.trailing-edge.com/scandocs.trailing-edge.com/micropdp11-volume1_system_cpus-EK-246AA-MG-001.pdf KDJ11-D/S CPU System Maintenance] (EK-246AA-MG-001)

[[Category: PDP-11 QBUS Processors]]

KDJ11-D CPU

2024-07-26T23:16:12Z

Glitch:

[[Image:KDJ11-D.jpg|200px|thumb|right|KDJ11-D; later variant, 1.5MB version]]

The '''KDJ11-D''' CPU board, formally named the '''KDJ11-D/S''' in the later variant (below), is the third [[QBUS]] [[Central Processing Unit|CPU]] card using the [[J-11 chip set]] of the [[PDP-11]] of the [[KDJ11 CPUs]]. It is a [[DEC card form factor|quad-height]] board, the '''M7554'''; it is available in the so-called [[S-box]] format, for the [[BA200]] enclosure. It was used in the [[PDP-11/53]] and the [[DECserver 500]] Series [[Terminal Server]].

Its principal difference from the KDJ11-B is that the KDJ11-D does not support the [[Private Memory Interconnect]] [[bus]] (a high-performance variant of the QBUS); instead, it provides either .5MB or 1.5 MB (depending on the exact model) of on-board [[main memory]] (with byte [[parity]]). (Additional memory, up to the 4MB limit of the J-11, can be utilized over the QBUS.)

It also does not support the [[FPJ11 floating point accelerator]] [[integrated circuit|chip]] (used to speed up the [[FP11 floating point|FP11]] implementation in the J-11), and it does not have a [[cache]]. It also only supports level 4 [[interrupt]]s on the QBUS (although requests at other levels are honoured; just treated as if they were level 4).

Similarly to the KDJ11-B, it also provides a built-in [[asynchronous serial line|serial]] line for console, and [[Read-only memory|ROM]]s to contain diagnostic and [[bootstrap]] programs. The KDJ11-D provides a second SLU, referred to as SLU 1 or DL1 in the documentation, at base address 17776500Q, vector 300Q. The Module User's Guide suggests that this SLU can be used for a printer, but the base address and vector make SLU 1 usable with default [[TU58]] configurations, whether a real drive or emulated.

==Versions==

The KDJ11-D comes in two quite different main variants; unfortunately, they use the same board number, so a visual inspection is needed to know which variant a particular KDJ11-D board is.

Versions of the early variant all utilize a large number of discrete [[logic]] chips, and hold 512KB of memory. The later, 're-engineered' (as the documentation calls it) variant, has moved most of the logic into two [[gate array]]s (DC7063 for control, and DC7064 for [[data path]]s), which made room for up to 1.5MB of memory.

The two versions are fairly distinct, visually: in the early variant, with the card oriented with the contact fingers at the bottom, the large DCJ11 CPU chip is placed horizontally in the centre of the card; in the re-engineered variant (shown above), it is placed vertically, on the right-hand edge of the card. (The two large chips next to it are the two gate arrays.)

The following versions of the 'early' variant exist:

* KDJ11-DA; 0.5MB, 15 MHz
* KDJ11-SA; BA200 box, 0.5MB, 15 MHz
* KDJ11-SB; BA200 box, 0.5MB, 18 MHz

The following are the versions of the 're-engineered' variant:

* KDJ11-DA (!); 0.5MB, 15 MHz
* KDJ11-DB; 1.5MB, 15 MHz
* KDJ11-SC; BA200 box, 1.5MB, 15 MHz
* KDJ11-SD; BA200 box, 1.5MB, 18 MHz

There .5MB/1.5MB versions are easy to tell apart visually: the .5MB cards have only two horizontal rows of [[DRAM]] chips in the large array on the left-hand side; on the 1.5MB cards, all six rows are present.

==External links==

* [http://www.bitsavers.org/pdf/dec/pdp11/1173/EK-KDJ1D-UG_KDJ11-D_May87.pdf KDJ11-D/S CPU Module User's Guide] (EK-KDJ1B-UG-002)
* [http://bitsavers.trailing-edge.com/scandocs.trailing-edge.com/micropdp11-volume1_system_cpus-EK-246AA-MG-001.pdf KDJ11-D/S CPU System Maintenance] (EK-246AA-MG-001)

[[Category: PDP-11 QBUS Processors]]

KDJ11-D CPU

2024-07-26T23:13:55Z

Glitch: Updating to reflect that the KDJ11-B has a single SLU, and that SLU 1 can be used for TU58

[[Image:KDJ11-D.jpg|200px|thumb|right|KDJ11-D; later variant, 1.5MB version]]

The '''KDJ11-D''' CPU board, formally named the '''KDJ11-D/S''' in the later variant (below), is the third [[QBUS]] [[Central Processing Unit|CPU]] card using the [[J-11 chip set]] of the [[PDP-11]] of the [[KDJ11 CPUs]]. It is a [[DEC card form factor|quad-height]] board, the '''M7554'''; it is available in the so-called [[S-box]] format, for the [[BA200]] enclosure. It was used in the [[PDP-11/53]] and the [[DECserver 500]] [[Terminal Server]].

Its principal difference from the KDJ11-B is that the KDJ11-D does not support the [[Private Memory Interconnect]] [[bus]] (a high-performance variant of the QBUS); instead, it provides either .5MB or 1.5 MB (depending on the exact model) of on-board [[main memory]] (with byte [[parity]]). (Additional memory, up to the 4MB limit of the J-11, can be utilized over the QBUS.)

It also does not support the [[FPJ11 floating point accelerator]] [[integrated circuit|chip]] (used to speed up the [[FP11 floating point|FP11]] implementation in the J-11), and it does not have a [[cache]]. It also only supports level 4 [[interrupt]]s on the QBUS (although requests at other levels are honoured; just treated as if they were level 4).

Similarly to the KDJ11-B, it also provides a built-in [[asynchronous serial line|serial]] line for console, and [[Read-only memory|ROM]]s to contain diagnostic and [[bootstrap]] programs. The KDJ11-D provides a second SLU, referred to as SLU 1 or DL1 in the documentation, at base address 17776500Q, vector 300Q. The Module User's Guide suggests that this SLU can be used for a printer, but the base address and vector make SLU 1 usable with default [[TU58]] configurations, whether a real drive or emulated.

==Versions==

The KDJ11-D comes in two quite different main variants; unfortunately, they use the same board number, so a visual inspection is needed to know which variant a particular KDJ11-D board is.

Versions of the early variant all utilize a large number of discrete [[logic]] chips, and hold 512KB of memory. The later, 're-engineered' (as the documentation calls it) variant, has moved most of the logic into two [[gate array]]s (DC7063 for control, and DC7064 for [[data path]]s), which made room for up to 1.5MB of memory.

The two versions are fairly distinct, visually: in the early variant, with the card oriented with the contact fingers at the bottom, the large DCJ11 CPU chip is placed horizontally in the centre of the card; in the re-engineered variant (shown above), it is placed vertically, on the right-hand edge of the card. (The two large chips next to it are the two gate arrays.)

The following versions of the 'early' variant exist:

* KDJ11-DA; 0.5MB, 15 MHz
* KDJ11-SA; BA200 box, 0.5MB, 15 MHz
* KDJ11-SB; BA200 box, 0.5MB, 18 MHz

The following are the versions of the 're-engineered' variant:

* KDJ11-DA (!); 0.5MB, 15 MHz
* KDJ11-DB; 1.5MB, 15 MHz
* KDJ11-SC; BA200 box, 1.5MB, 15 MHz
* KDJ11-SD; BA200 box, 1.5MB, 18 MHz

There .5MB/1.5MB versions are easy to tell apart visually: the .5MB cards have only two horizontal rows of [[DRAM]] chips in the large array on the left-hand side; on the 1.5MB cards, all six rows are present.

==External links==

* [http://www.bitsavers.org/pdf/dec/pdp11/1173/EK-KDJ1D-UG_KDJ11-D_May87.pdf KDJ11-D/S CPU Module User's Guide] (EK-KDJ1B-UG-002)
* [http://bitsavers.trailing-edge.com/scandocs.trailing-edge.com/micropdp11-volume1_system_cpus-EK-246AA-MG-001.pdf KDJ11-D/S CPU System Maintenance] (EK-246AA-MG-001)

[[Category: PDP-11 QBUS Processors]]

KDJ11-B CPU

2024-07-26T20:52:58Z

Glitch: Adding cache problems section, DC350 incompatibility section

[[Image:m8190.jpg|200px|thumb|right|M8190]]

The '''KDJ11-B''' CPU board (M8190) is the second-generation [[QBUS]] [[Central Processing Unit|CPU]] card using the [[J-11 chip set]] of the [[PDP-11]] (the first being the the [[KDJ11-A CPU]]). It is a [[DEC card form factor|quad-height]] board, and is used in the [[PDP-11/83]] and [[PDP-11/84]] systems.

Its principal improvement over the KDJ11-A is its support of the [[Private Memory Interconnect]] [[bus]], a high-performance variant of the QBUS; it also supports the [[KTJ11-B UNIBUS adapter]], a QBUS->[[UNIBUS]] adapter used in the PDP-11/84.

It also provides a built-in [[asynchronous serial line|serial]] console, [[Read-only memory|ROM]]s to contain diagnostic and [[bootstrap]] programs, and an [[EEPROM]] to contain configuration information.

Like the KDJ11-A, the -B also contains an 8K-byte write-through [[cache]] (set size 1, block size 1 16-bit [[word]]), protected by [[parity]]. The KDJ11-B additionally provides two sets of tag fields for each cache entry, so that the CPU and [[Direct Memory Access|DMA]] from the QBUS can interact with the cache simultaneously. Cache control logic inspects DMA transfers and invalidates cache entries for memory words which are written to by a device.

Also like the KDJ11-A, it can also use the [[FPJ11 floating point accelerator]] [[integrated circuit|chip]] to speed up the [[FP11 floating point|FP11]] implementation in the J-11.

As far as is known, the various models of the KDJ11-B differ only in their speed (CPU and [[clock]] [[crystal]]) and whether or not they come with the FPJ11. [[Digital Equipment Corporation|DEC]] documentation refers to certain models being used in certain machines, but as far as is known, in fact any model will work in any machine.

==Cache Problems==

The KDJ11-B cache implementation makes hard-to-diagnose stability problems a possibility. Below are some problems observed in a [https://forum.vcfed.org/index.php?threads/july-2024-ebay-qbus-lot-repair-thread.1249049/ VCFed Forums repair thread from July 2024]:

===Intermittent CPU Stoppage===

During testing of [[Clearpoint QED1]] and [[MSV11-J]] [[PMI]] memories, the system would randomly stop while running '''VMJAB0''', the [[MSV11-J]] exerciser from [[XXDP]]. There was no error printout, no trap messages, no HALT to [[ODT]], and the '''RUN''' lamp was out. The system came up from a restart and reported no errors in its self-tests. '''OKDAG0''', the KDJ11-B cluster diagnostics, reported no errors, even with the switches set to 000300Q for extended cache tag and data RAM tests. After entering field service mode in '''VMJAB0''' and disabling the J-11 cache, '''VMJAB0''' would run without error or stoppage. After an extended run of '''VMJAB0''', the system power-on diagnostics stopped with an error #162, which did not state that it was cache related, but should be -- #62 is a cache error, and for errors greater than 100, one subtracts 100 and uses the resulting number.

This problem was found to be a failing cache SRAM at position E10. The faulty chip was located through process of elimination, and was the fourth chip replaced. All other cache RAMs were OK.

===Consistent Error 62 with Printout===

During burn-in testing of a repaired KDJ11-B from a large lot of scrap [[QBus]] boards, the KDJ11-B began stopping on every reset with a #62 cache error. The error could be bypassed with a '''CTRL+O 4''' bypass. Once bypassed, the system could boot into [[XXDP]], but '''OKDAG0''' KDJ11-B cluster diagnostics reported no problems, even when run with the switches set to 000300Q for extended cache tag and data RAM tests.

This problem was found to be a failing cache SRAM at position E104, which is in the DMA tag RAM array. The faulty chip was located through process of elimination, and was the eleventh chip replaced. All other cache RAMs were OK.

===Consistent Error 62 with Lockup===

During burn-in testing of a repaired KDJ11-B from a large lot of scrap [[QBus]] boards, the KDJ11-B began locking up on every reset with test #62 displayed on the lights. The system locked up hard and could not be HALTed to [[ODT]] without a reboot. No error was printed to the console. The [[EEPROM]] was moved to another KDJ11-B and configured to enter [[ODT]] on power-on, and skip all testing. This allowed booting into [[XXDP]] and running '''OKDAG0''', KDJ11-B cluster diagnostics. With switches set to 000300Q for extended cache tag and data RAM tests, '''OKDAG0''' would stop with the message:

'''ERROR IN RECORDING HITS THROUGH HITS/MISS REGISTER'''

Error printout indicated that the hit/miss shift register was not recording any hits, and remaining 000000Q regardless of the hit pattern attempting to be written to it.

The hit/miss register is implemented in the J-11 processor itself, but is fed signals from the DC350 gate array, which contains the cache control registers. These signals are combined through a 74S260 dual 5-input NOR gate at E22. The 74S260 had failed, and resolved the error upon replacement.

==DC350 Gate Array Incompatibilities==

During the diagnosis of a cache problem in this [https://forum.vcfed.org/index.php?threads/july-2024-ebay-qbus-lot-repair-thread.1249049/ VCFed Forums repair thread from July 2024], it was discovered that DC350 gate arrays may not be interchangeable between board revisions. A LSI gold lid gate array from an early KDJ11-B with green top-side ECO was replaced with a silver lid gate array made in Japan from a later revision KDJ11-B. This resulted in a "mostly working" KDJ11-B, but '''OKDAG0''' cluster diagnostics would randomly stop to [[ODT]] or loop endlessly without printout of pass completion or errors, and never prompted for user input for the KDJ11-B lamp register test. It is assumed that the DC350 revision was incompatible with the board revision.

==See also==

* [[KDJ11-D CPU]]

==External links==

* [http://www.bitsavers.org/pdf/dec/pdp11/1173/EK-KDJ1B-UG_KDJ11-B_Nov86.pdf KDJ11-B CPU Module User's Guide] (EK-KDJ1B-UG-001)
* [http://www.bitsavers.org/pdf/dec/pdp11/1173/EK-247AA-MG-001_KDJ11-B_CPU_System_Maintenance_Nov88.pdf KDJ11-B CPU System Maintenance] (EK-247AA-MG-001)
* [http://www.bitsavers.org/pdf/dec/pdp11/1173/KDJ11-B_Processor_Spec_Jun1984.pdf KDJ11-B Processor Specification]
* [http://www.bitsavers.org/pdf/dec/pdp11/1184/MP-02015-01_11-84_Maintenance_Print_Set_198412.pdf 11/84 Field Maintenance Print Set (MP-02015-001)] - Contains KDJ11-B Field Maintenance Print Set (MP-01969-01) on pp. 94-126

[[Category: PDP-11 QBUS Processors]]
[[Category: Private Memory Interconnect]]

MLSI-BPA84

2024-07-24T18:50:47Z

Glitch: Adding MDB MLSI-BPA84 backplane assembly article

The [[MDB Systems]] MLSI-BPA84 is a third party [[QBus]] backplane/card guide assembly. It includes the [[40328]] QBus backplane in an 8-slot Q/Q configuration, and is wired via PCB for Q18. The backplane includes wire wrap pins and can be wrapped to Q22.

