PDP-11/24 - Revision history

Jnc: /* External links */ +pdp11 processor handbook

2024-02-29T21:37:22Z

‎External links: +pdp11 processor handbook

Jnc: +New category

2024-02-06T14:05:44Z

+New category

Jnc: /* Implementation details */ custom CPU slot

2022-05-31T03:30:51Z

‎Implementation details: custom CPU slot

Jnc: +img (was on wrong page)

2022-04-11T06:10:49Z

+img (was on wrong page)

Jnc: +/- 12V only in the BA11-A version

2022-01-18T02:11:02Z

+/- 12V only in the BA11-A version

Jnc: better organization

2022-01-15T11:20:38Z

better organization

Jnc: /* External links */ avoid redir

2022-01-14T23:12:55Z

‎External links: avoid redir

Jnc: +EK-11024-TM-003

2022-01-14T23:08:34Z

+EK-11024-TM-003

Jnc: +backplane NPG details

2021-11-17T16:34:43Z

+backplane NPG details

Jnc: /* Packaging */ clarify

2020-03-02T02:57:31Z

‎Packaging: clarify

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 ** [http://www.bitsavers.org/pdf/dec/pdp11/1124/MP01018_Rev_F_11-24_Engineering_Drawings_Mar84.pdf 11/24 Field Maintenance Print Set] (MP01018)
 * [http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/dload/EK-11024-TM-003.pdf PDP-11/24 System Technical Manual] (EK-11024-TM-003)
 {{Nav PDP-11}}

← Older revision		Revision as of 14:05, 6 February 2024
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	[[Category: UNIBUS PDP-11s]]		[[Category: UNIBUS PDP-11s]]
		+	[[Category: Extended UNIBUS]]

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 ===Implementation details===
-The -11/24 used a custom 9-slot [[backplane]] ([[DEC part number]] 54-13817); slot 1 was for the CPU, slot 2 could hold either EUB memory or the UNIBUS map; slots 3-6 could hold either EUB memory or UNIBUS [[Small Peripheral Controller|SPC]] devices. Slots 7-8 were ordinary UNIBUS [[Modified UNIBUS Device|MUD]]/SPC slots, and slot 9 was an ordinary UNIBUS SPC/UNIBUS Out slot.
+The -11/24 used a custom 9-slot [[backplane]] ([[DEC part number]] 54-13817, assembly 70-16905); slot 1 was a custom slot for the KDF11-U CPU, slot 2 was likewise custom, and could hold either EUB memory or the KT24 UNIBUS map; slots 3-6 could hold either EUB memory or UNIBUS [[Small Peripheral Controller|SPC]] devices. Slots 7-8 were ordinary UNIBUS [[Modified UNIBUS Device|MUD]]/SPC slots, and slot 9 was an ordinary UNIBUS SPC/UNIBUS Out slot.
 The EUB and UNIBUS address lines were kept totally separate in all the slots which supported the EUB (1-6); the 22-bit EUB address bus is carried on the EUB address lines (on [[DEC edge connector contact identification|connectors A-B]]), and the 18-bit UNIBUS addresses are  carried on the SPC address pins (on connector E).

← Older revision		Revision as of 06:10, 11 April 2022
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		+	[[Image:pdp11-24.jpg\|250px\|thumb\|right\|PDP-11/24 in BA11-A box]]
		+
	The '''PDP-11/24''' was the last low-end [[UNIBUS]] [[PDP-11]] system; it used the [[KDF11-U CPU]]. Like the earlier [[PDP-11/44]], the -11/24 supported up to 4 Mbytes of [[main memory]], using the [[Extended UNIBUS]] between the [[CPU]] and memory; all devices were attached to a semi-separate (see below) UNIBUS.		The '''PDP-11/24''' was the last low-end [[UNIBUS]] [[PDP-11]] system; it used the [[KDF11-U CPU]]. Like the earlier [[PDP-11/44]], the -11/24 supported up to 4 Mbytes of [[main memory]], using the [[Extended UNIBUS]] between the [[CPU]] and memory; all devices were attached to a semi-separate (see below) UNIBUS.

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 ===Packaging===
-The -11/24 came in two different cabinets, the 5-1/4 inch high [[BA11-L mounting box|BA11-L]] and the 10-1/2 inch [[BA11-A mounting box|BA11-A]] - the same mounting box as used in the -11/44.
+The -11/24 came in two different cabinets, the 5-1/4 inch high [[BA11-L mounting box|BA11-L]] and the 10-1/2 inch [[BA11-A mounting box|BA11-A]] - the latter being the same mounting box as used in the -11/44.
-The former is specified to use either the -UA (120VAC input) or -UB (240V) versions of the [[H777 Power Supply]] for the -11/24, to provide the 12V needed for the [[MS11-M MOS memory|MS11-M]] EUB memory - although the manual does not mention the use of this memory in the -11/24. The two memories which are mentioned - the [[MS11-L MOS memory|MS11-L]] (which can run on 15V) and [[MS11-P MOS memory|MS11-P]] (which only uses +5V) - should be able to use any H777 variant.
+The former is specified to use either the -UA (120VAC input) or -UB (240V) versions of the [[H777 Power Supply]] for the -11/24, to provide +/- 15 [[voltage|volt]] power for use by its [[EIA RS-232 serial line interface|RS232]] [[asynchronous serial line]]s.
 The CPU backplane of the -11/44 uses unique [[Flexprint cable]]s for power, which go to special connections on [[bus bar]]s in the BA11-A's [[power supply]], though, not the standard [[DEC power distribution connectors]] used by the -11/24 backplane (as in the BA11-L mounting box). So, the -11/24 needs a special 'Power Distribution Board' (part # 54-13815) for the BA11-A, which mounts to the bus bars and provides the needed connectors.

