Subject: Re: sd rereads
To: der Mouse <mouse@Rodents.Montreal.QC.CA>
From: Chris G. Demetriou <cgd@netbsd.org>
List: tech-kern
Date: 09/01/1999 19:30:54
der Mouse  <mouse@Rodents.Montreal.QC.CA> writes:
> > How about this for a compromise: on re-open, we check to see if the
> > diskabel block has changed and only recompute the in-core disklabel
> > if it's changed.
> 
> I think this is an excellent suggestion.  It seems to me that it
> addresses all the problems I've heard raised: set the in-core label
> without or writing the disk, and it's sticky.  Change the on-disk label
> "behind the back of the kernel" and the in-core label is updated from
> it on next first open.

It seems to me that this general notion is better accomplished
(without waste of memory or need for a checksum) by what I suggested.

	

> The only problem I can see is, are there any ports where "the disklabel
> block" is ill-defined?

well, i think they're all well-defined for some level of "well."
However, that can vary.  Also, it's less an issue of ports as
partitioning schemes.  do you keep the PC MBR, bsd disklabel, acorn
filecore partition table, amiga RDB...  Many or all of those can be in
different places.



cgd
-- 
Chris Demetriou - cgd@netbsd.org - http://www.netbsd.org/People/Pages/cgd.html
Disclaimer: Not speaking for NetBSD, just expressing my own opinion.