[conspire] Floppy drive on today's Linux

Rick Moen rick at linuxmafia.com
Mon Jun 7 17:35:33 PDT 2010


Quoting Roger Chrisman (roger at rogerchrisman.com):

> 3) I turned Floppy Drive on in BIOS. (I had it turned off previously
> because I wasn't using the floppy drive.)

This is actually the key step.  It's what fixed your problem.

For lack of BIOS-enabling of the floppy port, the hardware could not be
reached.  Therefore, even if your system has mtools, kernel support for
floppies, and a /dev/fd0 device file, it won't be able to talk to the
drive, because the motherboard itself cannot.  All of those problems
vanished when you flipped the BIOS config item to 'enabled'.

> 4) And this works!:
> sudo mount /dev/fd0 /mnt

You'll find that the 'mtools' approach (mdir, mformat, etc.) now works,
too, and is _usually_ preferable because it eliminates the need for
mounting and umounting.  (It works only for FAT-formatted floppies,
though.)

> The Xubuntu desktop icon works to access the disk _only_ after we
> mount it with 
> sudo mount /dev/fd0 /mnt

Well, I wouldn't know _offhand_ why the Xubuntu automounter has
problems.  It might be trying to access /dev/fd0 as _you_, so it might
very well be in your interest to ensure that you are a member of the
group (see:  /etc/group) that owns /dev/fd0.

Here's what I'm talking about on the Debian box in front of me:

[rick at linuxmafia]
~ $ ls -l /dev/fd0

brw-rw---- 1 root floppy 2, 0 2010-01-19 12:06 /dev/fd0
[rick at linuxmafia]
~ $ grep floppy /etc/group

floppy:x:25:rick
[rick at linuxmafia]
~ $ 

Notice that the ownership of device file /dev/fd0 is owner=root,
group=floppy.  Notice that the "floppy" line in /etc/group includes
'rick' after the last colon, making 'rick' a member of that group.
Therefore, user 'rick', and any process running with that user's
authority, has read + write permissions to the floppy.

By contrast, 'world' = all other users has permissions '---', i.e., 
no permissions at all.


By the way, one of the lessons of this is:  If something doesn't seem to
be working, see if the root user can do it.  If the root user can, but
other users cannot, then it's almost certainly an ownership/rights
problem.





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