OpenBSD, Windows, and time zones

Time zones make dual-booting between OpenBSD and Windows a bit annoying. Windows saves the local time (including daylight savings changes, which is pretty bone-headed) to the hardware clock. OpenBSD, like most Unix systems, assumes the system clock is UTC and then adjusts for time zone, daylight savings, etc. One way to fix this problem would be to have both operating systems contact an NTP server at boot time and adjust the hardware clock to whatever they like. This seemed messy and Windows 2000 doesn't include an NTP client anyway.

It turns out OpenBSD's config(8) includes a timezone command to tell the OS that the hardware clock isn't set to UTC. I live in Pacific Time and daylight savings isn't active, so I had to tell the kernel that UTC is 7*60=420 minutes ahead of what the hardware clock says.

# config -e -f /bsd
OpenBSD 3.5 (GENERIC) #34: Mon Mar 29 12:24:55 MST 2004
    deraadt@i386.openbsd.org:/usr/src/sys/arch/i386/compile/GENERIC
Enter 'help' for information
ukc> timezone 420
timezone = 420, dst = 0
ukc> quit
Saving modified kernel.
# reboot

I suspect that I'll have to do that again when daylight savings kicks in.

Incidentally, GAG is still my favourite boot manager.

Posted by tim at September 25, 2004 11:54 AM