==External links==

* [https://archive.org/details/MDB_Chassis_Assemblies_for_use_with_LSI-11-2_and_11-23_Computers MDB Systems Chassis Assemblies ad]

MLSI-BA11-200

2024-07-24T18:46:09Z

Glitch: Adding initial article on MDB MLSI-BA11-200 chassis

The [[MDB Systems]] MLSI-BA11-200 is a third party [[QBus]] chassis, backplane, and power supply offering that is fully compatible with [[DEC]] [[QBus]] dual-height cards, and some quad-height cards. It includes an eight-slot quad height Q/Q backplane. Original backplanes appear to be Q18 only, but can be wire wrapped to Q22.

A small [[PDP-11/03]] style front panel is provided, with typical RUN/HALT, RESET, and LTC switches. There are indicators for DC OK and RUN. The RUN lamp is actually an illuminated pushbutton switch, and doubles as the RESET switch.

The bare MLSI-BA11-200 configuration does not contain a LTC, bus termination, powerfail detect/sequencing, or even an interface to the front panel lamps and switches. These functions are provided by the [[MLSI-SMU]], which is a dual-height QBus card. The [[MLSI-SMU]] also provides a pseudo switch register.

QBUS backplanes

2024-07-24T18:33:44Z

Glitch: /* MDB Backplanes */

'''QBUS backplanes''' come mainly in two physical types, [[DEC card form factor|dual-width]] and quad-width. In the quad-width [[backplane]]s, each slot held four 'connectors', DEC's term for a [[DEC edge connector contact identification|group of edge connector pins]], denominated 'A'-'D'.

The [[QBUS]] itself is fully carried in a dual slot, and the quads are further sub-divided into two types, the so-called '''Q/Q''' and '''Q/CD'''. In quad Q/Q units, both sides of each quad slot are fully wired for QBUS, and so a single slot can hold two separate dual-width QBUS [[peripheral controller|devices]]. The device locations are usually arranged for grant priority in so-called 'serpentine' order, i.e. one with the devices in the following kind of order (facing the backplane from the board side):

1-2 4-3 5-6 8-7 9-10

etc (as shown [[:File:BA23 Backplane Grant Continuity.png|here]]).

In a quad Q/CD backplane, the [[DEC edge connector contact identification|CD connectors]] form a private bus, sometimes called the [[CD interconnect]], used to connect together board pairs. (The CD connectors run down the right-hand side, when facing the side of the backplane where the boards plug in, with the CPU at the top.)

It is usually possible to upgrade 18-bit backplanes to 22-bit; see [[Upgrading QBUS backplanes]].

'''''NOTE WELL:''''' For reasons which seem utterly incomprehensible, many boards designed for Q/CD slots (such as [[Private Memory Interconnect|PMI]] cards) '''do not''' avoid the QBUS pins on the CD connectors which contain 'hazardous' (to TTL circuitry) voltages. [''NOTE:'' The exact failure mode here is still not understood; the PMI spec was examined, but no clash of pin assignments was found. The warning is accurate, though: [https://www.ibiblio.org/pub/academic/computer-science/history/pdp-11/hardware/micronotes/numerical/micronote28.txt MicroNote #28] says "MSV11-J MODULES CAN[NOT] BE PLACED IN A Q/Q BACKPLANE SLOT. IF THIS IS ATTEMPTED PERMANENT DAMAGE WILL BE DONE TO THE BOARDS".] So, plugging such a card into a Q/Q backplane will generally '''''destroy''''' the card.

==Backplane types==

Several manufacturers produced QBus compatible backplanes:

===DEC Backplanes===

The following table lists the backplanes produced by [[Digital Equipment Corporation|DEC]]:

{| class="wikitable"
! ID !! Type !! Height || Address Width !! Chassis !! Termination || Comments
|-
| [[H9270 backplane|H9270-A]] || Q/Q || 4 || Q18 || [[BA11-M mounting box|BA11-M]] || none
|-
| [[H9270 backplane|H9270-Q]] || Q/Q || 4 || Q18/Q22 ||  || none
|-
| [[H9273 backplane|H9273]] || Q/CD || 9 || Q18 || [[BA11-N mounting box|BA11-N]] || none
|-
| H9275 || Q/Q || 9 || Q22 ||  || 120 ohms
|-
| [[H9276 backplane|H9276]] || Q/CD || 9 || Q22 || [[BA11-S mounting box|BA11-S]] || none
|-
| [[H9278 backplane|H9278]] || mixed || 8 || Q22 || [[BA23]] || none || slots 1-3 are Q/CD; slots 4-8 are Q/Q; removable termination packs
|-
| [[54-17507 backplane|54-17507]] || mixed || 12+1 || Q22 || [[BA123]] || 120 ohms || slots 1-4 are Q/CD; slots 5-12 are Q/Q; slot 13 provides only power and the [[DCOK Signal]]
|-
| H9281-Q || Q || 4/8/12 || Q18/Q22 ||   || none/120 ohms
|-
| DDV11-B || hex Q/Q || 9 || Q18 || H909-C || none || E-F connectors un-wired
|-
| DDV11-C || hex Q/Q || 4 || Q18 ||   || none || E-F connectors wired as CD interconnect
|}

'Type' indicates whether it is dual-width ('Q') or quad. 'Height' is the number of slots; the number of dual-width board which can be plugged in is twice this, for Q/Q quad backplanes.

The DDV11-C details are somewhat speculative; in the [[VS11 Graphic System|VS11]], it is used with a [[VSV11 Graphic System|VSV11]], and the VSV11's Video Bus is carried over the E-F connectors. Puzzlingly, the VS11 documentation shows that a DDV11-D may also be used - but it claims to have the E-F connectors un-wired.

===MDB Backplanes===

[[MDB Systems]] produced many third-party QBus options, including backplanes and complete chassis systems:

{| class="wikitable"
! ID !! Type !! Width || Address Width !! Assembly || Chassis !! Termination || Comments
|-
| [[40328]] || Q/Q || 8 || Q18 || [[MLSI-BPA84]] || [[MLSI-BA11-200]] || none || Wire wrap pins, can be wrapped to Q22
|}

'Type' indicates slot height and wiring, a value with a slash indicates quad height slots. 'Width' is the number of slots; if the backplane is quad-height, twice as many dual-height modules will fit.

As with DEC backplanes, MDB backplanes that are Q/Q will damage QBus cards with CD interconnects.

==External links==

* [http://www.bitsavers.org/pdf/dec/qbus/Digital_Microcomputer_Products_Handbook_1985.pdf Microcomputer Products Handbook (19850] - backplanes are covered in Part X, 'Backplanes, Enclosures, and Expansion Cables'
* [https://www.ibiblio.org/pub/academic/computer-science/history/pdp-11/hardware/micronotes/numerical/micronote29.txt Q-bus Expansion Concepts] ([[MicroNote]] #029)
* [http://www.douglaspcb.com/ Douglas Electronics] still sells extender cards for DEC backplanes
** [https://www.douglaspcb.com/index.php/6-de-11.html 6-DE-11-C dual extender]
** [https://www.douglaspcb.com/index.php/6-de-8.html 6-DE-8-C quad extender]

[[Category: QBUS Backplanes]]

QBUS backplanes

2024-07-24T18:33:36Z

Glitch: /* MDB Backplanes */

'''QBUS backplanes''' come mainly in two physical types, [[DEC card form factor|dual-width]] and quad-width. In the quad-width [[backplane]]s, each slot held four 'connectors', DEC's term for a [[DEC edge connector contact identification|group of edge connector pins]], denominated 'A'-'D'.

The [[QBUS]] itself is fully carried in a dual slot, and the quads are further sub-divided into two types, the so-called '''Q/Q''' and '''Q/CD'''. In quad Q/Q units, both sides of each quad slot are fully wired for QBUS, and so a single slot can hold two separate dual-width QBUS [[peripheral controller|devices]]. The device locations are usually arranged for grant priority in so-called 'serpentine' order, i.e. one with the devices in the following kind of order (facing the backplane from the board side):

1-2 4-3 5-6 8-7 9-10

etc (as shown [[:File:BA23 Backplane Grant Continuity.png|here]]).

In a quad Q/CD backplane, the [[DEC edge connector contact identification|CD connectors]] form a private bus, sometimes called the [[CD interconnect]], used to connect together board pairs. (The CD connectors run down the right-hand side, when facing the side of the backplane where the boards plug in, with the CPU at the top.)

It is usually possible to upgrade 18-bit backplanes to 22-bit; see [[Upgrading QBUS backplanes]].

'''''NOTE WELL:''''' For reasons which seem utterly incomprehensible, many boards designed for Q/CD slots (such as [[Private Memory Interconnect|PMI]] cards) '''do not''' avoid the QBUS pins on the CD connectors which contain 'hazardous' (to TTL circuitry) voltages. [''NOTE:'' The exact failure mode here is still not understood; the PMI spec was examined, but no clash of pin assignments was found. The warning is accurate, though: [https://www.ibiblio.org/pub/academic/computer-science/history/pdp-11/hardware/micronotes/numerical/micronote28.txt MicroNote #28] says "MSV11-J MODULES CAN[NOT] BE PLACED IN A Q/Q BACKPLANE SLOT. IF THIS IS ATTEMPTED PERMANENT DAMAGE WILL BE DONE TO THE BOARDS".] So, plugging such a card into a Q/Q backplane will generally '''''destroy''''' the card.

==Backplane types==

Several manufacturers produced QBus compatible backplanes:

===DEC Backplanes===

The following table lists the backplanes produced by [[Digital Equipment Corporation|DEC]]:

{| class="wikitable"
! ID !! Type !! Height || Address Width !! Chassis !! Termination || Comments
|-
| [[H9270 backplane|H9270-A]] || Q/Q || 4 || Q18 || [[BA11-M mounting box|BA11-M]] || none
|-
| [[H9270 backplane|H9270-Q]] || Q/Q || 4 || Q18/Q22 ||  || none
|-
| [[H9273 backplane|H9273]] || Q/CD || 9 || Q18 || [[BA11-N mounting box|BA11-N]] || none
|-
| H9275 || Q/Q || 9 || Q22 ||  || 120 ohms
|-
| [[H9276 backplane|H9276]] || Q/CD || 9 || Q22 || [[BA11-S mounting box|BA11-S]] || none
|-
| [[H9278 backplane|H9278]] || mixed || 8 || Q22 || [[BA23]] || none || slots 1-3 are Q/CD; slots 4-8 are Q/Q; removable termination packs
|-
| [[54-17507 backplane|54-17507]] || mixed || 12+1 || Q22 || [[BA123]] || 120 ohms || slots 1-4 are Q/CD; slots 5-12 are Q/Q; slot 13 provides only power and the [[DCOK Signal]]
|-
| H9281-Q || Q || 4/8/12 || Q18/Q22 ||   || none/120 ohms
|-
| DDV11-B || hex Q/Q || 9 || Q18 || H909-C || none || E-F connectors un-wired
|-
| DDV11-C || hex Q/Q || 4 || Q18 ||   || none || E-F connectors wired as CD interconnect
|}

'Type' indicates whether it is dual-width ('Q') or quad. 'Height' is the number of slots; the number of dual-width board which can be plugged in is twice this, for Q/Q quad backplanes.

The DDV11-C details are somewhat speculative; in the [[VS11 Graphic System|VS11]], it is used with a [[VSV11 Graphic System|VSV11]], and the VSV11's Video Bus is carried over the E-F connectors. Puzzlingly, the VS11 documentation shows that a DDV11-D may also be used - but it claims to have the E-F connectors un-wired.

===MDB Backplanes===

[[MDB Systems]] produced many third-party QBus options, including backplanes and complete chassis systems:

{| class="wikitable"
! ID !! Type !! Width || Address Width !! Assembly || Chassis !! Termination || Comments
|-
| [[40328]] || Q/Q || 8 || Q18 || [[MLSI--BPA84]] || [[MLSI-BA11-200]] || none || Wire wrap pins, can be wrapped to Q22
|}

'Type' indicates slot height and wiring, a value with a slash indicates quad height slots. 'Width' is the number of slots; if the backplane is quad-height, twice as many dual-height modules will fit.

As with DEC backplanes, MDB backplanes that are Q/Q will damage QBus cards with CD interconnects.

==External links==

* [http://www.bitsavers.org/pdf/dec/qbus/Digital_Microcomputer_Products_Handbook_1985.pdf Microcomputer Products Handbook (19850] - backplanes are covered in Part X, 'Backplanes, Enclosures, and Expansion Cables'
* [https://www.ibiblio.org/pub/academic/computer-science/history/pdp-11/hardware/micronotes/numerical/micronote29.txt Q-bus Expansion Concepts] ([[MicroNote]] #029)
* [http://www.douglaspcb.com/ Douglas Electronics] still sells extender cards for DEC backplanes
** [https://www.douglaspcb.com/index.php/6-de-11.html 6-DE-11-C dual extender]
** [https://www.douglaspcb.com/index.php/6-de-8.html 6-DE-8-C quad extender]

[[Category: QBUS Backplanes]]

QBUS backplanes

2024-07-24T18:32:13Z

Glitch: /* MDB Backplanes */

'''QBUS backplanes''' come mainly in two physical types, [[DEC card form factor|dual-width]] and quad-width. In the quad-width [[backplane]]s, each slot held four 'connectors', DEC's term for a [[DEC edge connector contact identification|group of edge connector pins]], denominated 'A'-'D'.

The [[QBUS]] itself is fully carried in a dual slot, and the quads are further sub-divided into two types, the so-called '''Q/Q''' and '''Q/CD'''. In quad Q/Q units, both sides of each quad slot are fully wired for QBUS, and so a single slot can hold two separate dual-width QBUS [[peripheral controller|devices]]. The device locations are usually arranged for grant priority in so-called 'serpentine' order, i.e. one with the devices in the following kind of order (facing the backplane from the board side):

1-2 4-3 5-6 8-7 9-10

etc (as shown [[:File:BA23 Backplane Grant Continuity.png|here]]).

In a quad Q/CD backplane, the [[DEC edge connector contact identification|CD connectors]] form a private bus, sometimes called the [[CD interconnect]], used to connect together board pairs. (The CD connectors run down the right-hand side, when facing the side of the backplane where the boards plug in, with the CPU at the top.)

It is usually possible to upgrade 18-bit backplanes to 22-bit; see [[Upgrading QBUS backplanes]].

'''''NOTE WELL:''''' For reasons which seem utterly incomprehensible, many boards designed for Q/CD slots (such as [[Private Memory Interconnect|PMI]] cards) '''do not''' avoid the QBUS pins on the CD connectors which contain 'hazardous' (to TTL circuitry) voltages. [''NOTE:'' The exact failure mode here is still not understood; the PMI spec was examined, but no clash of pin assignments was found. The warning is accurate, though: [https://www.ibiblio.org/pub/academic/computer-science/history/pdp-11/hardware/micronotes/numerical/micronote28.txt MicroNote #28] says "MSV11-J MODULES CAN[NOT] BE PLACED IN A Q/Q BACKPLANE SLOT. IF THIS IS ATTEMPTED PERMANENT DAMAGE WILL BE DONE TO THE BOARDS".] So, plugging such a card into a Q/Q backplane will generally '''''destroy''''' the card.

