Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!mcsun!unido!mikros!mwtech!joerg
From: joerg@mwtech.UUCP (Joerg Werner)
Newsgroups: comp.os.minix
Subject: Re: Multiformat floppies Was: ST Minix 1.5 floppy driver and serial...
Message-ID: <1052@mwtech.UUCP>
Date: 15 Jan 91 14:16:16 GMT
References: <41322@nigel.ee.udel.edu>
Reply-To: joerg@mwtech.UUCP (Joerg Werner)
Organization: MIKROS Systemware, Darmstadt/W-Germany
Lines: 38

In article <41322@nigel.ee.udel.edu> archer%segin4.segin.fr@relay.prime.com (Vincent Archer) writes:
<Klamer Schutte -- Universiteit Twente <klamer@mi.eltn.utwente.nl> said:
<> ta_cook@eisvxe.moundst.mn.org (Thomas A. Cook) writes:
<> >Awhile back I remember some discussion about Minix for the ST being able to read
<> >the disk label to determine the size of the disk and the ablility to read 800Kb
<> >formatted (vs the 720Kb standard formatted) disks.
<>
[stuff deleted]
<
<The patch 3 to 1.5.10 does exactly this. I still haven't read a non-standard
<floppy with it, because everytime I use /dev/fd0 rather than sd0 or dd0, I get
<a nice "kernel panic:" :-(
<Something still wrong, I think :-)

Try a single side disk. This will (maybe:-) work. There is a little bug
inside the driver:-(. The number of cylinders isn't calculate correctly. It
must be divided by the number of heads!!


<> But there is a problem with this approach. You are creating a device which
<> can be resized according to the data you write to it.
<> (Suppose you have a 820k floppy. You write a tar file to the device /dev/dd0.
<> Now you have a tar file at the 82/10/2 style floppy. But...
<>  Next time you open the device, its bootblock( phys. block 0 ) will be
<>  corrupted (i.e. it will be the tar file header). So you can't read your
<>  information anymore)
<
<Correct. It was pointed out in the doc with the above-mentionned patch.
<

But such a device is very useful to read/write TOS-disks. I named it
/dev/a: and I call the tos-command with this name, i.e `tosdir -lR a:'.
The tos- command doesn't overwrite the bootblock, but recognizes all
(or may I say many) TOS-formats - no problems :-).


-- 
Joerg Werner, email: joerg@mwtech.UUCP, voice: 49-(0)6151-37 33 66