MS750 Memory System: Difference between revisions
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The '''MS750 Memory System''' is the [[main memory]] for the [[VAX-11/750]]; it consists of: | The '''MS750 Memory System''' is the [[main memory]] for the [[VAX-11/750]]; it consists of: | ||
* one Memory Controller (MCM) | * one Memory Controller module (MCM) | ||
* one to eight | * one to eight memory array modules | ||
The Memory Controller connects to the [[CPU/Memory Interconnect]] [[bus]] | The Memory Controller Module connects to the /750's [[CPU/Memory Interconnect]] [[bus]], and also to an internal memory bus - which does not seem to have a formal name - which runs to the memory array modules' slots. | ||
The Memory | The Memory Controller Module (either L0011, L0016, or L0022) resides in a custom slot in the main [[backplane]]; slot 10. The memory array modules have their own slots in a dedicated section of the backplane, 8 slots in total. (The physical backplane itself, [[DEC part number]] 50-13821/70-16486, is shared with the [[Central Processing Unit|CPU]]). | ||
==VAX-11/750 Memory Controllers== | ==VAX-11/750 Memory Controllers== | ||
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There were three different Memory Controller Modules for the MS750: | There were three different Memory Controller Modules for the MS750: | ||
* L0011 - up to eight [[M8728]] 256KB | * L0011 - up to eight [[M8728]] 256KB memory array modules = 2MB max. | ||
* L0016 - up to eight [[M8750]] 1MB | * L0016 - up to eight [[M8750]] 1MB memory array modules = 8MB max. | ||
* L0022 - up to two [[M7199]] 4MB | * L0022 - up to two [[M7199]] 4MB memory array modules and six M8750 1MB memory array modules = 14MB max. | ||
(14MB of Memory is the architectural limit of the VAX-11/750) | (14MB of Memory is the architectural limit of the VAX-11/750) | ||
Revision as of 21:26, 3 June 2022
The MS750 Memory System is the main memory for the VAX-11/750; it consists of:
- one Memory Controller module (MCM)
- one to eight memory array modules
The Memory Controller Module connects to the /750's CPU/Memory Interconnect bus, and also to an internal memory bus - which does not seem to have a formal name - which runs to the memory array modules' slots.
The Memory Controller Module (either L0011, L0016, or L0022) resides in a custom slot in the main backplane; slot 10. The memory array modules have their own slots in a dedicated section of the backplane, 8 slots in total. (The physical backplane itself, DEC part number 50-13821/70-16486, is shared with the CPU).
VAX-11/750 Memory Controllers

There were three different Memory Controller Modules for the MS750:
- L0011 - up to eight M8728 256KB memory array modules = 2MB max.
- L0016 - up to eight M8750 1MB memory array modules = 8MB max.
- L0022 - up to two M7199 4MB memory array modules and six M8750 1MB memory array modules = 14MB max.
(14MB of Memory is the architectural limit of the VAX-11/750)

The earlier modules are also used with the MK11 memory system of the PDP-11/70.
External links
- VAX-11/750 Memory System Technical Description (EK-MS750-TD-001)
- Comet Memory Unit Field Maintenance Print Set (MP01404) - covers the L0016
- 11/730-Z Field Maintenance Print Set (MP01270) - the M8750 is covered in MS730-C Field Maintenance Print Set (MP01366) (pp. 292-12 of the PDF)