DST adjustment changes clock by TWO hours from saved disk ..

[Guest]

Archived from groups: microsoft.public.windowsnt.misc (More info?)

I have a weird problem that I'm looking to explain.

I have a PC that is running fine and has the correct date and time both in
Windows NT and in the BIOS, so they match. I also read the values in the
Real-Time Clock Chip, and the DM bit in register 0x0B (which tells the RTC
whether to do automatic DST) is disabled, which is the way that one would
expect Windows to set it.

I have a disk image that I made of my system back in August (before the
Daylight Savings Time switch at the end of October), and the "automatic DST"
check box is checked.

I then copy the disk image to the hard drive of the PC. However, when I
boot up the machine, it ends up setting the clock back TWO hours. One hour
is easy to explain because from the point of view of the OS, the last time
the machine booted, it was August, and it's now December, so it needs to set
the clock back by one hour for automatic DST. But what it setting it back
another hour?

I corrected the time, and set the date for the last Sunday in October, and
let it hit 2 AM naturally, and it did the right thing and only set the time
back one hour. So, that works fine.

I then copied the image to a different PC with a different type of
motherboard (Intel versus Portwell) and BIOS (Award versus Phoenix), and got
the same result of TWO hours.

I then copied the image a second time onto the same PC, and it again sets it
back another 2 hours (thus, it's now 4 hours behind), thus showing that
whatever state is being messed with is not in the BIOS nor hardware.

Can anyone explain how/why it's being set back two hours instead of just
one?

(Thanks in advance.)

 

[Guest]

Archived from groups: microsoft.public.windowsnt.misc (More info?)

different time zones

 

[Guest]

Archived from groups: microsoft.public.windowsnt.misc (More info?)

"dlw" <dlw@discussions.microsoft.com> wrote in message
news:EDBD3772-3CA5-4AC3-984C-D05A22B11A45@microsoft.com...
> different time zones

Nope, that's not it.

For one, I said that I did this test (which would not have different time
zones since it's the same image):
> I then copied the image a second time onto the same PC, and it again sets
it
> back another 2 hours (thus, it's now 4 hours behind), thus showing that
> whatever state is being messed with is not in the BIOS nor hardware.

Plus, how would it know that it had different time zones? It has no way of
knowing what the previous time zone would be since time zone information is
only in the OS (which is overwritten); it is not saved in the BIOS nor
Real-Time Clock chip.