Path: utzoo!attcan!uunet!mcsun!unido!mikros!mwtech!martin
From: martin@mwtech.UUCP (Martin Weitzel)
Newsgroups: comp.unix.i386
Subject: Floppy formats under 386/ix
Message-ID: <830@mwtech.UUCP>
Date: 3 Jul 90 08:09:38 GMT
Reply-To: martin@mwtech.UUCP (Martin Weitzel)
Organization: MIKROS Systemware, Darmstadt/W-Germany
Lines: 32

As I understand, the `official' manuals for 386/ix 2.0.2 are
the ones I can buy from AT&T or Prentice Hall. The "UNIX System
V/386 System Administrator's Reference Manual" specifies in
FD(7) the names for floppy disk devices.

According to the list given there the name "/dev/rdsk/f05qt" means
`5-1/4", 720 KB'. But if I check out the device-number pair, I find
that this name rather belongs to 3-1/2", 1.44 MB.

Needless to say (and as I knew for long), I can't use 5-1/4", 720 KB
floppies on 386/ix. Now my questions:

1) Which is wrong - the floppy driver of 386/ix or the manuals?

2) Will 5-1/4", 720 KB Floppies be supported in Release 2.2
   (Note: This format is one of the "standard exchange formats"
    of X/Open.)

A related question: Can I change the floppy driver for very
special needs? As I understand, most of the floppy driver code is
driven by some tables in the kernel(%) which specify starting and
ending cylinder, number of sectors, density of tracks, etc. May
this table be somehow modified before linking the kernel or can
it be patched at run-time? (BTW: On some other UNIX system I know,
there is *one* entry in the floppy driver tables which can be changed
with an `ioctl' at runtime - not a bad idea to support arbitrary
floppy formats. I'm curious if FDSPARAM/FDGPARAM are something similar.)

%: Hint for those who want to join into this discussion: Have a look at
"/usr/include/sys/gendev.h" around line 530 and "/usr/include/sys/fd.h".
-- 
Martin Weitzel, email: martin@mwtech.UUCP, voice: 49-(0)6151-6 56 83