9 Dec
2003
9 Dec
'03
1:16 p.m.
On Tue, 9 Dec 2003, Eric Smith wrote:
The part of the ST-506 disk emulation that's of
most concern to me is
whether anything needs to be done about write precompensation. The
controller shifts the pulses on write to compensate for the peak
shifts that happen on magnetic media when flux changes are recorded
close together.
Is it not true that the precomp circuits are driven by head position
info - thus the 'solid' version (emulation) of any drive would just be
permanently 'stuck' in one mode or the other would the controller care, or
even know, what track and cylinder the actual 'data' were coming from?
I don't know if this would cause the emulator qua emulator to fail at
some perhaps subjective level - but I can't see where one would need to
actually legislate write precomp into a block of RAM.
Cheers and Best of the Season
John