6 Jan
2002
6 Jan
'02
2:41 p.m.
On Sun, 6 Jan 2002, Richard Erlacher wrote:
For that PDP-8 controller, it would be useful to know
the precise timing
relationship between the sector pulse and the next valid bit, including the
jitter. Once that's know, the recovery of data should be straightforward.
By looking at the timing diagram I have, the sync pulse falls as the first
bit of data starts. I'm not sure how correct that is, but I am sure that
the first rising edge on the data line following the falling edge of the
sector pulse it the start of the first data bit. After that, there are
another 24 '0' bits (so the data will follow the clock). I found a
copy of the manual at:
http://www.spies.com/~aek/pdf/dec/pdp8/EK-RL8A-TM.pdf
I would like to be able to also write data back onto the disk pack, so
that you could create a real disk from an image, and an image from a real
disk on a peecee (or other box some1 writes a driver for).
-- Pat