Subject: Re: Disklabel ioctls (was Re: nore on disk ...)
To: None <tech-kern@NetBSD.ORG>
From: Ty Sarna <email@example.com>
Date: 11/17/1995 00:40:56
In article <m0tG7Py-0000jwC@moacs.indiv.nl.net>,
Waldi Ravens <firstname.lastname@example.org> wrote:
> I believe that, if support is added for all the vendor specific disk
> formats of currently supported platforms, it should be configurable.
> Otherwise it just adds a lot of hardly ever (or never) used code to
> the kernel. If, for example, in the current situation, I throw the
> AHDI compatibilty code out of disksubr.c, the size of the *disklabel()
> functions will decrease some 75-85%.
Oh, I thought that went without saying. I envisioned something along the
lines of the way emulations are handled now, with COMPAT_XXX options. I
imagine something along the lines of:
options DISKLABEL_BSD # traditional BSD disklabels
options DISKLABEL_MSDOS # msdos disklabels
options DISKLABEL_RDB # Amiga RDB labels
options DISKLABEL_AHDI # Atari disklabels
options DISKLABEL_SUN # SunOS labels
I imagine configured types would be held in a list like the emulation
list. They would be probed in order, and a default scheme (call it
"DISKLABEL_NONE", but it would probably not be optional) would be used
to make a label with just a c partition.
Ideally the scheme would also follow the proposed emul reorganization,
and allow a specific format to be specified to the write ioctl, to allow
a sparc to partition a DOS disk, or whatever (or for that matter, to
allow a DISKLABEL_NONE disk to be partitioned in the first place). If
no format was specified, the current format would be used.
Note that some disklabel formats would want to be read-only (as they are
already), since writing RDB (or AHDI, which sounds similar) labels would
be impractical, and in fact undesirable.