Date: Tue, 12 Sep 1995 13:12:46 +0000 From: "Peter May" <peter@osix.com.au> To: peter@taronga.com (Peter da Silva), hackers@freebsd.org Subject: Re: higher density diskettes Message-ID: <199509121259.MAA16918@thumper.osix.com.au>
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> In article <1337.810473461@critter.tfs.com>,
> Poul-Henning Kamp <phk@critter.tfs.com> wrote:
> >> Microsoft has switched to using so called DMF format
> >> (Distribution Media Format - 1,716,224 bytes 1.63 MB) on
> >> diskettes for the WIN95 distrubution disks.
>
> >This is very interesting. If it works for them, we can do that too.
> >The changes to the floppy-build procedure is rather few, but I still
> >suggest we hang in there until we hear how much trouble MS has with it...
>
> Anyone know what they're actually doing?
>
> Amiga uses standard MFM to get 1760KB on the same density disks, by leaving
> off the inter-sector gaps and reading and writing a track at a time. If you
> also leave off all the sector headers you get 1970KB (you nead one gap/sector
> header to mark the beginning of the data, or you'd be all the way
to 2000KB).
Just think of the buffer size you would need in the FD driver! At
least 26k of memory PER TRACK READ. And what about error detection?
Are we going to have the driver do CRC checks on data fields as well?
That should speed the performance of this already flaky driver up no
end! :-)
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