Difference between revisions of "PDP-10 memories"

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There were three generations of [[main memory]] [[bus]], and memory systems to attach to them, for the [[PDP-10]] line; the first two with the so-called external memory bus, in 18- and 22-bit [[address]] forms (for the [[KA10]], and [[KI10]] and early [[KL10]], respectively), and the last with the internal 'S-Bus' (for the later KL10). (Memory for the [[KS10]], which was ''sui generis'', is not covered here.)
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'''PDP-10 memories''' were generally all [[multi-port memory]] units. The [[PDP-10]] [[Central Processing Unit|CPU]] used one port (one per CPU in [[multi-processor]] systems); the others are used by [[channel]]s for [[mass storage]], such as [[disk]]s, to do [[Direct Memory Access|DMA]]. [[Memory interleaving|Interleaving]] was generally supported between units; usually in pairs, or sometimes groups of four. All except the very last ones were [[core memory|core]], and supported [[parity]] for [[error detection]]; the others were [[Metal Oxide Semiconductor|MOS]] [[Dynamic RAM|DRAM]], and used [[Error-correcting code|ECC]] to protect the memory contents.
  
There were minor differences between the two external bus types, requiring a [[KI10-M Memory Bus Adapter]] if 18-bit units are to be attached to a KI10. Similarly, 22-bit units can be attached to the S-Bus using a [[DMA20 Memory Bus Controller]].
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[[Image:KBusQCUnlatched.jpg|250px|thumb|left|KI-type memory bus Quick Latch connector (in unlatched position)]]
  
The S-Bus (and a later version, the X-Bus, used with [[Metal Oxide Semiconductor|MOS]] internal memory, such as the MF20) performs memory transfers in blocks of up to four [[word]]s, 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.
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There were three generations of [[main memory]] [[bus]] (which ran sequentially through memory units to a [[terminator]]), and memory units for 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 [[PDP-10 Memory Bus|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.)
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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]].
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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.
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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:
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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 memory]] (generally 4 ports per memory system in the first group, and 8 in the second); the [[Central Processing Unit|CPU]] uses one port, the others are used by [[channel]]s for [[mass storage]] such as [[disk]]s. All except the MF20 and MG20 were [[core memory]], and all supported [[parity]], and some level of [[interleaving]].
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Internal (others):
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* [[Ampex ARM20]]
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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 the DEC ones except the MF20 and MG20 were core.
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==See also==
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* [[PDP-10 Memory Bus]]
  
[[Category: PDP-10 memories]]
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[[Category: PDP-10 Memories]]

Latest revision as of 02:27, 31 July 2023

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, to do DMA. 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 for 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.

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 (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.

See also