Date: Sat, 2 Oct 1999 21:04:59 +0200 (CEST) From: Oliver Fromme <olli@dorifer.heim3.tu-clausthal.de> To: freebsd-hackers@FreeBSD.ORG Subject: Re: 2.88Mb floppies Message-ID: <199910021904.VAA16526@dorifer.heim3.tu-clausthal.de>
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Wilko Bulte wrote in list.freebsd-hackers:
> As Oliver Fromme wrote ...
> > I once programmed low-level FDC stuff under DOS, so I'm a bit
> > familiar with this... The difference between 1.44 and 2.88 Mb
> > floppies is that the latter use 36 sectors per track and twice
> > the data rate (1 MBit/s). So the entry should look like this:
> >
> > {36, 2, 0xff, 0x1b, 80, 5760, 1, FDC_125KBPS, 2, 0x6c, 1}
> >
> > Actually, there should be a #define FDC_1MBPS FDC_125KBPS
>
> Eh, I guess you mean:
>
> {36, 2, 0xff, 0x1b, 80, 5760, 1, FDC_1MBPS, 2, 0x6c, 1} ?
No, FDC_1MBPS is not defined (that's why I said that it
_should_ be defined).
Actually, FD controllers use a 2bit flag to indicate the
transfer speed, and traditional controllers interpreted those
four values as 125, 250, 300 and 500 kbps. Newer controllers
dumped the 125 kbps support and interpret the same bits as
1000 kbps. So using FDC_125KBPS is OK.
Beware, I have not actually tried this with FreeBSD, and there
might be bugs that prevent using 2.88 Mb floppies.
Regards
Oliver
--
Oliver Fromme, Leibnizstr. 18/61, 38678 Clausthal, Germany
(Info: finger userinfo:olli@dorifer.heim3.tu-clausthal.de)
"In jedem Stück Kohle wartet ein Diamant auf seine Geburt"
(Terry Pratchett)
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