6 Jun
2014
6 Jun
'14
3:08 p.m.
Apple switched to the Sony 3.5 inch drive well before
there was any solid
evidence that it would become an industry standard, so there was still no
particular need for Apple's 3.5 inch format to match anyone else's. IIRC
the only contemporary (1983-ish) almost-PC-compatible machines using the
Sony 3.5 inch drives did not actually use the later 720K standard format,
so even if Apple had used MFM rather than Woz GCR, it still wouldn't likely
have been compatible with anything significant, unless IBM had later
deliberately chosen to be compatible with Apple, which would have been
unlikely.
However, if Apple had sued a standard MFM controlelr at the normal data
rate the disk would have been readable by the controller in an IBM PC. It
would just ahvbe been a matter of programming to read/write said disk on
a CP (simialr ot the various CP/M, etc read/write utilites). As it is,
there is no way of getting a standard PC disk oontroller to read a Mac disk.
Incidentally, I came acorss a hald-length 8-bit ISA card the other day
with a few TTL ICs and a couple of PALs (I think, maybe ROM,s I didn't
read the numbers). On the bracked isa 19 bit D connector labelled 'Est
Drive' i nteh silkscreen. From what I can tell, this is a board to link
an external Mac dirve to a PC, I guess the circuitry is a non-integrated
Woz machine. I ahve no idea waht software wet with it, though.
-tony