Path: utzoo!utgpu!water!watmath!uunet!cbmvax!ditto
From: ditto@cbmvax.UUCP (Michael "Ford" Ditto)
Newsgroups: unix-pc.bugs
Subject: Re: STIME April 20 on ps
Summary: Unix uses superblock update time until hardware clock is read.
Keywords: ps bootup time
Message-ID: <4786@cbmvax.UUCP>
Date: 21 Sep 88 06:29:03 GMT
References: <369@limbic.UUCP>
Reply-To: ditto@cbmvax.UUCP (Michael "Ford" Ditto)
Distribution: unix-pc
Organization: Commodore Technology, West Chester, PA
Lines: 23

In article <369@limbic.UUCP> gil@limbic.UUCP (Gil Kloepfer Jr.) writes:
>Has anyone else experienced this phenomena?

>							Could this be
>taking the time from a software R/T clock which hasn't been set yet until
>the hardware R/T clock is copied to the software one during some phase of
>the boot process?

When Unix boots, it uses the update time of the superblock of the root
filesystem to set its clock.  This is usually whatever time that disk
was last written to (usually just before the system went down).  On
the Unix PC the hardware time-of-day clock is set by /etc/rc, so any
processes created before that point will have incorrect STIMEs.  The
most annoying problem I have with this is that the boot time in /etc/utmp
is wrong, causing the "uptime" to be off by however long your system was
turned off.
-- 
					-=] Ford [=-

	.		.		(In Real Life: Mike Ditto)
.	    :	       ,		ford@kenobi.cts.com
This space under construction,		...!ucsd!elgar!ford
pardon our dust.			ditto@cbmvax.commodore.com