1 Jan
2011
1 Jan
'11
6:42 p.m.
Isn't there also an issue of recording direction of flippy discs being oppos=
ite of expected? Or are disc controllers smart enough to account for this? S=
eems like this would also affect interleave as well as the per-sector data r=
eversal.
Yes, if you're usinga normal disk controller chip. But the diskferret
doesn't do that AFAIK, it reads and stores the raw bitstream from the
drive which is later analysed by software. So it would be possible to use
said software to reverse the bitstream before decoding it.
AFAIK no disk controller chip could ever handle a reversed bitstream, though
There have been apocryphal stories of large ('washing machine') hard
drifes spinning backwards, Some such drives have 3 phase motors, and of
course if you swap roiund a pair of the phase wires, the motor runs
backwards. Such drives, apparently, pass all diagnostics, but the packs
can't be read on other drives. I am not sure I believe said stories, I
would think the heads would be vey unstable under such conditions and
would crash very easily.
Thinking about it, I am suprised no manufacturer ever reversed the
spidnle direction of their floppy drives as a way to prevend disk
interchangeablility wiht other machines. At least one manufacturer
believed that disk interchanagability would lead to software piracy and
did various silly things to try to prevent it.
-tony