Subject: Re: clock problem ...
To: Andrew Todorov <>
From: Jonathan Stone <jonathan@DSG.Stanford.EDU>
List: tech-kern
Date: 01/25/2000 15:14:08
In message <000f01bf677f$4fb47fc0$02e1a8c0@andrew>,
"Andrew Todorov" writes:

>How can I setup my NetBSD clock to be equal to BIOS clock ?
>Thank's for help!!!

NetBSD already gives you a NetBSD clock that's taken from the BIOS
clock,  Unless you've done something special to disable that.
(I'm ignoring some subtleties like checking root filesystem dates here).

What's probably happening is that some mis-designed OS is trying to
run your BIOS clock in local time.  This never works, and can never
work, due to daylight-savings: the rules change, and OSes are not good
at keeping up with it.  The best answer, the only good answer,
is to run your clock in UTC or GMT or some standard time, and let
userlevel code  figure out what the UTC-to-local correction is.

The best solution for that, is to not use the misdesigned OS, and
reeset your BIOS clock to UTC.  Since Windows suffers from this flaw,
that's a very hard pill for some users.

The best you can do is to use the RTC_OFFSET option in your kernel
config file. That gives NetBSD a constant offset which it folds into
the BIOS clock before computing the `real' time.  That sort-of works,
but if you dual-boot Windows, you need to change RTC_OFFSET when
daylight savings changes. IIRC< Pery Metzger used to build two kernels
with RTC_OFFSET values an hour apart, one for daylights savings, one

PS: I think you'd make the list happier, and maybe even get
more/better answers, if you stopped posting HTML...