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 The '''PDP-11/24''' was the last low-end [[UNIBUS]] [[PDP-11]] system; it used the [[KDF11-U CPU]]. Like the earlier [[PDP-11/44]], the -11/24 supported up to 4 Mbytes of [[main memory]], using the [[Extended UNIBUS]] between the [[CPU]] and memory; all devices were attached to a semi-separate (see below) UNIBUS.
-An optional UNIBUS Map board, the [[KT24 UNIBUS map option|KT24]], provided a path between the UNIBUS and the EUB for access to all of memory for UNIBUS [[Direct Memory Access|DMA]] devices; without it, the UNIBUS [[address space]] was statically mapped across to the low 248 Kbytes of EUB main memory, using a cross-connection path on the [[Central Processing Unit|CPU]] board. If no KT24 was present, the CPU detected its absence, and turned on a set of drivers on the CPU card which gated the address from the UNIBUS through to the EUB.
+An optional [[UNIBUS map]] board, the [[KT24 UNIBUS map option|KT24]], provided a path between the UNIBUS and the EUB for access to all of memory for UNIBUS [[Direct Memory Access|DMA]] devices; without it, the UNIBUS [[address space]] was statically mapped across to the low 248 Kbytes of EUB main memory, using a cross-connection path on the [[Central Processing Unit|CPU]] board. If no KT24 was present, the CPU detected its absence, and turned on a set of drivers on the CPU card which gated the address from the UNIBUS through to the EUB.
 ==System bus structure==
-As mentioned, the -11/24 used an EUB for the bus between the main memory and the CPU, and the UNIBUS for the bus between the CPU and devices. The two buses were not entirely separated: they shared a set of data lines, but each bus had a separate complete set of address lines.
+As mentioned, the -11/24 used an EUB for the bus between the main memory and the CPU, and the UNIBUS for the bus between the CPU and devices. The two buses were not entirely separated: they shared a set of data lines, but each bus had a separate complete set of address lines. (The lower address lines cannot be shared between the two busses, since the UNIBUS map provides arbitrary mapping from UNIBUS addresses to main memory addresses; so there are no lines which are guaranteed to have the same values, to allow them to be shared between the two busses.)
 Either the CPU, or the optional KT24, provided a path for addressing information to flow from the UNIBUS to the EUB, for DMA access to main memory by devices.
@@ Line 15: / Line 15: @@
 The -11/24 used a custom 9-slot [[backplane]] ([[DEC part number]] 54-13817); slot 1 was for the CPU, slot 2 could hold either EUB memory or the UNIBUS map; slots 3-6 could hold either EUB memory or UNIBUS [[Small Peripheral Controller|SPC]] devices. Slots 7-8 were ordinary UNIBUS [[Modified UNIBUS Device|MUD]]/SPC slots, and slot 9 was an ordinary UNIBUS SPC/UNIBUS Out slot.
-The EUB and UNIBUS address lines were kept totally separate in all the slots which supported the EUB (1-6); the 22-bit EUB address bus is carried on the EUB address lines (on [[DEC edge connector contact identification|connectors A-B]]), and the 18-bit UNIBUS addresses are  carried on the SPC address pins (on connector E). (The lower address lines cannot be shared between the two busses, since the UNIBUS map provides arbitrary mapping from UNIBUS addresses to main memory addresses; so there are no lines which are guaranteed to have the same values, to allow them to be shared between the two busses.)
+The EUB and UNIBUS address lines were kept totally separate in all the slots which supported the EUB (1-6); the 22-bit EUB address bus is carried on the EUB address lines (on [[DEC edge connector contact identification|connectors A-B]]), and the 18-bit UNIBUS addresses are  carried on the SPC address pins (on connector E).
 The data lines were cross-connected between the EUB and SPC/UNIBUS. That is because the DEC EUB memory boards pick up the data lines on connector A, whereas UNIBUS SPC devices must get them on connector C - and the memory/SPC slots of the -11/24 backplane can hold either.

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 * [http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/dload/EK-11024-TM-003.pdf PDP-11/24 System Technical Manual] (EK-11024-TM-003)
-{{PDP-11}}
+{{Nav PDP-11}}
 [[Category: UNIBUS PDP-11s]]

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 The former is specified to use either the -UA (120VAC input) or -UB (240V) versions of the [[H777 Power Supply]] for the -11/24, to provide the 12V needed for the [[MS11-M MOS memory|MS11-M]] EUB memory - although the manual does not mention the use of this memory in the -11/24. The two memories which are mentioned - the [[MS11-L MOS memory|MS11-L]] (which can run on 15V) and [[MS11-P MOS memory|MS11-P]] (which only uses +5V) - should be able to use any H777 variant.
-The backplane of the latter uses unique [[Flexprint cable]]s for power, which go to special connections on [[bus bar]]s in the BA11-A's [[power supply]], though, not the standard [[DEC power distribution connectors]] used by the -11/24 backplane (as in the BA11-L mounting box). So, the -11/24 needs a special 'Power Distribution Board' (part # 54-13815) for the BA11-A, which mounts to the bus bars and provides the needed connectors.
+The CPU backplane of the -11/44 uses unique [[Flexprint cable]]s for power, which go to special connections on [[bus bar]]s in the BA11-A's [[power supply]], though, not the standard [[DEC power distribution connectors]] used by the -11/24 backplane (as in the BA11-L mounting box). So, the -11/24 needs a special 'Power Distribution Board' (part # 54-13815) for the BA11-A, which mounts to the bus bars and provides the needed connectors.
 ==Memory configuration limits==