==Backplane types==

Several manufacturers produced QBus compatible backplanes:

===DEC Backplanes===

The following table lists the backplanes produced by [[Digital Equipment Corporation|DEC]]:

{| class="wikitable"
! ID !! Type !! Height || Address Width !! Chassis !! Termination || Comments
|-
| [[H9270 backplane|H9270-A]] || Q/Q || 4 || Q18 || [[BA11-M mounting box|BA11-M]] || none
|-
| [[H9270 backplane|H9270-Q]] || Q/Q || 4 || Q18/Q22 ||  || none
|-
| [[H9273 backplane|H9273]] || Q/CD || 9 || Q18 || [[BA11-N mounting box|BA11-N]] || none
|-
| H9275 || Q/Q || 9 || Q22 ||  || 120 ohms
|-
| [[H9276 backplane|H9276]] || Q/CD || 9 || Q22 || [[BA11-S mounting box|BA11-S]] || none
|-
| [[H9278 backplane|H9278]] || mixed || 8 || Q22 || [[BA23]] || none || slots 1-3 are Q/CD; slots 4-8 are Q/Q; removable termination packs
|-
| [[54-17507 backplane|54-17507]] || mixed || 12+1 || Q22 || [[BA123]] || 120 ohms || slots 1-4 are Q/CD; slots 5-12 are Q/Q; slot 13 provides only power and the [[DCOK Signal]]
|-
| H9281-Q || Q || 4/8/12 || Q18/Q22 ||   || none/120 ohms
|-
| DDV11-B || hex Q/Q || 9 || Q18 || H909-C || none || E-F connectors un-wired
|-
| DDV11-C || hex Q/Q || 4 || Q18 ||   || none || E-F connectors wired as CD interconnect
|}

'Type' indicates whether it is dual-width ('Q') or quad. 'Height' is the number of slots; the number of dual-width board which can be plugged in is twice this, for Q/Q quad backplanes.

The DDV11-C details are somewhat speculative; in the [[VS11 Graphic System|VS11]], it is used with a [[VSV11 Graphic System|VSV11]], and the VSV11's Video Bus is carried over the E-F connectors. Puzzlingly, the VS11 documentation shows that a DDV11-D may also be used - but it claims to have the E-F connectors un-wired.

===MDB Backplanes===

[[MDB Systems]] produced many third-party QBus options, including backplanes and complete chassis systems:

{| class="wikitable"
! ID !! Type !! Width || Address Width !! Chassis !! Termination || Comments
|-
| [[40328]] || Q/Q || 8 || Q18 || [[MLSI-BA11-200]] || none || Wire wrap pins, can be wrapped to Q22, MLSI BPA-84 when mounted in a card cage
|}

'Type' indicates slot height and wiring, a value with a slash indicates quad height slots. 'Width' is the number of slots; if the backplane is quad-height, twice as many dual-height modules will fit.

As with DEC backplanes, MDB backplanes that are Q/Q will damage QBus cards with CD interconnects.

==External links==

* [http://www.bitsavers.org/pdf/dec/qbus/Digital_Microcomputer_Products_Handbook_1985.pdf Microcomputer Products Handbook (19850] - backplanes are covered in Part X, 'Backplanes, Enclosures, and Expansion Cables'
* [https://www.ibiblio.org/pub/academic/computer-science/history/pdp-11/hardware/micronotes/numerical/micronote29.txt Q-bus Expansion Concepts] ([[MicroNote]] #029)
* [http://www.douglaspcb.com/ Douglas Electronics] still sells extender cards for DEC backplanes
** [https://www.douglaspcb.com/index.php/6-de-11.html 6-DE-11-C dual extender]
** [https://www.douglaspcb.com/index.php/6-de-8.html 6-DE-8-C quad extender]

[[Category: QBUS Backplanes]]

QBUS backplanes

2024-07-24T18:21:58Z

Glitch: Adding MDB Systems backplane subsection, giving DEC backplanes a subsection

'''QBUS backplanes''' come mainly in two physical types, [[DEC card form factor|dual-width]] and quad-width. In the quad-width [[backplane]]s, each slot held four 'connectors', DEC's term for a [[DEC edge connector contact identification|group of edge connector pins]], denominated 'A'-'D'.

The [[QBUS]] itself is fully carried in a dual slot, and the quads are further sub-divided into two types, the so-called '''Q/Q''' and '''Q/CD'''. In quad Q/Q units, both sides of each quad slot are fully wired for QBUS, and so a single slot can hold two separate dual-width QBUS [[peripheral controller|devices]]. The device locations are usually arranged for grant priority in so-called 'serpentine' order, i.e. one with the devices in the following kind of order (facing the backplane from the board side):

1-2 4-3 5-6 8-7 9-10

etc (as shown [[:File:BA23 Backplane Grant Continuity.png|here]]).

In a quad Q/CD backplane, the [[DEC edge connector contact identification|CD connectors]] form a private bus, sometimes called the [[CD interconnect]], used to connect together board pairs. (The CD connectors run down the right-hand side, when facing the side of the backplane where the boards plug in, with the CPU at the top.)

It is usually possible to upgrade 18-bit backplanes to 22-bit; see [[Upgrading QBUS backplanes]].

'''''NOTE WELL:''''' For reasons which seem utterly incomprehensible, many boards designed for Q/CD slots (such as [[Private Memory Interconnect|PMI]] cards) '''do not''' avoid the QBUS pins on the CD connectors which contain 'hazardous' (to TTL circuitry) voltages. [''NOTE:'' The exact failure mode here is still not understood; the PMI spec was examined, but no clash of pin assignments was found. The warning is accurate, though: [https://www.ibiblio.org/pub/academic/computer-science/history/pdp-11/hardware/micronotes/numerical/micronote28.txt MicroNote #28] says "MSV11-J MODULES CAN[NOT] BE PLACED IN A Q/Q BACKPLANE SLOT. IF THIS IS ATTEMPTED PERMANENT DAMAGE WILL BE DONE TO THE BOARDS".] So, plugging such a card into a Q/Q backplane will generally '''''destroy''''' the card.

==Backplane types==

Several manufacturers produced QBus compatible backplanes:

===DEC Backplanes===

The following table lists the backplanes produced by [[Digital Equipment Corporation|DEC]]:

{| class="wikitable"
! ID !! Type !! Height || Address Width !! Chassis !! Termination || Comments
|-
| [[H9270 backplane|H9270-A]] || Q/Q || 4 || Q18 || [[BA11-M mounting box|BA11-M]] || none
|-
| [[H9270 backplane|H9270-Q]] || Q/Q || 4 || Q18/Q22 ||  || none
|-
| [[H9273 backplane|H9273]] || Q/CD || 9 || Q18 || [[BA11-N mounting box|BA11-N]] || none
|-
| H9275 || Q/Q || 9 || Q22 ||  || 120 ohms
|-
| [[H9276 backplane|H9276]] || Q/CD || 9 || Q22 || [[BA11-S mounting box|BA11-S]] || none
|-
| [[H9278 backplane|H9278]] || mixed || 8 || Q22 || [[BA23]] || none || slots 1-3 are Q/CD; slots 4-8 are Q/Q; removable termination packs
|-
| [[54-17507 backplane|54-17507]] || mixed || 12+1 || Q22 || [[BA123]] || 120 ohms || slots 1-4 are Q/CD; slots 5-12 are Q/Q; slot 13 provides only power and the [[DCOK Signal]]
|-
| H9281-Q || Q || 4/8/12 || Q18/Q22 ||   || none/120 ohms
|-
| DDV11-B || hex Q/Q || 9 || Q18 || H909-C || none || E-F connectors un-wired
|-
| DDV11-C || hex Q/Q || 4 || Q18 ||   || none || E-F connectors wired as CD interconnect
|}

'Type' indicates whether it is dual-width ('Q') or quad. 'Height' is the number of slots; the number of dual-width board which can be plugged in is twice this, for Q/Q quad backplanes.

The DDV11-C details are somewhat speculative; in the [[VS11 Graphic System|VS11]], it is used with a [[VSV11 Graphic System|VSV11]], and the VSV11's Video Bus is carried over the E-F connectors. Puzzlingly, the VS11 documentation shows that a DDV11-D may also be used - but it claims to have the E-F connectors un-wired.

===MDB Backplanes===

[[MDB Systems]] produced many third-party QBus options, including backplanes and complete chassis systems:

{| class="wikitable"
! ID !! Type !! Width || Address Width !! Chassis !! Termination || Comments
|-
| [[40328]] || Q/Q || 8 || Q18 || [[MLSI-BA11-200]] || none || Wire wrap pins, can be wrapped to Q22
|}

'Type' indicates slot height and wiring, a value with a slash indicates quad height slots. 'Width' is the number of slots; if the backplane is quad-height, twice as many dual-height modules will fit.

As with DEC backplanes, MDB backplanes that are Q/Q will damage QBus cards with CD interconnects.

==External links==

* [http://www.bitsavers.org/pdf/dec/qbus/Digital_Microcomputer_Products_Handbook_1985.pdf Microcomputer Products Handbook (19850] - backplanes are covered in Part X, 'Backplanes, Enclosures, and Expansion Cables'
* [https://www.ibiblio.org/pub/academic/computer-science/history/pdp-11/hardware/micronotes/numerical/micronote29.txt Q-bus Expansion Concepts] ([[MicroNote]] #029)
* [http://www.douglaspcb.com/ Douglas Electronics] still sells extender cards for DEC backplanes
** [https://www.douglaspcb.com/index.php/6-de-11.html 6-DE-11-C dual extender]
** [https://www.douglaspcb.com/index.php/6-de-8.html 6-DE-8-C quad extender]

[[Category: QBUS Backplanes]]

MSV11-J memory module

2024-07-23T13:00:24Z

Glitch: /* Diagnostics */

[[Image:M8637.jpg|150px|right]]

The '''MSV11-J''' (M8637) is a [[QBUS]]/[[Private Memory Interconnect|PMI]] [[Dynamic RAM|DRAM]] [[main memory]] card. As a PMI card, it uses the [[CD interconnect]]; it can therefore ''only'' be plugged into a [[QBUS#Backplanes|Q/CD backplane]]. '''''NOTE:''''' Plugging an MSV11-J card into a regular [[QBUS#Backplanes|Q/Q backplane]] will '''damage''' the MSV11-J.

It has [[Error-correcting code|ECC]] which automagically corrects single-[[bit]] errors (at a slight penalty in [[access time|response time]] when an error occurs), and detects double-bit errors. It holds 2 Mbytes when fully populated with 256Kx1 DRAM [[integrated circuit|chips]], or 1 Mbyte when half-populated (the only partially-filled configuration allowed). It supports block mode on both the QBUS and PMI.

Although it can function in QBUS-only mode (but see the note below about the -JB and -JC versions), it is really intended for use with a PMI-capable [[Central Processing Unit|CPU]], such as the [[KDJ11-B CPU|KDJ11-B]]. In systems such as the [[PDP-11/83]], where the primary [[Input/output|I/O]] [[bus]] is the QBUS, the card 'speaks' PMI to the CPU, and QBUS to the devices. In the [[PDP-11/84]], PMI is used for communication with both the CPU and the devices (via the [[KTJ11-B UNIBUS adapter]]).

The memory is arranged as 2 banks, each 16 data bits wide, with 6 additional bits for the ECC. One bank is used to hold [[word]]s at even word locations, the other for those in odd; the banks are thus [[memory interleaving|interleaved]]. A read cycle from the bus will start a read of both sides simultaneously, and so in PMI mode, the second word is already available once the first has been sent.

On power-on, the system is frozen (via negation of the BPOK QBUS signal) while the entire memory is cleared, to prevent spurious ECC errors. For [[diagnostic]] purposes, the ECC can be disabled, and there are also means for the CPU to read/write the ECC bits directly.

Four versions exist:

* MSV11-JB, 1 Mbyte
* MSV11-JC, 2 Mbyte
* MSV11-JD, 1 Mbyte
* MSV11-JE, 2 Mbyte

The -JB and -JC are earlier versions, which contain an error which prevents them working properly as QBUS memories (i.e. in the PDP-11/83); they are only usable in the PDP-11/84.

==Odd factoids==

When used with a KDJ11-B, the [[bootstrap]] code in its EEPROMs insists that the ECC bits are all wholly functional, otherwise it will stop with an "Error 47 - Memory CSR Error". This happens even though the board will return correct values if the main data DRAMs are fine for the locations with bad ECC bits, and the code ''will'' accept boards with bad data bits!

When the board is in diagnostic mode, it displays an unusual error where some values (''exactly'' 25% of the 2^16) cannot be correctly written and read back. The values affected are consistent across several boards, so this is not due to component variation. The reason, and rationale (if it is not simply a bug), are currently unknown.

==Control Register==

Each board has a single control [[register]], which can be configured in the range 172100-172136.

In the register contents (below), all the bits can be read and written by [[software]]; most are cleared by power up and bus INIT, except the multi-function (address/CRC) bits. Bits which can only be modified by the CPU are shown in normal font, and those which can also be set by the [[hardware]] in ''italics''.

{{16bit-header}}
| ''Uncorrected error'' || Extended address || Set inhibit mode || Reserved || colspan=7 | ''Multi-function'' || ''Single error'' || Inhibit mode pointer || Diagnostic mode || Disable correction || Error indication
{{16bitoctal-bitout}}

The multi-function field contents depend on what is being done; it is used to hold the address of an error; and also to read, and in diagnostic mode write, the ECC bits (called 'syndrome' when read, and 'check' when written).

When it holds the low address (the low/high choice is controlled by bit 14), it holds address bits 11 through 17; when it holds the high address, bits 21 through 18, and in register bit 9, address bit 1 (to tell which bank the error was in) - bits 11-10 are unused.

When it holds the ECC bits, this is the mapping from CSR bits to ECC bits:

{| class="wikitable"
! CSR bit !! Syndrome!!| Check
|-
| 040 || CBx || Snx
|-
| 0100 || CB0 || Sn0
|-
| 0200 || CB1 || Sn1
|-
| 0400 || CB2 || Sn2
|-
| 01000 || CB4 || Sn4
|-
| 02000 || CB8 || Sn8
|}

==Technical information==

As far as is known, there are no engineering drawings extant for the MSV11-J. However, some technical information, enough to [[repairing un-documented MOS memory boards|repair boards with faulty DRAM chips]], has been gathered on it, and that is made available here.

To start with, unlike other [[Digital Equipment Corporation|DEC]] boards, this board does not contain the ''Exx'' identification numbers for chips on the board. The following scheme has therefore been devised, to identify the DRAM chips for the bit to chip table below.

The DRAM chips are organized into four blocks; blocks 0 and 2 hold words in the even-numbered word bank, and 1 and 3 hold those in the odd-numbered word bank. With the component side of the board facing, and the metal insertion handle at the top, the pair of low-address blocks (0 and 1) are at the top of the card, and the optional pair of high-address blocks (2 and 3) are at the bottom.

The low half of the even-numbered word bank (block 0) is on the right side (denoted with an 'R'), and the low half of the odd bank (block 1) on the left ('L'). (Confusingly, the high half has the sides reversed, so that block 2 is on the left, and 3 on the right.) There are three columns on each side (denoted '0'-'2', with the '0' column at the left of each group). Each column contains 17 chips (denoted '0'-'16', with '0' at the top).

Chips are identified as SCRr, where 'S' is the side ('L' or 'R'), C is the column, and 'Rr' is the row. Note that not all the chips in this area are DRAM; for example, in block 1, chips L17, L27, L211, and L213 and up, are not DRAM.

