Date   : Tue, 11 Oct 2005 08:05:09 +0100
From   : Mike Tomlinson <mike@...>
Subject: Re: 3.5" Floppy For A Master

In article <434AF3F0.90401@...>, Jules Richardson <julesrichards
onuk@...> writes

>Jumpering, cabling and CMOS issues aside though, isn't the main issue 
>that the PC's floppy hardware only ever really supported MFM data 
>recording

Yes.

> (except for the really early days) and so won't support the FM 
>needed to read/write DFS disks?

Very few PC controllers will _write_ FM successfully.  Many (probably
the vast majority) can be persuaded to read it.  The notes that
accompany the version of FDC adapted for BBC discs indicate that writing
FM can be achieved with some ISA controllers.

Jason Watton's notes accompanying OmniDisk and OmniFlop are well worth
reading.

>By all accounts, new PC 
>motherboards seem to (strangely) stand a better chance of working than 
>anything built between (say) 1990 and a couple of years ago.

That seems to be the case, though I haven't tried new machines, say
within the last five years.  I'd suggest the best chances of success
would be with a Pentium I or II based machine with a basic onboard
multi-I/O controller chip.  I found that if Linux identified the floppy
controller as a "post-1991 82077" during the hardware probe, it was
highly likely to work reliably with at least one of the various disk-
reading utilities. ("dmesg | grep post\-" gets you this info.)