11 Nov
2010
11 Nov
'10
10:32 p.m.
On 11 Nov 2010 at 11:43, Rich Alderson wrote:
A minimal System/360 system has a multiplexor channel
for unit-record
devices (card readers and punches, line printers) and a selector
channel for high-speed devices (tapes, direct-access storage devices).
These channels are the equivalent of the CDC PPUs, with DMA capability
and their own programs (started by the CPU, and left to their own
devices, so to speak ;-).
Having written my share of CCW chains in the past, I'd say
"analogous" but not "equivalent"--unless you've seen a
command-line
parser or COBOL compiler written in CCWs...
(Yes, a PPU COBOL compiler actually existed--done as a "project" by a
couple of COBOL freaks.)
--Chuck