I'm reading a paper about the architecture of the IBM system/360. There is a diagram which lays out the machine structure and implementation in the storage and control tables there is a metric which I don't understand which is Cycle \$\mu\$s:
What is this metric referring to ? Thanks for the help.
Ferrite core memory has to be read and then rewritten to retrieve data as the read operation is destructive.
The time to do this read followed by a write is referred to as the cycle time and is typically in the region of one microsecond to a few microseconds as shown in the right-hand column.
The Greek letter mu is the symbol shown to represent micro.
That's the cycle time of the CPU's memory (in microseconds)!
Yes, these memory systems ran at anywhere from 400 kHz to 1 MHz. Not exactly what you picture for "big iron" nowadays. You can add a column for bandwidth to the table:
MODEL WIDTH CYCLE BANDWIDTH
----- ----- ----- ---------
30 8 bits 2.0 us 500 kB/sec
40 16 bits 2.5 us 800 kB/sec
50 32 bits 2.0 us 2.0 MB/sec
60 64 bits 1.0 us 8.0 MB/sec
70 64 bits 1.0 us 8.0 MB/sec
