VirtualLarry, pcgeek,
Thank you for the responses, I did not think it was the CMOS battery! Concurrently with the 2 hours that have lapsed since my response here I did some more troubleshooting of the issue.
I did so using my dual boot setup (grub on a Linux partition on HardDriveA, Windows XP booting on HardDriveB) plus a LiveUSB Ubuntu 11.04.
I'll be using the term "localtime" to denote my Pacific timezone.
1) Booting into Windows and restarting into BIOS, time did not change in OS (both were localtime) and BIOS.
2) Booting into the LiveUSB Ubuntu 11.04 would result in the OS changing the time to be UTC; however, on restart the BIOS would still be in my localtime).
3) Booting into HardDriveA Ubuntu 11.04 would result in OS showing localtime; however, on restart the BIOS would be set to UTC!
It is a bit disconcerting to me that Ubuntu would access and change the BIOS without warning... it appears that this is not done during start-up, but during shut-down.
I used Google and first came upon
this thread (via ubuntuforums.org). Quoting the response:
Hello.
On a normal install I have to edit "/etc/default/rcS" and change the utc line to " UTC=no".
Save and next time you boot it will use local time. If your install is persistent this should work. I hope this helps.
A.
I think came upon further information at
this thread (via help.ubuntu.com). The introduction (click through if you are interested in how to "fix" Windows rather than Ubuntu):
"Multiple Boot Systems Time Conflicts":
Operating systems store and retrieve the time in the hardware clock located on your motherboard so that it can keep track of the time even when the system does not have power. Most operating systems (Linux/Unix/Mac) store the time on the hardware clock as UTC by default, though some systems (notably Microsoft Windows) store the time on the hardware clock as the 'local' time. This causes problems in a dual boot system if both systems view the hardware clock differently.
I made the change to the HardDriveA Ubuntu 11.04 install and it worked. It's no longer changing the hardware BIOS setting. It appears this is done on shutdown, rather than start-up (wonder what happens if the BIOS password is set, unlike my insecure system?). Strangely enough I couldn't change my LiveUSB (maybe its not persistent), so I guess that OS will need to be adjusted whenever I use it. But it was not writing anything to the BIOS upon shutdown.
I hope someone using Google or another search engine trying to wonder what's going on finds this thread useful. Google took me on a strange route to get to the first link; and then having found it I was able to search for "/etc/default/rcS" to get to the other link.
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