Difference between revisions of "PDP-10 memories"

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Most the memory units had a configuration panel which allowed ports to be enabled, and set the memory's address (often independently for each port); similarly, some level of interleaving could be set.
 
Most the memory units had a configuration panel which allowed ports to be enabled, and set the memory's address (often independently for each port); similarly, some level of interleaving could be set.
 +
 +
As was common with machines of that era, compatible PDP-10 main memory units were produced and sold by manufacturers other than [[Digital Equipment Corporation|DEC]]; some (but by no means all) are listed below.
  
 
==Memory systems==
 
==Memory systems==
  
18-bit external:
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18-bit external (DEC):
  
 
* [[MA10 core memory|MA10]]
 
* [[MA10 core memory|MA10]]
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* [[MD10 core memory|MD10]]
 
* [[MD10 core memory|MD10]]
  
22-bit external:
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18-bit external (others):
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* [[Fabritek Core Memory]]
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 +
22-bit external (DEC):
  
 
* [[ME10 core memory|ME10]]
 
* [[ME10 core memory|ME10]]
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* [[MH10 core memory|MH10]]
 
* [[MH10 core memory|MH10]]
  
Internal:
+
22-bit external (others):
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* [[Ampex ARM10|Ampex ARM-10L]]
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 +
Internal (DEC):
  
 
* [[MA20 core memory|MA20]]
 
* [[MA20 core memory|MA20]]
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* [[MG20 MOS memory|MG20]]
 
* [[MG20 MOS memory|MG20]]
  
The first two groups are all multi-port (generally 4 ports per memory system in the first group, and 8 in the second). The last group were for the later final KL10s (models KL10-E and KL10-R). All except the MF20 and MG20 were core.
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Internal (others):
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* [[Ampex ARM20]]
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The first two groups are all multi-port (necessary to allow [[mass storage]] on [[channel]]s to do [[Direct Memory Access|DMA]]; generally 4 ports per memory system in the first group, and 8 in the second). The last group were for the later final KL10s (models KL10-E and KL10-R); all the DEC ones except the MF20 and MG20 were core.
  
 
[[Category: PDP-10 Memories]]
 
[[Category: PDP-10 Memories]]

Revision as of 10:59, 22 April 2022

PDP-10 memories were generally all multi-port memory units. The PDP-10 CPU used one port (one per CPU in multi-processor systems); the others are used by channels for mass storage, such as disks. Interleaving was generally supported between units; usually in pairs, or sometimes groups of four. All except the very last ones were core, and supported parity for error detection; the others were MOS DRAM, and used ECC to protect the memory contents.

KI-type memory bus Quick Latch connector (in unlatched position)

There were three generations of main memory bus (which ran sequentially through memory units to a terminator), and memory units to them. The first two were the so-called 'external memory bus', in KA (18-bit address) and KI (22-bit) forms (for the KA10, and KI10 and early KL10, respectively), although they also had protocol differences. The last was the 'internal memory bus', the 'S-Bus'. (For the later KL10s, a later version of the S-Bus, the X-Bus, differed only in the logic family it interfaced to.) The differences between the two external bus types required a KI10-M Memory Bus Adapter if KA-bit units were to be attached to a KI10. Similarly, KI-type units could be attached to the S-Bus using a DMA20 Memory Bus Adapter.

The S-Bus (and the later version, the X-Bus, used with MOS 'internal' memory) performs memory transfers in blocks of up to four words, so that four words can be read in any cycle; the block can start with any word within the block. The KL10 contains a pair of S-Busses, designated 0 and 1.

Most the memory units had a configuration panel which allowed ports to be enabled, and set the memory's address (often independently for each port); similarly, some level of interleaving could be set.

As was common with machines of that era, compatible PDP-10 main memory units were produced and sold by manufacturers other than DEC; some (but by no means all) are listed below.

Memory systems

18-bit external (DEC):

18-bit external (others):

22-bit external (DEC):

22-bit external (others):

Internal (DEC):

Internal (others):

The first two groups are all multi-port (necessary to allow mass storage on channels to do DMA; generally 4 ports per memory system in the first group, and 8 in the second). The last group were for the later final KL10s (models KL10-E and KL10-R); all the DEC ones except the MF20 and MG20 were core.