At Wed, 15 May 1996 05:25:50 EDT, der Mouse writes:
>> >> Ah, so that's why I never could get my system to work with the swap
>> >> at the beginning of the disk!
>> > No, swap at the "beginning of the disk" will usually cause the disk
>> > label to be overwritten [...]
>> 
>> That's what I thought too, when I first heard of this problem.  But if
>> you go look at swfree(), in vm/vm_swap.c, you'll see that it explicitly
>> makes sure that it doesn't "use the first cluster of the device in case
>> it starts with a label or boot block".  Now mind you, this code may be
>> broken somehow - tho it looks about right to me - but it's certainly
>> not as simple as just swapping over the disk label.

Just another data point: I've read that code too and thought it looked
right, but have had problems with i386 machines which swap on the
first cylinder of the boot disk (both wd and sd based ones) losing
their boot blocks.  The problems invariably went away if the swap
partition was shrunk so that it started from the second cylinder on
the disk instead.  Never had a chance to try and actually nail the bug
though.

Pete.