floppy low level format question

From: Tom Jennings <tomj_at_wps.com>
Date: Mon Jun 14 13:40:31 2004

>
> > Question is, is this a standard? I mean, for any disk using MFM or FM
> > recording are these bit patterns going to be the same?

Standards schmandards, we have lots of standards!

If you want to read any possible floppy format, then the only thing you
can rely on is transitions to/from 0/1, and the DSP approach is about
right.

As others point out, the WD chips are the sloppiest in terms of what
their state machines insist on the NEC 765 is a pain.

PS: The old Micromation floppy controller (CP/M 1.4 days) used NEITHER
chip family, did their own formatin LS TTL, and practically no one can
read them.

You can probably do all this in a PC sound card these days!
Received on Mon Jun 14 2004 - 13:40:31 BST