MJ11 memory system - Revision history

Jnc: rm dup cat

2024-02-06T01:22:15Z

rm dup cat

Jnc: Better category

2024-02-06T01:18:19Z

Better category

Jnc: +New Category

2024-02-05T23:55:08Z

+New Category

Jnc: rm bloat

2023-07-02T16:56:43Z

rm bloat

Jnc: +imgs

2021-12-24T12:51:08Z

+imgs

Jnc: Emphasize uses modules in pairs

2021-10-07T18:49:20Z

Emphasize uses modules in pairs

Jnc: +core stack img

2021-10-07T18:39:53Z

+core stack img

Jnc: /* Further reading */ fiche only

2021-09-27T13:36:52Z

‎Further reading: fiche only

Jnc: /* Further reading */ +MJ11 Memory System Maintenance Manual

2021-09-27T12:35:00Z

‎Further reading: +MJ11 Memory System Maintenance Manual

Jnc: /* Implementation */ Add board layout

2021-09-26T11:59:11Z

‎Implementation: Add board layout

← Older revision		Revision as of 01:22, 6 February 2024
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	[[Category: PDP-11 Memories]]		[[Category: PDP-11 Memories]]
−	~~[[Category: DEC Memories]]~~

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 * [https://deramp.com/downloads/mfe_archive/011-Digital%20Equipment%20Corporation/08%20PDP-11/05%20Unibus%20Options/MJ11%201170%2016K%2032K%20Core%20Memory/01%20MJ11%20Documentation/MJ11-A%20Engineering%20Drawings/ MJ11-A Engineering Drawings]
-[[Category: PDP-11 Peripherals]]
+[[Category: PDP-11 Memories]]
 [[Category: DEC Memories]]

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 * [https://deramp.com/downloads/mfe_archive/011-Digital%20Equipment%20Corporation/08%20PDP-11/05%20Unibus%20Options/MJ11%201170%2016K%2032K%20Core%20Memory/01%20MJ11%20Documentation/MJ11-A%20Engineering%20Drawings/ MJ11-A Engineering Drawings]
-[[Category: PDP-11s]]
+[[Category: PDP-11 Peripherals]]
 [[Category: DEC Memories]]

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 * [http://www.bitsavers.org/pdf/dec/pdp11/1170/EK-MJ11-OP-001_UsersMan_Dec76.pdf MJ11 memory system user's manual] (EK-MJ11-OP-001)
 * [https://deramp.com/downloads/mfe_archive/011-Digital%20Equipment%20Corporation/08%20PDP-11/05%20Unibus%20Options/MJ11%201170%2016K%2032K%20Core%20Memory/01%20MJ11%20Documentation/MJ11-A%20Engineering%20Drawings/ MJ11-A Engineering Drawings]
 [[Category: PDP-11s]]
 [[Category: DEC Memories]]

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 The '''MJ11 memory system''' was a [[core memory|core]] [[main memory]] system for the [[PDP-11/70]]. It was 32 bits wide, to interface to the -11/70's Main Memory Bus, and provided byte [[parity]] (4 bits/double-[[word]]). Read, Write, and Exchange cycles were supported.
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 ==Implementation==
-It was housed in a [[BA11-K mounting box]], and used a custom 26-slot [[backplane]] ([[DEC part number]] 70-10497), holding a number of [[DEC card form factor|hex]] [[printed circuit board|boards]]. These included a pair of control boards - an M8149 transceiver board, and either an M8147 or M8148 control and timing board (the M8148 could only be used with 32KB core stack modules, whereas the M8147 could be used with either); the Main Memory Bus was carried on [[flat cable]]s, which plugged into [[Berg connector]] headers on the control cards. Data was stored on between 1 and 4 pairs of core stack sets.
+[[Image:M8149MJ11Trans.jpg|300px|thumb|right|M8149 Transceiver card]]
 A 32KB core stack set consisted of:
@@ Line 23: / Line 27: @@
 The 32KB stack set contains the same boards as those in the [[MM11-U core memory]]; the 64KB stack set contains the same boards as those in the [[MM11-W core memory]].
-[[Image:H224-C-core-stack.jpg|300px|thumb|right|H224-C core stack, showing flat cables]]
+[[Image:H224-C-core-stack.jpg|300px|thumb|right|H224-C core stack, showing inter-card flat cables]]
 In the 64KB set, the H224-C is connected to the G116/G236 cards with '[[over the back]]' flat cables, which carry the [[core memory#Technical details|sense/inhibit]] signals from the core stack board to the electronics board. This is possibly because the MJ11 backplane was designed for use with the MM11-U board set, and changes in the functional modularization may have made those connections unsuitable for use by the 64KB set.

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 The 32KB stack set contains the same boards as those in the [[MM11-U core memory]]; the 64KB stack set contains the same boards as those in the [[MM11-W core memory]].
-In the 64KB set, the H224-C is connected to the other two cards with '[[over the back]]' flat cables; this is possibly because the MJ11 backplane was designed for use with the MM11-U board set, and changes in the functional modularization may have made those connections unsuitable for use by the 64KB set.
+[[Image:H224-C-core-stack.jpg|300px|thumb|right|H224-C core stack, showing flat cables]]
 The H224-C core stack is connected to the G236 with a 20-pin cable, and to the G116 with three 40-pin connectors. The cable end on the G116/G236 end is a standard Berg header, but on the H224-C end, the cables are soldered directly to the board, not plugged into a connector.

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 ==Further reading==
-* ''MJ11 Memory System Maintenance Manual'' (EK-MJ11-MM-002) - not available
+* ''MJ11 Memory System Maintenance Manual'' (EK-MJ11-MM-002) - only available in microfiche
 ==External links==

← Older revision		Revision as of 12:35, 27 September 2021
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	* [[MK11 memory system]]		* [[MK11 memory system]]
		+
		+	==Further reading==
		+
		+	* ''MJ11 Memory System Maintenance Manual'' (EK-MJ11-MM-002) - not available

	==External links==		==External links==