{| class="wikitable"
! Bit !! Block 0 !! Block 1 !! Block 2 !! Block 3
|-
| 01 || R05 || L02 || L010 || R213
|-
| 02 || R14 || L12 || L110 || R113
|-
| 04 || R24 || L22 || L210 || R212
|-
| 10 || R04 || L03 || L011 || R012
|-
| 20 || R13 || L13 || L111 || R112
|-
| 40 || R23 || L23 || L212 || R211
|-
| 100 || R03 || L04 || L012 || R111
|-
| 200 || R22 || L14 || L112 || R210
|-
| 400 || R12 || L24 || L113 || R110
|-
| 1000 || R02 || L05 || L013 || R010
|-
| 2000 || R21 || L15 || L014 || R29
|-
| 4000 || R11 || L25 || L115 || R19
|-
| 10000 || R01 || L06 || L015 || R09
|-
| 20000 || R20 || L16 || L116 || R28
|-
| 40000 || R10 || L26 || L114 || R18
|-
| 100000 || R00 || L07 || L016 || R08
|-
| CBx || R25 || L21 || L29 || R214
|-
| CB0 || R27 || L00 || L08 || R216
|-
| CB1 || R26 || L10 || L18 || R215
|-
| CB2 || R16 || L20 || L28 || R014
|-
| CB4 || R06 || L01 || L09 || R013
|-
| CB8 || R15 || L11 || L19 || R114
|}

''Note:'' When a DRAM chip is removed, if the affected memory location is then read, that bit will be ''high'' (1), not ''low'' (0); the affected input (apparently separate pins for the low and high banks) must float to 1 when there is no DRAM chip present to drive the input.

The following DRAM chips have been observed to be used: MT1259-12 (Micron Technologies), HM50256-15 (Hitachi), NEC 41256 (NEC Electronics), TMS4256-15NL (Texas Instruments), MB81256-15 (Fujitsu).

Note that some of these parts are 120 nsec parts, while others are 150 nsec; the faster parts do not seem to be necessary, or give any advantage.

==Markings==

<pre>
On the board

M8637
Side 1
L1
50-15672-01 C1
Ga6618
2644711
2 MB Q,P-BUS MOS MEM
LPWR
TPB
D.V0

On the metal frame

P/N 1213113
M8637
EC

ASICs on board are 21-24404-01 and 21-22772-01
</pre>

==Diagnostics==

The correct [[XXDP]] exerciser is '''VMJAB0''' which is specific to the MSV11-J and fully compatible boards, such as the [[Clearpoint]] [[QED1]]. '''VMSAC0''' should not be used with a MSV11-J.

During exercising with '''VMJAB0''', it is normal for the red ECC error light to pulse or flicker. It should not stay on.

[[AK6DN]] diagnostic '''MEMX''' will run correctly on the MSV11-J, but may take longer to expose faults, especially offboard faults that only occur during heavy loading, such as failing KDJ11 cache.

==See also==

* [[MSV11-R memory module]]

==External links==

* [http://www.bitsavers.org/pdf/dec/qbus/EK-MSV1J-UG_001_May85.pdf MSV11-J MOS Memory User's Guide] (EK-MSV1J-UG-001)
* [http://www.ibiblio.org/pub/academic/computer-science/history/pdp-11/hardware/micronotes/numerical/micronote28.txt MSV11-Q/M/J Memory Comparisons] (MicroNote 28) - confirms that the -JB/-JC versions will not work reliably on the QBUS
* [http://www.ibiblio.org/pub/academic/computer-science/history/pdp-11/hardware/micronotes/numerical/micronote30.txt Private Memory Management Between the KDJ11-B and the MSV11-J] (MicroNote 30)

[[Category: QBUS Memories]]
[[Category: PMI Memories]]

MSV11-J memory module

2024-07-23T12:59:32Z

Glitch: Adding MSV11-J diagnostics information

[[Image:M8637.jpg|150px|right]]

The '''MSV11-J''' (M8637) is a [[QBUS]]/[[Private Memory Interconnect|PMI]] [[Dynamic RAM|DRAM]] [[main memory]] card. As a PMI card, it uses the [[CD interconnect]]; it can therefore ''only'' be plugged into a [[QBUS#Backplanes|Q/CD backplane]]. '''''NOTE:''''' Plugging an MSV11-J card into a regular [[QBUS#Backplanes|Q/Q backplane]] will '''damage''' the MSV11-J.

It has [[Error-correcting code|ECC]] which automagically corrects single-[[bit]] errors (at a slight penalty in [[access time|response time]] when an error occurs), and detects double-bit errors. It holds 2 Mbytes when fully populated with 256Kx1 DRAM [[integrated circuit|chips]], or 1 Mbyte when half-populated (the only partially-filled configuration allowed). It supports block mode on both the QBUS and PMI.

Although it can function in QBUS-only mode (but see the note below about the -JB and -JC versions), it is really intended for use with a PMI-capable [[Central Processing Unit|CPU]], such as the [[KDJ11-B CPU|KDJ11-B]]. In systems such as the [[PDP-11/83]], where the primary [[Input/output|I/O]] [[bus]] is the QBUS, the card 'speaks' PMI to the CPU, and QBUS to the devices. In the [[PDP-11/84]], PMI is used for communication with both the CPU and the devices (via the [[KTJ11-B UNIBUS adapter]]).

The memory is arranged as 2 banks, each 16 data bits wide, with 6 additional bits for the ECC. One bank is used to hold [[word]]s at even word locations, the other for those in odd; the banks are thus [[memory interleaving|interleaved]]. A read cycle from the bus will start a read of both sides simultaneously, and so in PMI mode, the second word is already available once the first has been sent.

On power-on, the system is frozen (via negation of the BPOK QBUS signal) while the entire memory is cleared, to prevent spurious ECC errors. For [[diagnostic]] purposes, the ECC can be disabled, and there are also means for the CPU to read/write the ECC bits directly.

Four versions exist:

* MSV11-JB, 1 Mbyte
* MSV11-JC, 2 Mbyte
* MSV11-JD, 1 Mbyte
* MSV11-JE, 2 Mbyte

The -JB and -JC are earlier versions, which contain an error which prevents them working properly as QBUS memories (i.e. in the PDP-11/83); they are only usable in the PDP-11/84.

==Odd factoids==

When used with a KDJ11-B, the [[bootstrap]] code in its EEPROMs insists that the ECC bits are all wholly functional, otherwise it will stop with an "Error 47 - Memory CSR Error". This happens even though the board will return correct values if the main data DRAMs are fine for the locations with bad ECC bits, and the code ''will'' accept boards with bad data bits!

When the board is in diagnostic mode, it displays an unusual error where some values (''exactly'' 25% of the 2^16) cannot be correctly written and read back. The values affected are consistent across several boards, so this is not due to component variation. The reason, and rationale (if it is not simply a bug), are currently unknown.

==Control Register==

Each board has a single control [[register]], which can be configured in the range 172100-172136.

In the register contents (below), all the bits can be read and written by [[software]]; most are cleared by power up and bus INIT, except the multi-function (address/CRC) bits. Bits which can only be modified by the CPU are shown in normal font, and those which can also be set by the [[hardware]] in ''italics''.

{{16bit-header}}
| ''Uncorrected error'' || Extended address || Set inhibit mode || Reserved || colspan=7 | ''Multi-function'' || ''Single error'' || Inhibit mode pointer || Diagnostic mode || Disable correction || Error indication
{{16bitoctal-bitout}}

The multi-function field contents depend on what is being done; it is used to hold the address of an error; and also to read, and in diagnostic mode write, the ECC bits (called 'syndrome' when read, and 'check' when written).

When it holds the low address (the low/high choice is controlled by bit 14), it holds address bits 11 through 17; when it holds the high address, bits 21 through 18, and in register bit 9, address bit 1 (to tell which bank the error was in) - bits 11-10 are unused.

When it holds the ECC bits, this is the mapping from CSR bits to ECC bits:

{| class="wikitable"
! CSR bit !! Syndrome!!| Check
|-
| 040 || CBx || Snx
|-
| 0100 || CB0 || Sn0
|-
| 0200 || CB1 || Sn1
|-
| 0400 || CB2 || Sn2
|-
| 01000 || CB4 || Sn4
|-
| 02000 || CB8 || Sn8
|}

==Technical information==

As far as is known, there are no engineering drawings extant for the MSV11-J. However, some technical information, enough to [[repairing un-documented MOS memory boards|repair boards with faulty DRAM chips]], has been gathered on it, and that is made available here.

To start with, unlike other [[Digital Equipment Corporation|DEC]] boards, this board does not contain the ''Exx'' identification numbers for chips on the board. The following scheme has therefore been devised, to identify the DRAM chips for the bit to chip table below.

The DRAM chips are organized into four blocks; blocks 0 and 2 hold words in the even-numbered word bank, and 1 and 3 hold those in the odd-numbered word bank. With the component side of the board facing, and the metal insertion handle at the top, the pair of low-address blocks (0 and 1) are at the top of the card, and the optional pair of high-address blocks (2 and 3) are at the bottom.

The low half of the even-numbered word bank (block 0) is on the right side (denoted with an 'R'), and the low half of the odd bank (block 1) on the left ('L'). (Confusingly, the high half has the sides reversed, so that block 2 is on the left, and 3 on the right.) There are three columns on each side (denoted '0'-'2', with the '0' column at the left of each group). Each column contains 17 chips (denoted '0'-'16', with '0' at the top).

Chips are identified as SCRr, where 'S' is the side ('L' or 'R'), C is the column, and 'Rr' is the row. Note that not all the chips in this area are DRAM; for example, in block 1, chips L17, L27, L211, and L213 and up, are not DRAM.

{| class="wikitable"
! Bit !! Block 0 !! Block 1 !! Block 2 !! Block 3
|-
| 01 || R05 || L02 || L010 || R213
|-
| 02 || R14 || L12 || L110 || R113
|-
| 04 || R24 || L22 || L210 || R212
|-
| 10 || R04 || L03 || L011 || R012
|-
| 20 || R13 || L13 || L111 || R112
|-
| 40 || R23 || L23 || L212 || R211
|-
| 100 || R03 || L04 || L012 || R111
|-
| 200 || R22 || L14 || L112 || R210
|-
| 400 || R12 || L24 || L113 || R110
|-
| 1000 || R02 || L05 || L013 || R010
|-
| 2000 || R21 || L15 || L014 || R29
|-
| 4000 || R11 || L25 || L115 || R19
|-
| 10000 || R01 || L06 || L015 || R09
|-
| 20000 || R20 || L16 || L116 || R28
|-
| 40000 || R10 || L26 || L114 || R18
|-
| 100000 || R00 || L07 || L016 || R08
|-
| CBx || R25 || L21 || L29 || R214
|-
| CB0 || R27 || L00 || L08 || R216
|-
| CB1 || R26 || L10 || L18 || R215
|-
| CB2 || R16 || L20 || L28 || R014
|-
| CB4 || R06 || L01 || L09 || R013
|-
| CB8 || R15 || L11 || L19 || R114
|}

''Note:'' When a DRAM chip is removed, if the affected memory location is then read, that bit will be ''high'' (1), not ''low'' (0); the affected input (apparently separate pins for the low and high banks) must float to 1 when there is no DRAM chip present to drive the input.

The following DRAM chips have been observed to be used: MT1259-12 (Micron Technologies), HM50256-15 (Hitachi), NEC 41256 (NEC Electronics), TMS4256-15NL (Texas Instruments), MB81256-15 (Fujitsu).

Note that some of these parts are 120 nsec parts, while others are 150 nsec; the faster parts do not seem to be necessary, or give any advantage.

==Markings==

<pre>
On the board

M8637
Side 1
L1
50-15672-01 C1
Ga6618
2644711
2 MB Q,P-BUS MOS MEM
LPWR
TPB
D.V0

On the metal frame

P/N 1213113
M8637
EC

ASICs on board are 21-24404-01 and 21-22772-01
</pre>

==Diagnostics==

The correct [[XXDP]] exerciser is '''VMJAB0''' which is specific to the MSV11-J and fully compatible boards, such as the [[Clearpoint]] [[QED1]]. '''VMSAC0''' should not be used with a MSV11-J.

During exercising with '''VMJAB0''', it is normal for the red ECC error light to illuminate briefly. It should not stay on.

[[AK6DN]] diagnostic '''MEMX''' will run correctly on the MSV11-J, but may take longer to expose faults, especially offboard faults that only occur during heavy loading, such as failing KDJ11 cache.

==See also==

* [[MSV11-R memory module]]

==External links==

* [http://www.bitsavers.org/pdf/dec/qbus/EK-MSV1J-UG_001_May85.pdf MSV11-J MOS Memory User's Guide] (EK-MSV1J-UG-001)
* [http://www.ibiblio.org/pub/academic/computer-science/history/pdp-11/hardware/micronotes/numerical/micronote28.txt MSV11-Q/M/J Memory Comparisons] (MicroNote 28) - confirms that the -JB/-JC versions will not work reliably on the QBUS
* [http://www.ibiblio.org/pub/academic/computer-science/history/pdp-11/hardware/micronotes/numerical/micronote30.txt Private Memory Management Between the KDJ11-B and the MSV11-J] (MicroNote 30)

[[Category: QBUS Memories]]
[[Category: PMI Memories]]

QBUS memories

2024-07-19T19:01:16Z

Glitch: Adding Monolithic Systems QBus MOS memories

'''[[QBUS]] memory''' cards are available both from [[Digital Equipment Corporation|DEC]], and from a large number of outside vendors who produced and sold QBUS [[main memory]] cards.

Like the QBUS itself, QBUS memory cards can be divided into [[QBUS#Variable address size|Q16]], Q18 and Q22 memories. In addition, DEC later specified the [[Private Memory Interconnect|PMI]] memory bus, an extension of the QBUS, and some memory cards have dual QBUS/PMI capability.

==Using Q18 memory in Q22 machines==

Note that although Q18 memory cards can be plugged into a Q22 machine (e.g. most [[PDP-11/23]]'s, and all [[PDP-11/73|-11/73]]'s), and seem to work, they will not always function properly, and may cause subtle errors. (The sole exception to this rule is in machines with less than 256KB memory, total.)

This is because a Q18 memory configured for 000000 and up will also respond to bus cycles to 01000000 and up, 02000000 and up, etc.

==Diagnosing DRAM memory failures==

If a memory card has multiple banks of [[integrated circuit|chips]] (e.g. a board built with 64Kx1 chips, so that with the need for a minimum of 16 chips to produce [[word]]-wide memory, if it has 32 chips, or two complete banks, for a total capacity of 256KB), and one bank is picking or dropping bit(s), and the other(s) is/are not, that meant that [[data path]]s are all OK, and it is a simple matter of finding the bad memory chip(s).

This [[diagnostic]] heuristic is quite useful, since many QBUS semiconductor memory cards have (because of the storage size of [[Dynamic RAM|DRAM]] chips, and QBUS cards) two or more banks of nnKx1 chips; so if such a memory card has dropped/picked bits, look to see if all banks have the same fault. If 'no', it's pretty much guaranteed to be a memory chip, and it should be easy to find and fix.

It is possible to repair memory cards with this failure mode without doing any hardware debugging at all; the symptoms, and the memory chip layout (given in the pages for many of the cards listed below), are all one needs. See [[Repairing un-documented MOS memory boards]] for more.

