Subject: Re: reviving /etc/disktab?
To: Jaromir Dolecek <>
From: Aymeric Vincent <>
List: tech-userlevel
Date: 01/10/2006 00:23:20
Quite a few answers came, so maybe it's time to speak up again.

Jaromir Dolecek <> writes:

> > Would there be interest in reviving /etc/disktab? I think it's nice to
> > have it common to all platforms, but it's a pity that it's empty.
> It's not empty - it contains entry for 3.5" floppy :)

Sure, and although it is certainly the most common format used by
people, it could also not be there.

In fact, I don't get the reason why we don't have the "asked for"
descriptions in /etc/disktab. It's not going to be overly big, it's
not processed often, so what's the point in keeping it ~empty?

> Optionally, we might change getdiskbyname(3) too look into
> the example disktab when an entry is not found in /etc/disktab.

I don't like this idea. Hardcoding an examples directory into a
utility sounds backward to me, and Jason's remark is even better.

And now that my thoughts are clearer on the subject, the only thing
which makes Amiga file systems specific is that the cpg field in the
disklabel is abused to store the number of reserved blocks at the
beginning of a partition. Number which in turn must be used to find
the root block of the partition.

That number is partition specific and really belongs in the
"disklabel" (indeed it is in the Rigid Disk Blocks on the Amiga),
although there is no provision for this notion in BSD disklabels
AFAIK. Anyhow we can't specify this parameter to vnconfig unless we
use a disktab(5) entry.

Otherwise, although it could be convenient, I don't like the idea of
adding a ("redundant") option to mount_ados(8) to specify the bits we
need to get to the root block.

Thanks for all the input so far. I would still like to see the Amiga
floppy entries in /etc/disktab, but I will not advocate it further.