Path: utzoo!utgpu!watmath!iuvax!uxc.cso.uiuc.edu!tank!mimsy!chris
From: chris@mimsy.UUCP (Chris Torek)
Newsgroups: comp.unix.wizards
Subject: Re: Trashed Disk Labels Under Sun OS 3.5
Message-ID: <18969@mimsy.UUCP>
Date: 10 Aug 89 01:18:31 GMT
References: <5253@wiley.UUCP>
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
Lines: 15

In article <5253@wiley.UUCP> trwarcadia!simpson@usc.edu (Scott Simpson) writes:
>How come when I mount all of the disk as swap or anything in an 'a'
>partition on a local Micropolis 1355 disk connected to one of our
>clients the disk label gets trashed?

SunOS starts swap space at sector 0 of the swapon partition.  The label
is in disk sector 0.  Thus, SunOS will swap on top of the label if the
partition begins at disk sector 0.

4.3BSD-tahoe starts swap space at sector CLSIZE of the swapon
partition, so it never overwrites the first sector (since CLSIZE is at
least 1).  See /sys/sys/vm_swap.c, routine swfree() (when dvbase==0).
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163)
Domain:	chris@mimsy.umd.edu	Path:	uunet!mimsy!chris