Difference between revisions of "MicroVAX I"

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The '''MicroVAX I''' was basically a [[VAXstation I]] without graphics.
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The [[Digital Equipment Corporation|DEC]] '''MicroVAX I''' was the first of a lot of [[MicroVAX]] models.
 +
It was said to be the slowest [[VAX]] ever (about 0.25 [[VUPS]]) , even slower than the [[VAX-11/730]] resp. [[VAX-11/725]].
 +
 
 +
With a [[VCB01]] Monochrome Video Subsystem added, the MicroVAX I becomes a '''VAXstation I'''.
 +
 
 +
==MicroVAX I CPU==
 +
The '''KD32''' MicroVAX I CPU consists of two quad height [[Qbus]] cards:
 +
 
 +
[[File:M7135_DATAPATH.JPG|400px|thumb|left|M7135 MicroVAX I Data Path Module (DAP)]]
 +
 
 +
* Data Path Module (DAP) M7135
 +
 
 +
<br clear=all>
 +
 
 +
[[File:M7136_MCT.JPG|400px|thumb|left|M7136 MicroVAX I Memory Controller Module (MCT)]]
 +
 
 +
* Memory Controller Module (MCT) M7136
 +
 
 +
<br clear=all>
 +
 
 +
The two CPU modules of the MicroVAX I communicate over the [[CD interconnect]] of the [[QBUS backplanes#Backplane types|H9278 backplane]] interconnect and an over-the-top ribbon cable.
 +
 
 +
The KD32 CPU contains:
 +
* An interface to the Q22 bus which supports block mode transfers and up to four megabytes of physical memory
 +
* An 8 KB direct-mapped cache
 +
* A 512 entry (longword) translation buffer
 +
* A 10 ms nonprogrammable interval timer
 +
* An interface to a console serial line unit (available Baud Rates: 300, 1200, 9600, 19200)
 +
* An 8 KB or 16 KB boot EPROM
 +
* Interfaces to the front control panel and rear patch panel assembly
 +
 
 +
==MicroVAX I Boot ROM==
 +
 
 +
===Boot ROM Restrictions===
 +
 
 +
The MicroVAX I bootstrap [[ROM]] can only bootstrap a system disk attached to the first Mass Storage Control Protocol (MSCP) controller.
 +
 
 +
See the instructions from:
 +
[https://www.it-bcsb.de/download/MicroVMS%20Installation%20and%20Operation%20Guide%20-%20AA-KM46A-TN.pdf AA-KM46A-TN MicroVMS 4.6 Installation and Operations], Chapter C.1 Creating a Console Diskette:
 +
 
 +
The console diskette will contain files used to bootstrap from a disk attached to the
 +
second MSCP controller. Use the following steps to create a console diskette. This
 +
example assumes that the first RC25 disk attached to the second MSCP controller
 +
(DABO) will be the new system disk:
 +
 
 +
# Log in to the system manager's account, '''SYSTEM'''.
 +
# Check the first diskette drive to ensure that it is empty and inactive; the red diskette activity light should not be glowing. If there is a diskette in the drive, remove it following the instructions in Section 3.1.11.
 +
# Label a scratch diskette '''CONSOLE DISKETTE'''. A scratch diskette is a new diskette or a diskette containing no information that you want to save.
 +
# Enter the following command to invoke the command procedure that creates a console diskette for a MicroVAX I system: <br>
 +
: <PRE>$ @SYS$UPDATE:VMBUVAX1
 +
: What system disk do you want to be able to boot from? DABO</PRE>
 +
: Ignore the informational messages displayed on your terminal screen. The procedure prompts you for the name of the diskette drive on which the intermediate media (console diskette) will be mounted. In this example, the media is mounted in diskette drive 1 (DUA1).
 +
: <PRE>Where will the intermediate RX50 media be mounted? DUA1</PRE>
 +
: Insert the diskette labeled '''CONSOLE DISKETTE''' into drive 1 and enter '''YES''' in response to the following prompt:
 +
: <PRE>Are you ready? YES</PRE>
 +
: When it has finished building the console diskette, the system displays the following message: <br>
 +
: <PRE>The media on DUA1 may now be used to boot device DABO</PRE>
 +
After you create the console diskette, write-protect it to prevent anyone from accidentally overwriting the contents. To write-protect a diskette, cover the square notch in the upper-right comer of the diskette with a silver tab. Note that in order to bootstrap the system, the console diskette must be in diskette drive 1.
 +
 
 +
You may want to add the following command to the end of '''SYS$MANAGER:SYSTARTUP.COM''' to mount the console diskette automatically every time you bootstrap the system. This prevents other users from removing the diskette thinking that the drive is not in use.
 +
 
