Difference between revisions of "MS750 Memory System"

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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 Memory Modules
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* one to eight memory array modules
  
The Memory Controller connects to the [[CPU/Memory Interconnect]] [[bus]]; the Controller Module (either L0011, L0016, or L0022) resides in a custom slot in the [[Central Processing Unit|CPU]] [[backplane]], slot 10.
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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 Modules have their own backplane slots (the physical backplane itself, [[DEC part number]] 50-13821/70-16486, is shared with the CPU), 8 slots in total.
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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 Memory Modules = 2MB max.
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* L0011 - up to eight [[M8728]] 256KB memory array modules = 2MB max.
* L0016 - up to eight [[M8750]] 1MB Memory Modules = 8MB max.
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* L0016 - up to eight [[M8750]] 1MB memory array modules = 8MB max.
* L0022 - up to two [[M7199]] 4MB Memory Modules and six M8750 1MB Memory Modules = 14MB max.
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* 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)
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* [http://www.bitsavers.org/pdf/dec/vax/750/EK-MS750-TD-001_VAX-11_750_Memory_System_Technical_Description_198009.pdf VAX-11/750 Memory System Technical Description] (EK-MS750-TD-001)
 
* [http://www.bitsavers.org/pdf/dec/vax/750/EK-MS750-TD-001_VAX-11_750_Memory_System_Technical_Description_198009.pdf VAX-11/750 Memory System Technical Description] (EK-MS750-TD-001)
 
* [http://www.bitsavers.org/pdf/dec/vax/750/MP01404_750_Engineering_Drawings_Memory_Controller_198206.pdf Comet Memory Unit Field Maintenance Print Set] (MP01404) - covers the L0016
 
* [http://www.bitsavers.org/pdf/dec/vax/750/MP01404_750_Engineering_Drawings_Memory_Controller_198206.pdf Comet Memory Unit Field Maintenance Print Set] (MP01404) - covers the L0016
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* [https://manx-docs.org/collections/hcps/m8750.pdf M8750 Field Maintenance Print Set] (MP01398) - very faint scans
 
* [http://www.bitsavers.org/pdf/dec/vax/730/MP01270_11-730_Engineering_Drawings_198204.pdf 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)
 
* [http://www.bitsavers.org/pdf/dec/vax/730/MP01270_11-730_Engineering_Drawings_198204.pdf 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)
  
[[Category: VAXen]]
+
[[Category: VAX Memories]]
[[Category: DEC Memories]]
 

Revision as of 17:47, 7 June 2022

/750 backplane from behind, showing the slots occupied by the MS750 in the centre

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

256KB module

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)

1MB module


The earlier modules are also used with the MK11 memory system of the PDP-11/70.

External links