MA10 core memory
The MA10 was a core main memory system for the early PDP-10s, principally the KA10. An MA10 contained 16KW; parity was provided to protect the memory contents. It had an access time of 0.55 μseconds, and a cycle time of .93 µseconds. It connected to the so-called external memory bus of the 18-bit address form.
It was a multi-port memory, with 4 ports per memory system: each port can be independently disabled. The CPU uses one port (in a multi-processor system, one per CPU); the others are used by channels (such as a DF10) for mass storage such as disks.