Date: Fri, 14 Aug 2020 22:00:54 +0200 From: Polytropon <freebsd@edvax.de> To: User Questions <freebsd-questions@freebsd.org> Cc: Lowell Gilbert <freebsd-questions-local@be-well.ilk.org>, Christoph Kukulies <kuku@kukulies.org> Subject: Re: 5.25" Floppy disk drive not recognized Message-ID: <20200814220054.9d10cb7e.freebsd@edvax.de> In-Reply-To: <44imdl80ws.fsf@be-well.ilk.org> References: <46FFA8F9-90AA-42DE-8E8B-CA4383CA7AC6@kukulies.org> <20200814101021.c71f6c23768a5bef685739fe@sohara.org> <20200814071030.3f319e5a@scorpio.seibercom.net> <76A64DE1-B61B-405E-A623-C886819E1977@kukulies.org> <44imdl80ws.fsf@be-well.ilk.org>
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On Fri, 14 Aug 2020 15:47:47 -0400, Lowell Gilbert wrote:
> When floppy drives were common, they were
> (typically) strictly ISA devices and so sometimes required configuration
> at the driver level. See fdc(4), although generally I remember being
> able to do all of the magic through fdcontrol(8).
The use of fdcontrol is very important if the disk in question
is not what the drive thinks it should be. :-)
> Because your media are old, they are likely to be troublesome, and
> fdread(1) may save you time in getting the maximum amount of data off
> the floppies.
There are also forensic tools like ddrescue (or dd_rescue?) that
can adjust retries and read block size (default from 512 bytes
down to 1 byte per try) if it needs to be.
> Be careful with the disks that have your precious data by
> experimenting with ones you're willing to sacrifice, and don't read or
> write the important ones any more than necessary.
Also make sure the drive is clean, the head is undamaged.
> > Also # cat /dev/fd0 >dump
> > cat: /dev/fd0: Device not configured
> >
> > Why?
>=20
> Did that ever work?
More or less (in this case, less, which is more, couldn't resist):
% less -f /dev/fd0
=EB<<90>MSWIN4.1^@^B^A^A^@^B=E0^@@^K=F0
^@^R^@^B^@^@^@^@^@^@^@^@^@^@^@)=C1=A8<83>
$ FAT12 =FA3
[...]
And so on. You can use cat with something like this:
% cat /dev/fd0 | xxd
0000000: eb3c 904d 5357 494e 342e 3100 0201 0100 .<.MSWIN4.1.....
0000010: 02e0 0040 0bf0 0900 1200 0200 0000 0000 ...@............
0000020: 0000 0000 0000 29c1 a883 2420 2020 2020 ......)...$ =20
0000030: 2020 2020 2020 4641 5431 3220 2020 fa33 FAT12 .3
0000040: c98e d1bc fc7b 1607 bd78 00c5 7600 1e56 .....{...x..v..V
[...]
In the past, I've even used tar directly with floppies, with
aliases called "flop <file(s)>" and "unflop"... :-)
--=20
Polytropon
Magdeburg, Germany
Happy FreeBSD user since 4.0
Andra moi ennepe, Mousa, ...
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