Subject: Re: i386 floppy driver broken?
To: None <netbsd-bugs@NetBSD.ORG>
From: Matthias Drochner <drochner@zelux6.zel.kfa-juelich.de>
List: netbsd-bugs
Date: 05/01/1995 20:58:11
> [discussion about mapping floppy minor numbers <-> formats]

OK, the original question seems to be solved, but this leads me to
a related topic:
I'd like to have the floppy driver a little bit more general; i'd like
to read more formats then the predefined 7.

(Short explanation: We are heavily using the real-time OS "OS-9"
on diskless systems. It uses a unix-like fs with 256-byte sectors.
OS-9 can mount disks via NFS. Software usually comes on
floppy disks - no way to read them.)

To satisfy my needs, some changes in the driver are necessary:
1. more then 8 format letters - there are 5 bits left in the minor
  number (who has more then 16 floppy drives?)
2. different sector sizes (1 more entry in struct fd_type, change
  some calculations by the factor
  DEV_BSIZE / type->new_field_for_sectorsize ...)
3. track offset (new entry in struct fd_type) - track 0 is unused
  (not really important, this could be dealt with in the filesystem
  code as well).

I did these modifications (and the filesystem specific additions)
for NetBSD 1.0 some time ago, I'd upgrade to -current, but
don't like ihe idea of hacking every new driver release. So
I'm asking for more official support.

Perhaps there is a general need for alternate floppy formats.
(Is there nobody with old home computer/CP-M/PDP-11/
typewriter/xxx floppies?)

regards, Matthias
drochner@zelux6.zel.kfa-juelich.de