 +
<PRE>$ MOUNT/SYSTEM/FOREIGN $FLOPPY1 INTERMEDIATE</PRE>
 +
 
 +
===Supported Boot Devices===
 +
* All [[RQDX]] devices
 +
* [[MRV11-D]]
 +
* [[DEQNA]]/[[DELQA]]
 +
 
 +
===Boot ROM Characteristics===
 +
* Microverify is the name given to the diagnostics executed by the MicroVAX I boot ROM. There are three LEDs on the DAP module and a seven segment display on the patch panel which will isolate the problem (if any) to one of the two CPU modules.
 +
* Floating Point Instructions in Microcode
 +
* No TOY Clock
 +
 
 +
==MicroVAX I Options==
 +
 
 +
There are a lot of MicroVAX I Options; some of them are not "officially supported", but working nevertheless.
 +
 
 +
===MicroVAX I Memory Options===
 +
 
 +
The  MicroVAX I uses standard Q-bus memories which are not as fast but are also less expensive and usable by both the MicroVAX I and other 16-bit processors (such as the MicroPDP-11).
 +
There are 22 address lines on the Q-bus, limiting maximum memory to 4 MB.
 +
 
 +
* [[MSV11-P]] Parity Memory
 +
* [[MSV11-J]] PMI ECC Memory: not supported, but working!
 +
* [[MSV11-Q]] Parity Memory
 +
* [[MSV11-M]] Parity Memory
 +
 
 +
===MicroVAX I Mass Storage Options===
 +
 
 +
* [[RQDX1]]
 +
* [[RQDX2]]
 +
* [[RQDX3]]
 +
* [[RX50]]
 +
* [[RD51]]
 +
* [[RD52]]
 +
* [[RD53]]
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* [[RD54]]
 +
* [[RD31]]
 +
* [[RD32]]
 +
* [[RQC25]] RC25 Disk System with Qbus Controller, made of:
 +
** [[M7740]]
 +
** [[RC25]]
 +
 
 +
===MicroVAX I Communication Options===
 +
 
 +
* [[DLVJ1]]
 +
* [[DZV11]]
 +
* [[DHV11]]
 +
* [[DZQ11]] not supported, but working!
 +
* [[]]
 +
* [[DEQNA]]
 +
* [[DELQA]]
 +
 
 +
===MicroVAX I Video Options===
 +
 
 +
* [[VCB01]] Monochrome Video Subsystem
 +
 
 +
==MicroVAX I Configuration==
 +
 
 +
==MicroVAX I Diagnostics==
 +
 
 +
MicroVAX I is the only MicroVAX model with "old-style" '''[[VDS]]''' (Vax Diagnostic Supervisor) diagnostics.
 +
 
 +
<PRE>
 +
ATTACH ...
 +
</PRE>
 +
 
  
 
== References ==
 
== References ==
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  <div id="ref_2">[2] Systems & Options Catalog. European Edition. Spring 1990. </div>
 
  <div id="ref_2">[2] Systems & Options Catalog. European Edition. Spring 1990. </div>
  
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{{stub}}
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[[Category: DEC Hardware]]
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{{Nav VAX}}
 
{{Nav VAX}}

Revision as of 08:54, 14 June 2022


MicroVAX I
Summary
Announcement date: October 1983
FRS date: late 1984
Codename: Seahorse
OS support (VMS): MicroVMS V1.0 to VMS V5.0-2
OS support (ULTRIX): ULTRIX/VAX V1.0 to ULTRIX/VAX V2.4?
CPU Details
CPU module: KD32-AA
Number of processors: 1
Translation-buffer: 512 entries [1]
Cache: 8KB
Compatibility mode: No
Console processor: CPU
Console device: None
Memory
Minimum memory: 512KB
Maximum memory: 4MB
I/O
Q-bus: 1 @ 3.3MB/s
LAN support: optional


The DEC MicroVAX I was the first of a lot of MicroVAX models. It was said to be the slowest VAX ever (about 0.25 VUPS) , even slower than the VAX-11/730 resp. VAX-11/725.

With a VCB01 Monochrome Video Subsystem added, the MicroVAX I becomes a VAXstation I.

MicroVAX I CPU

The KD32 MicroVAX I CPU consists of two quad height Qbus cards:

M7135 MicroVAX I Data Path Module (DAP)
  • Data Path Module (DAP) M7135


M7136 MicroVAX I Memory Controller Module (MCT)
  • Memory Controller Module (MCT) M7136


The two CPU modules of the MicroVAX I communicate over the CD interconnect of the H9278 backplane interconnect and an over-the-top ribbon cable.

