18 Dec
2001
18 Dec
'01
7:52 a.m.
From: Richard Erlacher <edick(a)idcomm.com>
Yup! That's already been pointed out ... I made
the choice to use the
Western
MFM-capable part back in '78 and never looked back.
I let someone else
tell me
why, but I never regretted it. The process with the
Western part is
apparently
the same, though there was something critical that the
NEC part didn't do.
Maybe it had to do with altering the gap lengths in order to accomodate an
extra
sector, or some such. Of course, possible or not, I
never ended up doing
that
either.
Gaps are programmable too. There are two things the 765 will not do:
Munged
wacky formats like using deleted address mark for address mark {you can post
format with deleted data} and it was not designed to pump out all the raw
bits/splices/marks from the media.
Things it did do that the WD never had: Multiple seeks or recals, timing
for the
stepper, head load delay, head settle delay.
The biggest difference: register based programming vs command packet to a
"port".
I've used both and someplaces one or the other is better. On the whole the
WD
parts always seemed to be first generation. The upside for the 765 based
was
the very highly integrated super chips like the 36c766 and later.
Allison