==DEC==

===Core memory===

* [[MMV11-A QBUS core memory|MMV11-A]] - 8-Kbyte unit (H653 and H223)

===MOS memory===

* [[MSV11-A static MOS memory|MSV11-A]] - 2-Kbyte ([[static RAM]])
* [[MSV11-B MOS memory|MSV11-B]] - 8-Kbyte (external [[memory refresh|refresh]] - M7944)
* [[MSV11-C MOS memory|MSV11-C]] - (on-board refresh - M7955)
** MSV11-CA - 8-Kbyte
** MSV11-CB - 16-Kbyte
** MSV11-CC - 24-Kbyte
** MSV11-CD - 32-Kbyte
* [[MSV11-D/E MOS memory|MSV11-D]] - (no [[parity]] - M8044)
** MSV11-DA - 8-Kbyte
** MSV11-DB - 16-Kbyte
** MSV11-DC - 32-Kbyte
** MSV11-DD - 64-Kbyte
* [[MSV11-D/E MOS memory|MSV11-E]] - (parity - M8045)
** MSV11-EA - 8-Kbyte
** MSV11-EB - 16-Kbyte
** MSV11-EC - 32-Kbyte
** MSV11-ED - 64-Kbyte
* [[MSV11-L MOS Random-Access Memory‎|MSV11-L]] - (M8059)
** MSV11-LF - 128-Kbyte
** MSV11-LK - 256-Kbyte
* [[MSV11-M QBUS memory|MSV11-M]] - (M7506)
** MSV11-MA - 512-Kbyte
** MSV11-MB - 1-Mbyte
* [[MSV11-P MOS Random-Access Memory‎|MSV11-P]] - (M8067)
** MSV11-PF - 128-Kbyte
** MSV11-PK - 256-Kbyte
** MSV11-PL - 512-Kbyte
* [[MSV11-Q QBUS memory|MSV11-Q]] - (M7551)
** MSV11-QA - 1-Mbyte
** MSV11-QB - 2-Mbyte
** MSV11-QC - 4-Mbyte
** MSV11-SA - 2-Mbyte

===PMI MOS memory===

PMI memories can generally also function as QBUS memories, except that they cannot be used in a [[QBUS#Backplanes|Q/Q backplane]].

* [[MSV11-J memory module|MSV11-J]] - (ECC, M8637)
** MSV11-JB - 1-Mbyte (no QBUS)
** MSV11-JC - 2-Mbyte (no QBUS)
** MSV11-JD - 1-Mbyte
** MSV11-JE - 2-Mbyte
* [[MSV11-R memory module|MSV11-R]] - 1-Mbyte (parity, M7458)

==Camintonn==

* [[CMV-250]] - 256-Kbyte
* [[CMV-500]] - 512-KByte
* [[CMV-254]] - 1-MByte
* [[CMV-504]] - 2-MByte
* [[CMV-1000]] - 1-MByte
* [[CMV-4000]] - 4-MByte

==Clearpoint==

===MOS memory===

* [[Q-RAM 11]]
** Q-RAM 11-3 - 256-Kbyte, no parity
** Q-RAM 11-3 - 256-Kbyte, parity
** Q-RAM 11-1 - 512-Kbyte, no parity
** Q-RAM 11 - 512-Kbyte, parity
* [[Q-RAM 22B]]
** Q-RAM 22(B)-3 - 512-Kbyte, no parity
** Q-RAM 22(B)-3 - 512-Kbyte, parity
** Q-RAM 22(B)-1 - 1-Mbyte, no parity
** Q-RAM 22(B) - 1-Mbyte, parity
* [[Q-RAM 88B]]
** Q-RAM 88B-2 - 2-Mbyte
** Q-RAM 88B - 4-Mbyte
* [[DCME-Q2A]]
** DCME-Q2A/256KB
** DCME-Q2A/512KB
* [[DCME-Q2B]] - 256-Kbyte / 512-Kbyte / 1-Mbyte / 2-Mbyte
** DCME-Q2B/256KB
** DCME-Q2B/512KB
** DCME-Q2B/1MB
** DCME-Q2B/2MB
* [[DCME-Q4B]]
** DCME-Q4B/512KB
** DCME-Q4B/1MB
** DCME-Q4B/2MB
** DCME-Q4B/4MB

===PMI MOS memory===

* [[QED1]] (aka QED-F) - 2-Mbyte / 4-Mbyte
* [[DCME-Q4E]] - 2-Mbyte / 4-Mbyte

==Monolithic Systems==

* [[MSC 4601]] - 64 Kbyte
* [[MSC 303-0289]] - 256 Kbyte, parity
* [[MSC 303-0339]] - 1 Mbyte, parity

==Mostek==

* [[Mostek MK8022|MK8022]] - 256-Kbyte

==National Semiconductor==

* [[National Semiconductor NS23C QBUS memory|NS23C]] - 128-Kbyte / 256-KByte / 1-Mbyte, parity
* [[National Semiconductor NS23M QBUS memory|NS23M]] - 256-Kbyte, parity
* [[NS23S]] - 1-Mbyte, parity

==See also==

* [[PMI memories]]
* [[Repairing un-documented MOS memory boards]]

==External links==

* [http://web.frainresearch.org:8080/projects/pdp-11/memory.php Read/Write Memory Modules]

[[Category: QBUS Memories]]
[[Category: DEC Memories]]

BA23 Enclosure

2024-07-19T12:38:22Z

Glitch: /* BA23 H9278 Backplane */

[[File:BA23 Enclosure Pedestal Version (MicroVAX).png|350px|thumb|right|BA23 Enclosure Pedestal Version (MicroVAX)]]

The '''BA23 Enclosure''' is a [[QBUS]] [[mounting box]] from [[Digital Equipment Corporation|DEC]] which is available in pedestal, table-top, and rack mount versions. There is also a 'bigger brother', the [[BA123]] enclosure.

The BA23 is the successor to the [[BA11-M mounting box|BA11-M]] QBUS mounting box.

The BA23 enclosure is famous for the risk to skin one's knuckles - it is packed inside very tightly.

==BA23 Usage==

The BA23 enclosure was used for the following DEC [[PDP-11]], [[VAXstation]], and [[MicroVAX]] computers:

* [[PDP-11/23+]]
* [[PDP-11/53]]
* [[PDP-11/73]]
* [[PDP-11/83]]
* [[PDP-11/93]]

* [[MicroVAX I]]
* [[VAXstation I]]
* [[MicroVAX II]]
* [[VAXstation II]]
* [[VAXstation 3200/3500 | VAXstation 3200]]

Some versions of the computers listed above were also available in the BA123 enclosure, or in the [[H9642]] Medium System Cabinet.

The H9642 Medium System Cabinet contains two BA23 enclosures, one 'Standard' BA23-A, and one 'Expander' BA23-C.

In the cabinet both BA23 enclosures are connected with a [[BCV2A]] 'Qbus expansion cable and terminator BA23A to BA23C' to provide a large Qbus configuration.

==BA23 Mass Storage Device Areas==

[[File:BA23 Mass Storage Locations.png|300px|thumb|left|BA23 Mass Storage Locations A & B]]

The BA23 can hold full-height and half-height 13.3 cm (5.25 in) mass storage devices, depending on the system.

You can install one [[RD5x-series]] fixed-disk drive and one removable-media drive — an [[RX50]] diskette drive or a [[TK50]] tape drive.
You cannot install two full-height, fixed-disk drives due to power limitations.

You can connect external drives to the system’s I/O distribution panel.

The number of drives you can use depends on the space available in the I/O panel and backplane, and the amount of power available to run the drive controllers.

 

==BA23 Control Panel==

The BA23 has either a 4- or 6-button control panel as follows:

[[File:BA23 4-Button Control Panel and PC Board (Example).png|300px|thumb|right|BA23 4-Button Control Panel and PC Board (Example)]]

Systems with a 4-button control panel support only full-height mass storage devices.

 

[[File:BA23 6-Button Control Panel and PC Board (Example).png|300px|thumb|right|BA23 6-Button Control Panel and PC Board (Example)]]

Systems with a 6-button control panel support either full-height or half-height devices.

 

==BA23 Signal Distribution Panel==

[[File:BA23 Signal Distribution Panel.png|300px|thumb|left|BA23 Signal Distribution Panel]]

The signal distribution panel carries signals from an [[RQDX1/RQDX2 MFM Disk & Floppy QBUS Controllers|RQDX1]], [[RQDX1/RQDX2 MFM Disk & Floppy QBUS Controllers|RQDX2]], or [[RQDX3 MFM Disk & Floppy QBUS Controller|RQDX3]] controller module in the [[QBUS#Variable_address_size|Q22-bus]] backplane to the mass storage devices.

 

==BA23 H9278 Backplane==

[[File:BA23 Backplane Grant Continuity.png|350px|thumb|right|BA23 H9278 Qbus Backplane Grant Continuity]]

The BA23 enclosure contains the [[QBUS_backplanes#Backplane types|H9278]] Qbus [[backplane]].

The picture shows the H9278 Qbus Backplane [[bus grant]] continuity.

Slots 1-3 are Q/CD; slots 4-8 are Q/Q

 

===Termination===

The BA23 backplane includes removable SIP termination resistors at the bottom. Termination may be 120 ohms or 240 ohms, depending on processor board. Per [[DEC MicroNote 35, "Q-bus Expansion Concepts"]], these termination packs are removed when an expansion chassis is used with the BA23. Keep this in mind when separating an expanded QBus system!

==BA23 Internal Cabling==

[[File:BA23 Internal Cabling (Example).png|300px|thumb|left|BA23 Internal Cabling (Example)]]

 

==BA23 H7864 Power Supply==

[[File:BA23 Power Supply.png|300px|thumb|right|BA23 H7864 Power Supply]]

There are three variations of the BA23 [[power supply]], depending on the enclosure model number:
H7864, H7864A, or H7864B.

The power supply regulators maintain proper output [[voltage]]s against temporary fluctuations in the ac input to the power supply.

The power supply is a 230 W unit. It supplies +5 Vdc at 4.5 amps (A) to 36.0 A, and +12 Vdc at 0.0 A to 7.0 A to the following system components:

* Backplane
* Fixed-disk drive
* Diskette drive or tape drive

 

The power supply also sends three system control signals to the backplane, asserting two of these signals (BDCOK H and BPOK H) when the system power is stable.
The third signal (BEVENT L) is an external line clock interrupt request to the CPU. The LTC switch on the control panel PC board enables the BEVENT signal.

The power supply also has two +10 Vdc at 0.45 A fan outputs for the front and rear dc fans.
You can increase the fan voltages to +12 Vdc by changing a power supply jumper.
The [[KA630]] CPU module’s thermal and acoustical specifications for example, are based on the +10 volt setting.
The required fan power does not affect the 230 W output.

=== Capacitor Issues ===

The BA23 power supply contains one or more RIFA capacitors, which should be replaced before operation. These capacitors fail due to moisture ingress from cracks in the encapsulation. They release great quantities of smoke when they fail.

The BA23 power supply assembly AA12131, manufactured by Aztec, has been found with leaking general purpose and low ESR capacitors, and should be recapped when disassembled for RIFA replacement. The large capacitors in the fan supply circuit generally do not require replacement, nor do the bulk capacitors immediately after the AC line rectifiers. A capacitor list has been provided in the External Links section.

==BA23 I/O Panel==

[[File:BA23 I-O Panel.png|300px|thumb|right|BA23 I/O Panel Adapter plate with typical type A and B inserts]]

You use the I/O panel to connect external devices to the system.

Each device connects to a module in the system through a filtered connector.

You mount the connector on an insert, then install the insert in a cutout on the I/O panel.

Filtered connectors and inserts are part of the option’s cabinet kit.

Usually, the CPU insert is installed in the top (or left) cutout.

The I/O panel has six cutouts in two sizes, types A and B.

 

{| class="wikitable" style="text-align:center;"
! colspan="5" | BA23 I/O Panel Cutout and Insert Sizes
|-
| Type || Quantity || C/I || Inches || Millimeters
|-
| A || 2 || Cutout || 0.6 x 3.2 || 15 x 81
|-
| A || 2 || Insert || 1.0 x 4.0 || 25 x 102
|-
| B || 4 || Cutout || 2.25 x 3.2 || 57 x 81
|-
| B || 4 || Insert || 2.5 x 3.3 || 64 x 84
|}

You can install three more type A inserts by removing the bracket between the third and fourth cutouts and installing an adapter plate.

==Cooling Considerations==

The BA23 uses an airflow path which pulls cooling air through the card cage, into the [[power supply]], and exhausts it through the top (in vertical orientation) or left (horizontal orientation, from the front) side of the chassis through two 120V 120mm fans. The fan closest to the rear of the chassis is mostly responsible for power supply and [[QBus]] card cage cooling, the fan closest to the front of the chassis handles storage area cooling.

Operating the BA23 with the I/O panel removed may reduce cooling efficiency, leading to hot running or overheating when running programs which stress the system, such as the [[XXDP]] '''VMJAB0''' memory exerciser, especially in configurations that include a [[KDJ11-B]]. The intake side of the chassis should be kept free from obstructions during operation, as the fans in the output side will pull intake air from the path of least resistance.

When operating the BA23 in a rack mounted configuration, ensure adequate intake and exhaust airflow. This often precludes the use of rack side skins.

==External links==

* [http://bitsavers.trailing-edge.com/scandocs.trailing-edge.com/micropdp11-volume_2_enclosures-EK-186AA-MG-001.pdf BA23 Enclosure Maintenance] (EK-186AA-MG-001)
* [http://filedump.glitchwrks.com/cap_lists/dec_ba23_aa12131.pdf DEC BA23 AA12131 Power Supply Capacitor List]

[[Category: DEC Mounting Boxes]]

BA23 Enclosure

2024-07-19T12:31:04Z

Glitch: /* Cooling Considerations */

[[File:BA23 Enclosure Pedestal Version (MicroVAX).png|350px|thumb|right|BA23 Enclosure Pedestal Version (MicroVAX)]]

The '''BA23 Enclosure''' is a [[QBUS]] [[mounting box]] from [[Digital Equipment Corporation|DEC]] which is available in pedestal, table-top, and rack mount versions. There is also a 'bigger brother', the [[BA123]] enclosure.

The BA23 is the successor to the [[BA11-M mounting box|BA11-M]] QBUS mounting box.

The BA23 enclosure is famous for the risk to skin one's knuckles - it is packed inside very tightly.

==BA23 Usage==

The BA23 enclosure was used for the following DEC [[PDP-11]], [[VAXstation]], and [[MicroVAX]] computers:

* [[PDP-11/23+]]
* [[PDP-11/53]]
* [[PDP-11/73]]
* [[PDP-11/83]]
* [[PDP-11/93]]

* [[MicroVAX I]]
* [[VAXstation I]]
* [[MicroVAX II]]
* [[VAXstation II]]
* [[VAXstation 3200/3500 | VAXstation 3200]]

Some versions of the computers listed above were also available in the BA123 enclosure, or in the [[H9642]] Medium System Cabinet.

The H9642 Medium System Cabinet contains two BA23 enclosures, one 'Standard' BA23-A, and one 'Expander' BA23-C.

In the cabinet both BA23 enclosures are connected with a [[BCV2A]] 'Qbus expansion cable and terminator BA23A to BA23C' to provide a large Qbus configuration.

==BA23 Mass Storage Device Areas==

[[File:BA23 Mass Storage Locations.png|300px|thumb|left|BA23 Mass Storage Locations A & B]]

The BA23 can hold full-height and half-height 13.3 cm (5.25 in) mass storage devices, depending on the system.

You can install one [[RD5x-series]] fixed-disk drive and one removable-media drive — an [[RX50]] diskette drive or a [[TK50]] tape drive.
You cannot install two full-height, fixed-disk drives due to power limitations.

You can connect external drives to the system’s I/O distribution panel.

The number of drives you can use depends on the space available in the I/O panel and backplane, and the amount of power available to run the drive controllers.

 

==BA23 Control Panel==

The BA23 has either a 4- or 6-button control panel as follows:

[[File:BA23 4-Button Control Panel and PC Board (Example).png|300px|thumb|right|BA23 4-Button Control Panel and PC Board (Example)]]

Systems with a 4-button control panel support only full-height mass storage devices.

 

[[File:BA23 6-Button Control Panel and PC Board (Example).png|300px|thumb|right|BA23 6-Button Control Panel and PC Board (Example)]]

Systems with a 6-button control panel support either full-height or half-height devices.

