3 Nov
2005
3 Nov
'05
7:08 p.m.
Allison wrote:
Parity required an extra bit to stor the parity so
that it could be
compared on read. That bit may or may not have been part of the data
path logic.
But on the memory chips, that bit must have been readable for the
system hardware to do its comparions. I guess that the memory could
send back a GO/NO_GO signal but supplying the parity bit must
be easier and cheaper?
There was a spate of "fake parity" memory around some time in
the 90s. Quite why it was cheaper to add a chip that always
supplied "correct" parity rather than simply using additional
memory was something that I never understood. But if you
end up with one these "fake parity" memories it may well
cause your 9-bit machine some issues!!
Antonio
--
Antonio carlini
arcarlini at iee.org