On Tue, 6 Jan 2015, Clem Cole wrote:
Also, for those of you that never saw Unix before fsck
or before the
work that Goble did at Purdue to get the write ordering down, you have
no idea what it was like to put a file system back together.
Somewhere, deep in Minnie's bowels, is the article I wrote, explaining
exactly how to use icheck/ncheck/dcheck/clri etc. I'm told it's saved the
bacon of quite a few people (assuming it was savable at all).
The sync;sync;sync stuff was because of the lack write
ordering; but
even with that, small file system corruptions where common.
It was drilled into us that the correct usage was:
# sync
# sync
# sync
This gives the disk buffers time to actually flush (the writes were merely
scheduled, and were asynchronous).
--
Dave Horsfall DTM (VK2KFU) "Bliss is a MacBook with a FreeBSD server."
http://www.horsfall.org/spam.html (and check the home page whilst you're there)