 

==BA23 Signal Distribution Panel==

[[File:BA23 Signal Distribution Panel.png|300px|thumb|left|BA23 Signal Distribution Panel]]

The signal distribution panel carries signals from an [[RQDX1/RQDX2 MFM Disk & Floppy QBUS Controllers|RQDX1]], [[RQDX1/RQDX2 MFM Disk & Floppy QBUS Controllers|RQDX2]], or [[RQDX3 MFM Disk & Floppy QBUS Controller|RQDX3]] controller module in the [[QBUS#Variable_address_size|Q22-bus]] backplane to the mass storage devices.

 

==BA23 H9278 Backplane==

[[File:BA23 Backplane Grant Continuity.png|350px|thumb|right|BA23 H9278 Qbus Backplane Grant Continuity]]

The BA23 enclosure contains the [[QBUS_backplanes#Backplane types|H9278]] Qbus [[backplane]].

The picture shows the H9278 Qbus Backplane [[bus grant]] continuity.

Slots 1-3 are Q/CD; slots 4-8 are Q/Q

 

==BA23 Internal Cabling==

[[File:BA23 Internal Cabling (Example).png|300px|thumb|left|BA23 Internal Cabling (Example)]]

 

==BA23 H7864 Power Supply==

[[File:BA23 Power Supply.png|300px|thumb|right|BA23 H7864 Power Supply]]

There are three variations of the BA23 [[power supply]], depending on the enclosure model number:
H7864, H7864A, or H7864B.

The power supply regulators maintain proper output [[voltage]]s against temporary fluctuations in the ac input to the power supply.

The power supply is a 230 W unit. It supplies +5 Vdc at 4.5 amps (A) to 36.0 A, and +12 Vdc at 0.0 A to 7.0 A to the following system components:

* Backplane
* Fixed-disk drive
* Diskette drive or tape drive

 

The power supply also sends three system control signals to the backplane, asserting two of these signals (BDCOK H and BPOK H) when the system power is stable.
The third signal (BEVENT L) is an external line clock interrupt request to the CPU. The LTC switch on the control panel PC board enables the BEVENT signal.

The power supply also has two +10 Vdc at 0.45 A fan outputs for the front and rear dc fans.
You can increase the fan voltages to +12 Vdc by changing a power supply jumper.
The [[KA630]] CPU module’s thermal and acoustical specifications for example, are based on the +10 volt setting.
The required fan power does not affect the 230 W output.

=== Capacitor Issues ===

The BA23 power supply contains one or more RIFA capacitors, which should be replaced before operation. These capacitors fail due to moisture ingress from cracks in the encapsulation. They release great quantities of smoke when they fail.

The BA23 power supply assembly AA12131, manufactured by Aztec, has been found with leaking general purpose and low ESR capacitors, and should be recapped when disassembled for RIFA replacement. The large capacitors in the fan supply circuit generally do not require replacement, nor do the bulk capacitors immediately after the AC line rectifiers. A capacitor list has been provided in the External Links section.

==BA23 I/O Panel==

[[File:BA23 I-O Panel.png|300px|thumb|right|BA23 I/O Panel Adapter plate with typical type A and B inserts]]

You use the I/O panel to connect external devices to the system.

Each device connects to a module in the system through a filtered connector.

You mount the connector on an insert, then install the insert in a cutout on the I/O panel.

Filtered connectors and inserts are part of the option’s cabinet kit.

Usually, the CPU insert is installed in the top (or left) cutout.

The I/O panel has six cutouts in two sizes, types A and B.

 

{| class="wikitable" style="text-align:center;"
! colspan="5" | BA23 I/O Panel Cutout and Insert Sizes
|-
| Type || Quantity || C/I || Inches || Millimeters
|-
| A || 2 || Cutout || 0.6 x 3.2 || 15 x 81
|-
| A || 2 || Insert || 1.0 x 4.0 || 25 x 102
|-
| B || 4 || Cutout || 2.25 x 3.2 || 57 x 81
|-
| B || 4 || Insert || 2.5 x 3.3 || 64 x 84
|}

You can install three more type A inserts by removing the bracket between the third and fourth cutouts and installing an adapter plate.

==Cooling Considerations==

The BA23 uses an airflow path which pulls cooling air through the card cage, into the [[power supply]], and exhausts it through the top (in vertical orientation) or left (horizontal orientation, from the front) side of the chassis through two 120V 120mm fans. The fan closest to the rear of the chassis is mostly responsible for power supply and [[QBus]] card cage cooling, the fan closest to the front of the chassis handles storage area cooling.

Operating the BA23 with the I/O panel removed may reduce cooling efficiency, leading to hot running or overheating when running programs which stress the system, such as the [[XXDP]] '''VMJAB0''' memory exerciser, especially in configurations that include a [[KDJ11-B]]. The intake side of the chassis should be kept free from obstructions during operation, as the fans in the output side will pull intake air from the path of least resistance.

When operating the BA23 in a rack mounted configuration, ensure adequate intake and exhaust airflow. This often precludes the use of rack side skins.

==External links==

* [http://bitsavers.trailing-edge.com/scandocs.trailing-edge.com/micropdp11-volume_2_enclosures-EK-186AA-MG-001.pdf BA23 Enclosure Maintenance] (EK-186AA-MG-001)
* [http://filedump.glitchwrks.com/cap_lists/dec_ba23_aa12131.pdf DEC BA23 AA12131 Power Supply Capacitor List]

[[Category: DEC Mounting Boxes]]

BA23 Enclosure

2024-07-19T12:28:57Z

Glitch: /* Cooling Considerations */

[[File:BA23 Enclosure Pedestal Version (MicroVAX).png|350px|thumb|right|BA23 Enclosure Pedestal Version (MicroVAX)]]

The '''BA23 Enclosure''' is a [[QBUS]] [[mounting box]] from [[Digital Equipment Corporation|DEC]] which is available in pedestal, table-top, and rack mount versions. There is also a 'bigger brother', the [[BA123]] enclosure.

The BA23 is the successor to the [[BA11-M mounting box|BA11-M]] QBUS mounting box.

The BA23 enclosure is famous for the risk to skin one's knuckles - it is packed inside very tightly.

==BA23 Usage==

The BA23 enclosure was used for the following DEC [[PDP-11]], [[VAXstation]], and [[MicroVAX]] computers:

* [[PDP-11/23+]]
* [[PDP-11/53]]
* [[PDP-11/73]]
* [[PDP-11/83]]
* [[PDP-11/93]]

* [[MicroVAX I]]
* [[VAXstation I]]
* [[MicroVAX II]]
* [[VAXstation II]]
* [[VAXstation 3200/3500 | VAXstation 3200]]

Some versions of the computers listed above were also available in the BA123 enclosure, or in the [[H9642]] Medium System Cabinet.

The H9642 Medium System Cabinet contains two BA23 enclosures, one 'Standard' BA23-A, and one 'Expander' BA23-C.

In the cabinet both BA23 enclosures are connected with a [[BCV2A]] 'Qbus expansion cable and terminator BA23A to BA23C' to provide a large Qbus configuration.

==BA23 Mass Storage Device Areas==

[[File:BA23 Mass Storage Locations.png|300px|thumb|left|BA23 Mass Storage Locations A & B]]

The BA23 can hold full-height and half-height 13.3 cm (5.25 in) mass storage devices, depending on the system.

You can install one [[RD5x-series]] fixed-disk drive and one removable-media drive — an [[RX50]] diskette drive or a [[TK50]] tape drive.
You cannot install two full-height, fixed-disk drives due to power limitations.

You can connect external drives to the system’s I/O distribution panel.

The number of drives you can use depends on the space available in the I/O panel and backplane, and the amount of power available to run the drive controllers.

 

==BA23 Control Panel==

The BA23 has either a 4- or 6-button control panel as follows:

[[File:BA23 4-Button Control Panel and PC Board (Example).png|300px|thumb|right|BA23 4-Button Control Panel and PC Board (Example)]]

Systems with a 4-button control panel support only full-height mass storage devices.

 

[[File:BA23 6-Button Control Panel and PC Board (Example).png|300px|thumb|right|BA23 6-Button Control Panel and PC Board (Example)]]

Systems with a 6-button control panel support either full-height or half-height devices.

 

==BA23 Signal Distribution Panel==

[[File:BA23 Signal Distribution Panel.png|300px|thumb|left|BA23 Signal Distribution Panel]]

The signal distribution panel carries signals from an [[RQDX1/RQDX2 MFM Disk & Floppy QBUS Controllers|RQDX1]], [[RQDX1/RQDX2 MFM Disk & Floppy QBUS Controllers|RQDX2]], or [[RQDX3 MFM Disk & Floppy QBUS Controller|RQDX3]] controller module in the [[QBUS#Variable_address_size|Q22-bus]] backplane to the mass storage devices.

 

==BA23 H9278 Backplane==

[[File:BA23 Backplane Grant Continuity.png|350px|thumb|right|BA23 H9278 Qbus Backplane Grant Continuity]]

The BA23 enclosure contains the [[QBUS_backplanes#Backplane types|H9278]] Qbus [[backplane]].

The picture shows the H9278 Qbus Backplane [[bus grant]] continuity.

Slots 1-3 are Q/CD; slots 4-8 are Q/Q

 

==BA23 Internal Cabling==

[[File:BA23 Internal Cabling (Example).png|300px|thumb|left|BA23 Internal Cabling (Example)]]

 

==BA23 H7864 Power Supply==

[[File:BA23 Power Supply.png|300px|thumb|right|BA23 H7864 Power Supply]]

There are three variations of the BA23 [[power supply]], depending on the enclosure model number:
H7864, H7864A, or H7864B.

The power supply regulators maintain proper output [[voltage]]s against temporary fluctuations in the ac input to the power supply.

The power supply is a 230 W unit. It supplies +5 Vdc at 4.5 amps (A) to 36.0 A, and +12 Vdc at 0.0 A to 7.0 A to the following system components:

* Backplane
* Fixed-disk drive
* Diskette drive or tape drive

 

The power supply also sends three system control signals to the backplane, asserting two of these signals (BDCOK H and BPOK H) when the system power is stable.
The third signal (BEVENT L) is an external line clock interrupt request to the CPU. The LTC switch on the control panel PC board enables the BEVENT signal.

The power supply also has two +10 Vdc at 0.45 A fan outputs for the front and rear dc fans.
You can increase the fan voltages to +12 Vdc by changing a power supply jumper.
The [[KA630]] CPU module’s thermal and acoustical specifications for example, are based on the +10 volt setting.
The required fan power does not affect the 230 W output.

=== Capacitor Issues ===

The BA23 power supply contains one or more RIFA capacitors, which should be replaced before operation. These capacitors fail due to moisture ingress from cracks in the encapsulation. They release great quantities of smoke when they fail.

The BA23 power supply assembly AA12131, manufactured by Aztec, has been found with leaking general purpose and low ESR capacitors, and should be recapped when disassembled for RIFA replacement. The large capacitors in the fan supply circuit generally do not require replacement, nor do the bulk capacitors immediately after the AC line rectifiers. A capacitor list has been provided in the External Links section.

==BA23 I/O Panel==

[[File:BA23 I-O Panel.png|300px|thumb|right|BA23 I/O Panel Adapter plate with typical type A and B inserts]]

You use the I/O panel to connect external devices to the system.

Each device connects to a module in the system through a filtered connector.

You mount the connector on an insert, then install the insert in a cutout on the I/O panel.

Filtered connectors and inserts are part of the option’s cabinet kit.

Usually, the CPU insert is installed in the top (or left) cutout.

The I/O panel has six cutouts in two sizes, types A and B.

 

{| class="wikitable" style="text-align:center;"
! colspan="5" | BA23 I/O Panel Cutout and Insert Sizes
|-
| Type || Quantity || C/I || Inches || Millimeters
|-
| A || 2 || Cutout || 0.6 x 3.2 || 15 x 81
|-
| A || 2 || Insert || 1.0 x 4.0 || 25 x 102
|-
| B || 4 || Cutout || 2.25 x 3.2 || 57 x 81
|-
| B || 4 || Insert || 2.5 x 3.3 || 64 x 84
|}

You can install three more type A inserts by removing the bracket between the third and fourth cutouts and installing an adapter plate.

==Cooling Considerations==

The BA23 uses an airflow path which pulls cooling air through the card cage, into the power supply, and exhausts it through the top (in vertical orientation) or left (horizontal orientation, from the front) side of the chassis through two 120V 120mm fans. The fan closest to the rear of the chassis is mostly responsible for power supply and QBus card cage cooling, the fan closest to the front of the chassis handles storage area cooling.

Operating the BA23 with the I/O panel removed may reduce cooling efficiency, leading to hot running or overheating when running programs which stress the system, such as the XXDP '''VMJAB0''' memory exerciser, especially in configurations that include a KDJ11-B. The intake side of the chassis should be kept free from obstructions during operation, as the fans in the output side will pull intake air from the path of least resistance.

When operating the BA23 in a rack mounted configuration, ensure adequate intake and exhaust airflow. This often precludes the use of rack side skins.

==External links==

* [http://bitsavers.trailing-edge.com/scandocs.trailing-edge.com/micropdp11-volume_2_enclosures-EK-186AA-MG-001.pdf BA23 Enclosure Maintenance] (EK-186AA-MG-001)
* [http://filedump.glitchwrks.com/cap_lists/dec_ba23_aa12131.pdf DEC BA23 AA12131 Power Supply Capacitor List]

[[Category: DEC Mounting Boxes]]

BA23 Enclosure

2024-07-19T12:23:14Z

Glitch: Adding section for BA23 cooling considerations

[[File:BA23 Enclosure Pedestal Version (MicroVAX).png|350px|thumb|right|BA23 Enclosure Pedestal Version (MicroVAX)]]

The '''BA23 Enclosure''' is a [[QBUS]] [[mounting box]] from [[Digital Equipment Corporation|DEC]] which is available in pedestal, table-top, and rack mount versions. There is also a 'bigger brother', the [[BA123]] enclosure.

The BA23 is the successor to the [[BA11-M mounting box|BA11-M]] QBUS mounting box.

The BA23 enclosure is famous for the risk to skin one's knuckles - it is packed inside very tightly.

==BA23 Usage==

The BA23 enclosure was used for the following DEC [[PDP-11]], [[VAXstation]], and [[MicroVAX]] computers:

* [[PDP-11/23+]]
* [[PDP-11/53]]
* [[PDP-11/73]]
* [[PDP-11/83]]
* [[PDP-11/93]]

* [[MicroVAX I]]
* [[VAXstation I]]
* [[MicroVAX II]]
* [[VAXstation II]]
* [[VAXstation 3200/3500 | VAXstation 3200]]

Some versions of the computers listed above were also available in the BA123 enclosure, or in the [[H9642]] Medium System Cabinet.

The H9642 Medium System Cabinet contains two BA23 enclosures, one 'Standard' BA23-A, and one 'Expander' BA23-C.

In the cabinet both BA23 enclosures are connected with a [[BCV2A]] 'Qbus expansion cable and terminator BA23A to BA23C' to provide a large Qbus configuration.

==BA23 Mass Storage Device Areas==

[[File:BA23 Mass Storage Locations.png|300px|thumb|left|BA23 Mass Storage Locations A & B]]

The BA23 can hold full-height and half-height 13.3 cm (5.25 in) mass storage devices, depending on the system.

You can install one [[RD5x-series]] fixed-disk drive and one removable-media drive — an [[RX50]] diskette drive or a [[TK50]] tape drive.
You cannot install two full-height, fixed-disk drives due to power limitations.

You can connect external drives to the system’s I/O distribution panel.

The number of drives you can use depends on the space available in the I/O panel and backplane, and the amount of power available to run the drive controllers.

