Subject: kern/9549: RTC_OFFSET has DST problems
To: None <>
From: John Hawkinson <>
List: netbsd-bugs
Date: 03/05/2000 15:03:36
>Number:         9549
>Category:       kern
>Synopsis:       RTC_OFFSET has DST problems
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    kern-bug-people (Kernel Bug People)
>State:          open
>Class:          doc-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Mar  5 15:03:00 2000
>Originator:     John Hawkinson
>Release:        NetBSD 1.4.1
System: NetBSD 1.4.1 NetBSD 1.4.1 (ZORKMID) #9: Sun Mar 5 15:44:11 EST 2000 i386

	This text hasn't changed in -current.

	options(4) fails to note that using RTC_OFFSET to allow
	multiple OSes to coexist with the hardware clock in
	local time has serious DST-flaws.

	It'd be nice if there was an innovative way to address those
	DST problems, but all the solutions I can think of seem
	to fall under Way Too Ugly (tm).


RCS file: share/man/man4/RCS/options.4,v
retrieving revision 1.1
retrieving revision 1.2
diff -c -r1.1 -r1.2
*** share/man/man4/options.4	2000/03/05 22:46:58	1.1
--- share/man/man4/options.4	2000/03/05 22:56:56	1.2
*** 785,790 ****
--- 785,800 ----
  in system initialization scripts.
  Changing this value currently may only be done at kernel compile
  time or by patching the kernel and rebooting).
+ .Pp
+ .Em NOTE :
+ Unfortunately, in many cases where the hardware clock
+ is kept in local time, it is adjusted for Daylight Savings
+ Time; this means that attempting to use
+ to let NetBSD coexist with such an operating system, like Windows,
+ would necessitate changing
+ twice a year. As such, this solution is imperfect.
  .It Cd options KMEMSTATS
  The kernel memory allocator,
  .Xr malloc 9 ,