Difference between revisions of "MS750 Memory System"

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m (External links: Another copy of 1/750 Memory System Technical Description)
m (External links: +L0016 image)
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* [https://manx-docs.org/collections/hcps/m8750.pdf M8750 Field Maintenance Print Set] (MP01398) - very faint scans
 
* [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)
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* [https://web.archive.org/web/20071004184324/http://computer-refuge.org/compcollect/dec/vax/11750/L0016-big.jpg L0016] - image
  
 
[[Category: VAX Memories]]
 
[[Category: VAX Memories]]
 
[[Category: CMI]]
 
[[Category: CMI]]

Revision as of 00:16, 17 May 2024

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

External links