 

==BA23 Control Panel==

The BA23 has either a 4- or 6-button control panel as follows:

[[File:BA23 4-Button Control Panel and PC Board (Example).png|300px|thumb|right|BA23 4-Button Control Panel and PC Board (Example)]]

Systems with a 4-button control panel support only full-height mass storage devices.

 

[[File:BA23 6-Button Control Panel and PC Board (Example).png|300px|thumb|right|BA23 6-Button Control Panel and PC Board (Example)]]

Systems with a 6-button control panel support either full-height or half-height devices.

 

==BA23 Signal Distribution Panel==

[[File:BA23 Signal Distribution Panel.png|300px|thumb|left|BA23 Signal Distribution Panel]]

The signal distribution panel carries signals from an [[RQDX1/RQDX2 MFM Disk & Floppy QBUS Controllers|RQDX1]], [[RQDX1/RQDX2 MFM Disk & Floppy QBUS Controllers|RQDX2]], or [[RQDX3 MFM Disk & Floppy QBUS Controller|RQDX3]] controller module in the [[QBUS#Variable_address_size|Q22-bus]] backplane to the mass storage devices.

 

==BA23 H9278 Backplane==

[[File:BA23 Backplane Grant Continuity.png|350px|thumb|right|BA23 H9278 Qbus Backplane Grant Continuity]]

The BA23 enclosure contains the [[QBUS_backplanes#Backplane types|H9278]] Qbus [[backplane]].

The picture shows the H9278 Qbus Backplane [[bus grant]] continuity.

Slots 1-3 are Q/CD; slots 4-8 are Q/Q

 

==BA23 Internal Cabling==

[[File:BA23 Internal Cabling (Example).png|300px|thumb|left|BA23 Internal Cabling (Example)]]

 

==BA23 H7864 Power Supply==

[[File:BA23 Power Supply.png|300px|thumb|right|BA23 H7864 Power Supply]]

There are three variations of the BA23 [[power supply]], depending on the enclosure model number:
H7864, H7864A, or H7864B.

The power supply regulators maintain proper output [[voltage]]s against temporary fluctuations in the ac input to the power supply.

The power supply is a 230 W unit. It supplies +5 Vdc at 4.5 amps (A) to 36.0 A, and +12 Vdc at 0.0 A to 7.0 A to the following system components:

* Backplane
* Fixed-disk drive
* Diskette drive or tape drive

 

The power supply also sends three system control signals to the backplane, asserting two of these signals (BDCOK H and BPOK H) when the system power is stable.
The third signal (BEVENT L) is an external line clock interrupt request to the CPU. The LTC switch on the control panel PC board enables the BEVENT signal.

The power supply also has two +10 Vdc at 0.45 A fan outputs for the front and rear dc fans.
You can increase the fan voltages to +12 Vdc by changing a power supply jumper.
The [[KA630]] CPU module’s thermal and acoustical specifications for example, are based on the +10 volt setting.
The required fan power does not affect the 230 W output.

=== Capacitor Issues ===

The BA23 power supply contains one or more RIFA capacitors, which should be replaced before operation. These capacitors fail due to moisture ingress from cracks in the encapsulation. They release great quantities of smoke when they fail.

The BA23 power supply assembly AA12131, manufactured by Aztec, has been found with leaking general purpose and low ESR capacitors, and should be recapped when disassembled for RIFA replacement. The large capacitors in the fan supply circuit generally do not require replacement, nor do the bulk capacitors immediately after the AC line rectifiers. A capacitor list has been provided in the External Links section.

==BA23 I/O Panel==

[[File:BA23 I-O Panel.png|300px|thumb|right|BA23 I/O Panel Adapter plate with typical type A and B inserts]]

You use the I/O panel to connect external devices to the system.

Each device connects to a module in the system through a filtered connector.

You mount the connector on an insert, then install the insert in a cutout on the I/O panel.

Filtered connectors and inserts are part of the option’s cabinet kit.

Usually, the CPU insert is installed in the top (or left) cutout.

The I/O panel has six cutouts in two sizes, types A and B.

 

{| class="wikitable" style="text-align:center;"
! colspan="5" | BA23 I/O Panel Cutout and Insert Sizes
|-
| Type || Quantity || C/I || Inches || Millimeters
|-
| A || 2 || Cutout || 0.6 x 3.2 || 15 x 81
|-
| A || 2 || Insert || 1.0 x 4.0 || 25 x 102
|-
| B || 4 || Cutout || 2.25 x 3.2 || 57 x 81
|-
| B || 4 || Insert || 2.5 x 3.3 || 64 x 84
|}

You can install three more type A inserts by removing the bracket between the third and fourth cutouts and installing an adapter plate.

==Cooling Considerations==

==External links==

* [http://bitsavers.trailing-edge.com/scandocs.trailing-edge.com/micropdp11-volume_2_enclosures-EK-186AA-MG-001.pdf BA23 Enclosure Maintenance] (EK-186AA-MG-001)
* [http://filedump.glitchwrks.com/cap_lists/dec_ba23_aa12131.pdf DEC BA23 AA12131 Power Supply Capacitor List]

[[Category: DEC Mounting Boxes]]

BA23 Enclosure

2024-07-19T12:20:52Z

Glitch: /* BA23 H7864 Power Supply */

[[File:BA23 Enclosure Pedestal Version (MicroVAX).png|350px|thumb|right|BA23 Enclosure Pedestal Version (MicroVAX)]]

The '''BA23 Enclosure''' is a [[QBUS]] [[mounting box]] from [[Digital Equipment Corporation|DEC]] which is available in pedestal, table-top, and rack mount versions. There is also a 'bigger brother', the [[BA123]] enclosure.

The BA23 is the successor to the [[BA11-M mounting box|BA11-M]] QBUS mounting box.

The BA23 enclosure is famous for the risk to skin one's knuckles - it is packed inside very tightly.

==BA23 Usage==

The BA23 enclosure was used for the following DEC [[PDP-11]], [[VAXstation]], and [[MicroVAX]] computers:

* [[PDP-11/23+]]
* [[PDP-11/53]]
* [[PDP-11/73]]
* [[PDP-11/83]]
* [[PDP-11/93]]

* [[MicroVAX I]]
* [[VAXstation I]]
* [[MicroVAX II]]
* [[VAXstation II]]
* [[VAXstation 3200/3500 | VAXstation 3200]]

Some versions of the computers listed above were also available in the BA123 enclosure, or in the [[H9642]] Medium System Cabinet.

The H9642 Medium System Cabinet contains two BA23 enclosures, one 'Standard' BA23-A, and one 'Expander' BA23-C.

In the cabinet both BA23 enclosures are connected with a [[BCV2A]] 'Qbus expansion cable and terminator BA23A to BA23C' to provide a large Qbus configuration.

==BA23 Mass Storage Device Areas==

[[File:BA23 Mass Storage Locations.png|300px|thumb|left|BA23 Mass Storage Locations A & B]]

The BA23 can hold full-height and half-height 13.3 cm (5.25 in) mass storage devices, depending on the system.

You can install one [[RD5x-series]] fixed-disk drive and one removable-media drive — an [[RX50]] diskette drive or a [[TK50]] tape drive.
You cannot install two full-height, fixed-disk drives due to power limitations.

You can connect external drives to the system’s I/O distribution panel.

The number of drives you can use depends on the space available in the I/O panel and backplane, and the amount of power available to run the drive controllers.

 

==BA23 Control Panel==

The BA23 has either a 4- or 6-button control panel as follows:

[[File:BA23 4-Button Control Panel and PC Board (Example).png|300px|thumb|right|BA23 4-Button Control Panel and PC Board (Example)]]

Systems with a 4-button control panel support only full-height mass storage devices.

 

[[File:BA23 6-Button Control Panel and PC Board (Example).png|300px|thumb|right|BA23 6-Button Control Panel and PC Board (Example)]]

Systems with a 6-button control panel support either full-height or half-height devices.

 

==BA23 Signal Distribution Panel==

[[File:BA23 Signal Distribution Panel.png|300px|thumb|left|BA23 Signal Distribution Panel]]

The signal distribution panel carries signals from an [[RQDX1/RQDX2 MFM Disk & Floppy QBUS Controllers|RQDX1]], [[RQDX1/RQDX2 MFM Disk & Floppy QBUS Controllers|RQDX2]], or [[RQDX3 MFM Disk & Floppy QBUS Controller|RQDX3]] controller module in the [[QBUS#Variable_address_size|Q22-bus]] backplane to the mass storage devices.

 

==BA23 H9278 Backplane==

[[File:BA23 Backplane Grant Continuity.png|350px|thumb|right|BA23 H9278 Qbus Backplane Grant Continuity]]

The BA23 enclosure contains the [[QBUS_backplanes#Backplane types|H9278]] Qbus [[backplane]].

The picture shows the H9278 Qbus Backplane [[bus grant]] continuity.

Slots 1-3 are Q/CD; slots 4-8 are Q/Q

 

==BA23 Internal Cabling==

[[File:BA23 Internal Cabling (Example).png|300px|thumb|left|BA23 Internal Cabling (Example)]]

 

==BA23 H7864 Power Supply==

[[File:BA23 Power Supply.png|300px|thumb|right|BA23 H7864 Power Supply]]

There are three variations of the BA23 [[power supply]], depending on the enclosure model number:
H7864, H7864A, or H7864B.

The power supply regulators maintain proper output [[voltage]]s against temporary fluctuations in the ac input to the power supply.

The power supply is a 230 W unit. It supplies +5 Vdc at 4.5 amps (A) to 36.0 A, and +12 Vdc at 0.0 A to 7.0 A to the following system components:

* Backplane
* Fixed-disk drive
* Diskette drive or tape drive

 

The power supply also sends three system control signals to the backplane, asserting two of these signals (BDCOK H and BPOK H) when the system power is stable.
The third signal (BEVENT L) is an external line clock interrupt request to the CPU. The LTC switch on the control panel PC board enables the BEVENT signal.

The power supply also has two +10 Vdc at 0.45 A fan outputs for the front and rear dc fans.
You can increase the fan voltages to +12 Vdc by changing a power supply jumper.
The [[KA630]] CPU module’s thermal and acoustical specifications for example, are based on the +10 volt setting.
The required fan power does not affect the 230 W output.

=== Capacitor Issues ===

The BA23 power supply contains one or more RIFA capacitors, which should be replaced before operation. These capacitors fail due to moisture ingress from cracks in the encapsulation. They release great quantities of smoke when they fail.

The BA23 power supply assembly AA12131, manufactured by Aztec, has been found with leaking general purpose and low ESR capacitors, and should be recapped when disassembled for RIFA replacement. The large capacitors in the fan supply circuit generally do not require replacement, nor do the bulk capacitors immediately after the AC line rectifiers. A capacitor list has been provided in the External Links section.

==BA23 I/O Panel==

[[File:BA23 I-O Panel.png|300px|thumb|right|BA23 I/O Panel Adapter plate with typical type A and B inserts]]

You use the I/O panel to connect external devices to the system.

Each device connects to a module in the system through a filtered connector.

You mount the connector on an insert, then install the insert in a cutout on the I/O panel.

Filtered connectors and inserts are part of the option’s cabinet kit.

Usually, the CPU insert is installed in the top (or left) cutout.

The I/O panel has six cutouts in two sizes, types A and B.

 

{| class="wikitable" style="text-align:center;"
! colspan="5" | BA23 I/O Panel Cutout and Insert Sizes
|-
| Type || Quantity || C/I || Inches || Millimeters
|-
| A || 2 || Cutout || 0.6 x 3.2 || 15 x 81
|-
| A || 2 || Insert || 1.0 x 4.0 || 25 x 102
|-
| B || 4 || Cutout || 2.25 x 3.2 || 57 x 81
|-
| B || 4 || Insert || 2.5 x 3.3 || 64 x 84
|}

You can install three more type A inserts by removing the bracket between the third and fourth cutouts and installing an adapter plate.

==External links==

* [http://bitsavers.trailing-edge.com/scandocs.trailing-edge.com/micropdp11-volume_2_enclosures-EK-186AA-MG-001.pdf BA23 Enclosure Maintenance] (EK-186AA-MG-001)
* [http://filedump.glitchwrks.com/cap_lists/dec_ba23_aa12131.pdf DEC BA23 AA12131 Power Supply Capacitor List]

[[Category: DEC Mounting Boxes]]

BA23 Enclosure

2024-07-19T12:16:26Z

Glitch: /* External links */

[[File:BA23 Enclosure Pedestal Version (MicroVAX).png|350px|thumb|right|BA23 Enclosure Pedestal Version (MicroVAX)]]

The '''BA23 Enclosure''' is a [[QBUS]] [[mounting box]] from [[Digital Equipment Corporation|DEC]] which is available in pedestal, table-top, and rack mount versions. There is also a 'bigger brother', the [[BA123]] enclosure.

The BA23 is the successor to the [[BA11-M mounting box|BA11-M]] QBUS mounting box.

The BA23 enclosure is famous for the risk to skin one's knuckles - it is packed inside very tightly.

==BA23 Usage==

The BA23 enclosure was used for the following DEC [[PDP-11]], [[VAXstation]], and [[MicroVAX]] computers:

* [[PDP-11/23+]]
* [[PDP-11/53]]
* [[PDP-11/73]]
* [[PDP-11/83]]
* [[PDP-11/93]]

* [[MicroVAX I]]
* [[VAXstation I]]
* [[MicroVAX II]]
* [[VAXstation II]]
* [[VAXstation 3200/3500 | VAXstation 3200]]

Some versions of the computers listed above were also available in the BA123 enclosure, or in the [[H9642]] Medium System Cabinet.

The H9642 Medium System Cabinet contains two BA23 enclosures, one 'Standard' BA23-A, and one 'Expander' BA23-C.

In the cabinet both BA23 enclosures are connected with a [[BCV2A]] 'Qbus expansion cable and terminator BA23A to BA23C' to provide a large Qbus configuration.

==BA23 Mass Storage Device Areas==

[[File:BA23 Mass Storage Locations.png|300px|thumb|left|BA23 Mass Storage Locations A & B]]

The BA23 can hold full-height and half-height 13.3 cm (5.25 in) mass storage devices, depending on the system.

You can install one [[RD5x-series]] fixed-disk drive and one removable-media drive — an [[RX50]] diskette drive or a [[TK50]] tape drive.
You cannot install two full-height, fixed-disk drives due to power limitations.

You can connect external drives to the system’s I/O distribution panel.

The number of drives you can use depends on the space available in the I/O panel and backplane, and the amount of power available to run the drive controllers.

 

==BA23 Control Panel==

The BA23 has either a 4- or 6-button control panel as follows:

[[File:BA23 4-Button Control Panel and PC Board (Example).png|300px|thumb|right|BA23 4-Button Control Panel and PC Board (Example)]]

Systems with a 4-button control panel support only full-height mass storage devices.

 

[[File:BA23 6-Button Control Panel and PC Board (Example).png|300px|thumb|right|BA23 6-Button Control Panel and PC Board (Example)]]

Systems with a 6-button control panel support either full-height or half-height devices.

 

==BA23 Signal Distribution Panel==

[[File:BA23 Signal Distribution Panel.png|300px|thumb|left|BA23 Signal Distribution Panel]]

The signal distribution panel carries signals from an [[RQDX1/RQDX2 MFM Disk & Floppy QBUS Controllers|RQDX1]], [[RQDX1/RQDX2 MFM Disk & Floppy QBUS Controllers|RQDX2]], or [[RQDX3 MFM Disk & Floppy QBUS Controller|RQDX3]] controller module in the [[QBUS#Variable_address_size|Q22-bus]] backplane to the mass storage devices.

