Subject: Re: i386 1.4Q hangs nonrandomly?
To: None <>
From: Peter Seebach <>
List: current-users
Date: 01/28/2000 13:53:05
In message <>, David Maxwell writes:
>Even in my current mental state, that makes me very uncomfortable - rewriting
>the FS superblock and then hitting the power switch?

>Aren't you risking fs problems on your next boot there?

Risk is actually fairly small.  Figure:

1.  The system is in single-user mode, so nothing is actively writing.
2.  We have sync'd.
3.  We then write to the raw (uncached) disk device.
4.  After a short delay, when the disk light is done flashing, we depower the

Thanks to sync, everything ought to be in a stable state.  The change to the
superblock is trivial (one bit, I believe) and shouldn't affect any filesystem

FWIW, the system came up fine.  It fsck'd, but found nothing at all out of
order, not even the normal "BLK(S) MISSING IN BIT MAPS" stuff you get after
almost any unclean shutdown.

And now I have soft updates on /, without having to boot from floppy.  ;-)