The KD32 CPU contains:

  • An interface to the Q22 bus which supports block mode transfers and up to four megabytes of physical memory
  • An 8 KB direct-mapped cache
  • A 512 entry (longword) translation buffer
  • A 10 ms nonprogrammable interval timer
  • An interface to a console serial line unit (available Baud Rates: 300, 1200, 9600, 19200)
  • An 8 KB or 16 KB boot EPROM
  • Interfaces to the front control panel and rear patch panel assembly

MicroVAX I Boot ROM

Boot ROM Restrictions

The MicroVAX I bootstrap ROM can only bootstrap a system disk attached to the first Mass Storage Control Protocol (MSCP) controller.

See the instructions from: AA-KM46A-TN MicroVMS 4.6 Installation and Operations, Chapter C.1 Creating a Console Diskette:

The console diskette will contain files used to bootstrap from a disk attached to the second MSCP controller. Use the following steps to create a console diskette. This example assumes that the first RC25 disk attached to the second MSCP controller (DABO) will be the new system disk:

  1. Log in to the system manager's account, SYSTEM.
  2. Check the first diskette drive to ensure that it is empty and inactive; the red diskette activity light should not be glowing. If there is a diskette in the drive, remove it following the instructions in Section 3.1.11.
  3. Label a scratch diskette CONSOLE DISKETTE. A scratch diskette is a new diskette or a diskette containing no information that you want to save.
  4. Enter the following command to invoke the command procedure that creates a console diskette for a MicroVAX I system: 
$ @SYS$UPDATE:VMBUVAX1
What system disk do you want to be able to boot from? DABO
Ignore the informational messages displayed on your terminal screen. The procedure prompts you for the name of the diskette drive on which the intermediate media (console diskette) will be mounted. In this example, the media is mounted in diskette drive 1 (DUA1).
Where will the intermediate RX50 media be mounted? DUA1
Insert the diskette labeled CONSOLE DISKETTE into drive 1 and enter YES in response to the following prompt:
Are you ready? YES
When it has finished building the console diskette, the system displays the following message: 
The media on DUA1 may now be used to boot device DABO

After you create the console diskette, write-protect it to prevent anyone from accidentally overwriting the contents. To write-protect a diskette, cover the square notch in the upper-right comer of the diskette with a silver tab. Note that in order to bootstrap the system, the console diskette must be in diskette drive 1.

You may want to add the following command to the end of SYS$MANAGER:SYSTARTUP.COM to mount the console diskette automatically every time you bootstrap the system. This prevents other users from removing the diskette thinking that the drive is not in use. 

$ MOUNT/SYSTEM/FOREIGN $FLOPPY1 INTERMEDIATE

Supported Boot Devices

Boot ROM Characteristics

  • Microverify is the name given to the diagnostics executed by the MicroVAX I boot ROM. There are three LEDs on the DAP module and a seven segment display on the patch panel which will isolate the problem (if any) to one of the two CPU modules.
  • Floating Point Instructions in Microcode
  • No TOY Clock

MicroVAX I Options

There are a lot of MicroVAX I Options; some of them are not "officially supported", but working nevertheless.

MicroVAX I Memory Options

The MicroVAX I uses standard Q-bus memories which are not as fast but are also less expensive and usable by both the MicroVAX I and other 16-bit processors (such as the MicroPDP-11). There are 22 address lines on the Q-bus, limiting maximum memory to 4 MB.

MicroVAX I Mass Storage Options

MicroVAX I Communication Options

MicroVAX I Video Options

  • VCB01 Monochrome Video Subsystem

MicroVAX I Configuration

MicroVAX I Diagnostics

MicroVAX I is the only MicroVAX model with "old-style" VDS (Vax Diagnostic Supervisor) diagnostics. 

ATTACH ...


References

[1] MicroVAX Handbook. EB-25156-47
[2] Systems & Options Catalog. European Edition. Spring 1990.


v • d • e VAX Computers and Operating Systems
VAX-11/7xx (including VAX 86x0) - VAX-11/780 • VAX-11/785 • VAX-11/750 • VAX-11/730 • VAX 8600 • VAX 8650

VAX 8000 series (excluding VAX 86x0) - VAX 82xx/83xx series • VAX 85x0/8700/88xx series

MicroVAXen (many types also come in VAXserver and VAXstation models) - MicroVAX I • MicroVAX II
MicroVAX 2000 • MicroVAX 3100 • MicroVAX 3300/3400 • MicroVAX 3500/3600 • MicroVAX 3800/3900

VAXstation Series - VAXstation I • VAXstation II
VAXstation 3100 • VAXstation 3200/3500 • VAXstation 3520/3540 • VAXstation 8000

Late Model VAXen - VAX 4000 series • VAX 6000 series • VAX 7000 series • VAX 9000 series • VAX 10000 series

Special Purpose VAXen - VAXft series • rtVAX series • Infoserver series

Clones - CM 1700 • TPA-11/580

Operating Systems: VMS • VAXELN • ULTRIX • BSD UNIX

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