 

==BA23 H9278 Backplane==

[[File:BA23 Backplane Grant Continuity.png|350px|thumb|right|BA23 H9278 Qbus Backplane Grant Continuity]]

The BA23 enclosure contains the [[QBUS_backplanes#Backplane types|H9278]] Qbus [[backplane]].

The picture shows the H9278 Qbus Backplane [[bus grant]] continuity.

Slots 1-3 are Q/CD; slots 4-8 are Q/Q

 

==BA23 Internal Cabling==

[[File:BA23 Internal Cabling (Example).png|300px|thumb|left|BA23 Internal Cabling (Example)]]

 

==BA23 H7864 Power Supply==

[[File:BA23 Power Supply.png|300px|thumb|right|BA23 H7864 Power Supply]]

There are three variations of the BA23 [[power supply]], depending on the enclosure model number:
H7864, H7864A, or H7864B.

The power supply regulators maintain proper output [[voltage]]s against temporary fluctuations in the ac input to the power supply.

The power supply is a 230 W unit. It supplies +5 Vdc at 4.5 amps (A) to 36.0 A, and +12 Vdc at 0.0 A to 7.0 A to the following system components:

* Backplane
* Fixed-disk drive
* Diskette drive or tape drive

 

The power supply also sends three system control signals to the backplane, asserting two of these signals (BDCOK H and BPOK H) when the system power is stable.
The third signal (BEVENT L) is an external line clock interrupt request to the CPU. The LTC switch on the control panel PC board enables the BEVENT signal.

The power supply also has two +10 Vdc at 0.45 A fan outputs for the front and rear dc fans.
You can increase the fan voltages to +12 Vdc by changing a power supply jumper.
The [[KA630]] CPU module’s thermal and acoustical specifications for example, are based on the +10 volt setting.
The required fan power does not affect the 230 W output.

==BA23 I/O Panel==

[[File:BA23 I-O Panel.png|300px|thumb|right|BA23 I/O Panel Adapter plate with typical type A and B inserts]]

You use the I/O panel to connect external devices to the system.

Each device connects to a module in the system through a filtered connector.

You mount the connector on an insert, then install the insert in a cutout on the I/O panel.

Filtered connectors and inserts are part of the option’s cabinet kit.

Usually, the CPU insert is installed in the top (or left) cutout.

The I/O panel has six cutouts in two sizes, types A and B.

 

{| class="wikitable" style="text-align:center;"
! colspan="5" | BA23 I/O Panel Cutout and Insert Sizes
|-
| Type || Quantity || C/I || Inches || Millimeters
|-
| A || 2 || Cutout || 0.6 x 3.2 || 15 x 81
|-
| A || 2 || Insert || 1.0 x 4.0 || 25 x 102
|-
| B || 4 || Cutout || 2.25 x 3.2 || 57 x 81
|-
| B || 4 || Insert || 2.5 x 3.3 || 64 x 84
|}

You can install three more type A inserts by removing the bracket between the third and fourth cutouts and installing an adapter plate.

==External links==

* [http://bitsavers.trailing-edge.com/scandocs.trailing-edge.com/micropdp11-volume_2_enclosures-EK-186AA-MG-001.pdf BA23 Enclosure Maintenance] (EK-186AA-MG-001)
* [http://filedump.glitchwrks.com/cap_lists/dec_ba23_aa12131.pdf DEC BA23 AA12131 Power Supply Capacitor List]

[[Category: DEC Mounting Boxes]]

BA23 Enclosure

2024-07-19T12:15:33Z

Glitch: /* External links */

[[File:BA23 Enclosure Pedestal Version (MicroVAX).png|350px|thumb|right|BA23 Enclosure Pedestal Version (MicroVAX)]]

The '''BA23 Enclosure''' is a [[QBUS]] [[mounting box]] from [[Digital Equipment Corporation|DEC]] which is available in pedestal, table-top, and rack mount versions. There is also a 'bigger brother', the [[BA123]] enclosure.

The BA23 is the successor to the [[BA11-M mounting box|BA11-M]] QBUS mounting box.

The BA23 enclosure is famous for the risk to skin one's knuckles - it is packed inside very tightly.

==BA23 Usage==

The BA23 enclosure was used for the following DEC [[PDP-11]], [[VAXstation]], and [[MicroVAX]] computers:

* [[PDP-11/23+]]
* [[PDP-11/53]]
* [[PDP-11/73]]
* [[PDP-11/83]]
* [[PDP-11/93]]

* [[MicroVAX I]]
* [[VAXstation I]]
* [[MicroVAX II]]
* [[VAXstation II]]
* [[VAXstation 3200/3500 | VAXstation 3200]]

Some versions of the computers listed above were also available in the BA123 enclosure, or in the [[H9642]] Medium System Cabinet.

The H9642 Medium System Cabinet contains two BA23 enclosures, one 'Standard' BA23-A, and one 'Expander' BA23-C.

In the cabinet both BA23 enclosures are connected with a [[BCV2A]] 'Qbus expansion cable and terminator BA23A to BA23C' to provide a large Qbus configuration.

==BA23 Mass Storage Device Areas==

[[File:BA23 Mass Storage Locations.png|300px|thumb|left|BA23 Mass Storage Locations A & B]]

The BA23 can hold full-height and half-height 13.3 cm (5.25 in) mass storage devices, depending on the system.

You can install one [[RD5x-series]] fixed-disk drive and one removable-media drive — an [[RX50]] diskette drive or a [[TK50]] tape drive.
You cannot install two full-height, fixed-disk drives due to power limitations.

You can connect external drives to the system’s I/O distribution panel.

The number of drives you can use depends on the space available in the I/O panel and backplane, and the amount of power available to run the drive controllers.

 

==BA23 Control Panel==

The BA23 has either a 4- or 6-button control panel as follows:

[[File:BA23 4-Button Control Panel and PC Board (Example).png|300px|thumb|right|BA23 4-Button Control Panel and PC Board (Example)]]

Systems with a 4-button control panel support only full-height mass storage devices.

 

[[File:BA23 6-Button Control Panel and PC Board (Example).png|300px|thumb|right|BA23 6-Button Control Panel and PC Board (Example)]]

Systems with a 6-button control panel support either full-height or half-height devices.

 

==BA23 Signal Distribution Panel==

[[File:BA23 Signal Distribution Panel.png|300px|thumb|left|BA23 Signal Distribution Panel]]

The signal distribution panel carries signals from an [[RQDX1/RQDX2 MFM Disk & Floppy QBUS Controllers|RQDX1]], [[RQDX1/RQDX2 MFM Disk & Floppy QBUS Controllers|RQDX2]], or [[RQDX3 MFM Disk & Floppy QBUS Controller|RQDX3]] controller module in the [[QBUS#Variable_address_size|Q22-bus]] backplane to the mass storage devices.

 

==BA23 H9278 Backplane==

[[File:BA23 Backplane Grant Continuity.png|350px|thumb|right|BA23 H9278 Qbus Backplane Grant Continuity]]

The BA23 enclosure contains the [[QBUS_backplanes#Backplane types|H9278]] Qbus [[backplane]].

The picture shows the H9278 Qbus Backplane [[bus grant]] continuity.

Slots 1-3 are Q/CD; slots 4-8 are Q/Q

 

==BA23 Internal Cabling==

[[File:BA23 Internal Cabling (Example).png|300px|thumb|left|BA23 Internal Cabling (Example)]]

 

==BA23 H7864 Power Supply==

[[File:BA23 Power Supply.png|300px|thumb|right|BA23 H7864 Power Supply]]

There are three variations of the BA23 [[power supply]], depending on the enclosure model number:
H7864, H7864A, or H7864B.

The power supply regulators maintain proper output [[voltage]]s against temporary fluctuations in the ac input to the power supply.

The power supply is a 230 W unit. It supplies +5 Vdc at 4.5 amps (A) to 36.0 A, and +12 Vdc at 0.0 A to 7.0 A to the following system components:

* Backplane
* Fixed-disk drive
* Diskette drive or tape drive

 

The power supply also sends three system control signals to the backplane, asserting two of these signals (BDCOK H and BPOK H) when the system power is stable.
The third signal (BEVENT L) is an external line clock interrupt request to the CPU. The LTC switch on the control panel PC board enables the BEVENT signal.

The power supply also has two +10 Vdc at 0.45 A fan outputs for the front and rear dc fans.
You can increase the fan voltages to +12 Vdc by changing a power supply jumper.
The [[KA630]] CPU module’s thermal and acoustical specifications for example, are based on the +10 volt setting.
The required fan power does not affect the 230 W output.

==BA23 I/O Panel==

[[File:BA23 I-O Panel.png|300px|thumb|right|BA23 I/O Panel Adapter plate with typical type A and B inserts]]

You use the I/O panel to connect external devices to the system.

Each device connects to a module in the system through a filtered connector.

You mount the connector on an insert, then install the insert in a cutout on the I/O panel.

Filtered connectors and inserts are part of the option’s cabinet kit.

Usually, the CPU insert is installed in the top (or left) cutout.

The I/O panel has six cutouts in two sizes, types A and B.

 

{| class="wikitable" style="text-align:center;"
! colspan="5" | BA23 I/O Panel Cutout and Insert Sizes
|-
| Type || Quantity || C/I || Inches || Millimeters
|-
| A || 2 || Cutout || 0.6 x 3.2 || 15 x 81
|-
| A || 2 || Insert || 1.0 x 4.0 || 25 x 102
|-
| B || 4 || Cutout || 2.25 x 3.2 || 57 x 81
|-
| B || 4 || Insert || 2.5 x 3.3 || 64 x 84
|}

You can install three more type A inserts by removing the bracket between the third and fourth cutouts and installing an adapter plate.

==External links==

* [http://bitsavers.trailing-edge.com/scandocs.trailing-edge.com/micropdp11-volume_2_enclosures-EK-186AA-MG-001.pdf BA23 Enclosure Maintenance] (EK-186AA-MG-001)
* [http://filedump.glitchwrks.com/cap_lists/dec_ba23_aa12131.pdf] (DEC BA23 AA12131 Power Supply Capacitor List)

[[Category: DEC Mounting Boxes]]

QBUS backplanes

2024-07-12T19:08:58Z

Glitch: /* Backplane types */

'''QBUS backplanes''' come mainly in two physical types, [[DEC card form factor|dual-width]] and quad-width. In the quad-width [[backplane]]s, each slot held four 'connectors', DEC's term for a [[DEC edge connector contact identification|group of edge connector pins]], denominated 'A'-'D'.

The [[QBUS]] itself is fully carried in a dual slot, and the quads are further sub-divided into two types, the so-called '''Q/Q''' and '''Q/CD'''. In quad Q/Q units, both sides of each quad slot are fully wired for QBUS, and so a single slot can hold two separate dual-width QBUS [[peripheral controller|devices]]. The device locations are usually arranged for grant priority in so-called 'serpentine' order, i.e. one with the devices in the following kind of order (facing the backplane from the board side):

1-2 4-3 5-6 8-7 9-10

etc (as shown [[:File:BA23 Backplane Grant Continuity.png|here]]).

In a quad Q/CD backplane, the [[DEC edge connector contact identification|CD connectors]] form a private bus, sometimes called the [[CD interconnect]], used to connect together board pairs. (The CD connectors run down the right-hand side, when facing the side of the backplane where the boards plug in, with the CPU at the top.)

It is usually possible to upgrade 18-bit backplanes to 22-bit; see [[Upgrading QBUS backplanes]].

'''''NOTE WELL:''''' For reasons which seem utterly incomprehensible, many boards designed for Q/CD slots (such as [[Private Memory Interconnect|PMI]] cards) '''do not''' avoid the QBUS pins on the CD connectors which contain 'hazardous' (to TTL circuitry) voltages. [''NOTE:'' The exact failure mode here is still not understood; the PMI spec was examined, but no clash of pin assignments was found. The warning is accurate, though: [http://web.frainresearch.org:8080/projects/pdp-11/micronotes/micronote28.txt MicroNote 28] says "MSV11-J MODULES CAN[NOT] BE PLACED IN A Q/Q BACKPLANE SLOT. IF THIS IS ATTEMPTED PERMANENT DAMAGE WILL BE DONE TO THE BOARDS".] So, plugging such a card into a Q/Q backplane will generally '''''destroy''''' the card.

==Backplane types==

The following table lists the backplanes produced by [[Digital Equipment Corporation|DEC]]:

{| class="wikitable"
! ID !! Type !! Height || Address Width !! Chassis !! Termination || Comments
|-
| [[H9270 backplane|H9270-A]] || Q/Q || 4 || Q18 || [[BA11-M mounting box|BA11-M]] || none
|-
| [[H9270 backplane|H9270-Q]] || Q/Q || 4 || Q18/Q22 ||  || none
|-
| [[H9273 backplane|H9273]] || Q/CD || 9 || Q18 || [[BA11-N mounting box|BA11-N]] || none
|-
| H9275 || Q/Q || 9 || Q22 ||  || 120 ohms
|-
| [[H9276 backplane|H9276]] || Q/CD || 9 || Q22 || [[BA11-S mounting box|BA11-S]] || none
|-
| [[H9278 backplane|H9278]] || mixed || 8 || Q22 || [[BA23]] || none || slots 1-3 are Q/CD; slots 4-8 are Q/Q; removable termination packs
|-
| [[54-17507 backplane|54-17507]] || mixed || 12+1 || Q22 || [[BA123]] || 120 ohms || slots 1-4 are Q/CD; slots 5-12 are Q/Q; slot 13 provides only power and the [[DCOK Signal]]
|-
| H9281-Q || Q || 4/8/12 || Q18/Q22 ||   || none/120 ohms
|-
| DDV11-B || hex Q/Q || 9 || Q18 || H909-C || none || E-F connectors un-wired
|-
| DDV11-C || hex Q/Q || 4 || Q18 ||   || none || E-F connectors wired as CD interconnect
|}

'Type' indicates whether it is dual-width ('Q') or quad. 'Height' is the number of slots; the number of dual-width board which can be plugged in is twice this, for Q/Q quad backplanes.

The DDV11-C details are somewhat speculative; in the [[VS11 Graphic System|VS11]], it is used with a [[VSV11 Graphic System|VSV11]], and the VSV11's Video Bus is carried over the E-F connectors. Puzzlingly, the VS11 documentation shows that a DDV11-D may also be used - but it claims to have the E-F connectors un-wired.

==External links==

* [http://www.bitsavers.org/pdf/dec/qbus/Digital_Microcomputer_Products_Handbook_1985.pdf Microcomputer Products Handbook (19850] - backplanes are covered in Part X, 'Backplanes, Enclosures, and Expansion Cables'
* [http://web.frainresearch.org:8080/projects/pdp-11/micronotes/micronote29.txt Q-bus Expansion Concepts] (uNote #029)
* [http://www.douglaspcb.com/ Douglas Electronics] still sells extender cards for DEC backplanes
** [https://www.douglaspcb.com/index.php/6-de-11.html 6-DE-11-C dual extender]
** [https://www.douglaspcb.com/index.php/6-de-8.html 6-DE-8-C quad extender]

[[Category: QBUS Backplanes]]

User:Glitch

2024-07-12T19:06:22Z

Glitch: Created page with "Hi there! This is Jonathan Chapman from Glitch Works, LLC, commonly known as "glitch" or "systems_glitch" online. My personal projects are documented here, there's also a con..."

Hi there! This is Jonathan Chapman from Glitch Works, LLC, commonly known as "glitch" or "systems_glitch" online.

My personal projects are documented here, there's also a contact form if you need to email me:

http://users.glitchwrks.com/~glitch/

...and DEC projects in specific here:

http://users.glitchwrks.com/~glitch/dec