Difference between revisions of "MA20 core memory"
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| − | The '''MA20''' was a [[core memory|core]] [[main memory]] system for the later [[PDP-10]]s, principally the mid-period [[KL10]]. An MA20 contained two memory controllers (numbered 0 and 1, or 2 and 3), each with up to four 16KW storage modules, for a maximum of 128KW; [[parity]] is provided to protect the memory contents. The [[access time]] is 1.00 µseconds, and the [[cycle time]] is 1.92 µseconds (both for the first [[word]] in a 4-word block, using four-way [[interleaving]]). | + | The '''MA20''' was a [[core memory|core]] [[main memory]] system for the later [[PDP-10]]s, principally the mid-period [[KL10]]; it connected to the KL10's so-called internal memory bus, the S-Bus. An MA20 contained two memory controllers (numbered 0 and 1, or 2 and 3), each with up to four 16KW storage modules, for a maximum of 128KW; [[parity]] is provided to protect the memory contents. The [[access time]] is 1.00 µseconds, and the [[cycle time]] is 1.92 µseconds (both for the first [[word]] in a 4-word block, using four-way [[interleaving]]). |
| − | + | Controllers 0 and 1 are connected to S-Bus 0, and controllers 2 and 3 to S-Bus 1. For interleaving, each controller is configured as to which addresses (out of the 4 in an S-Bus block) it will respond to; both 2-way and 4-way interleaving require controllers to be set to 'odd' or 'even'. In 4-way interleaving, in addition to two controllers being actuated at the same time, each controller can start two modules reading at the same time. | |
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| + | ==See also== | ||
| + | |||
| + | * [[MB20 core memory] | ||
[[Category: PDP-10 memories]] | [[Category: PDP-10 memories]] | ||
Revision as of 17:47, 11 April 2021
The MA20 was a core main memory system for the later PDP-10s, principally the mid-period KL10; it connected to the KL10's so-called internal memory bus, the S-Bus. An MA20 contained two memory controllers (numbered 0 and 1, or 2 and 3), each with up to four 16KW storage modules, for a maximum of 128KW; parity is provided to protect the memory contents. The access time is 1.00 µseconds, and the cycle time is 1.92 µseconds (both for the first word in a 4-word block, using four-way interleaving).
Controllers 0 and 1 are connected to S-Bus 0, and controllers 2 and 3 to S-Bus 1. For interleaving, each controller is configured as to which addresses (out of the 4 in an S-Bus block) it will respond to; both 2-way and 4-way interleaving require controllers to be set to 'odd' or 'even'. In 4-way interleaving, in addition to two controllers being actuated at the same time, each controller can start two modules reading at the same time.
See also
- [[MB20 core memory]
