system time changes whenever I reboot the sled 10 box

[needee]

plz help
system time changes whenever I reboot the sled 10 box. This box is a dual-boot with SLES 10, and system time doesnt change, when I use SLES 10.

[gogalthorp]

GO to Yast-System-Date TIme

Change the Hardware clock setting. If UTC change to local if local change to UTC

[needee]

Thanks Dear gogalthorp for help.
I followed your instruction and it works fine ... thanks once again.
I changed the clock from Local to UTC.

But why... I mean whats the reason/cause of time change.... because dear gogalthorp, I think that your instruction is simply a workaround to handle an issue/bug/error.... its not the proper solution/remedy(this is what i think.... and I am simply a newbie )

I wana know the actual issue ... or simply why time changes when system clock was set to "Local time"

Plz help
Regards
Needee

[gogalthorp]

All the OS's must use the same base time which is supplied your hardware clock. If you go into RH you will probably see that it is set to assume the hardware clock is UTC. THat is why there was a difference.So if you go into your BIOS and look at the time it should give the time as UTC not local time. UTC is also known as Greenwich Mean Time

see
http://aa.usno.navy.mil/faq/docs/UT.html

[needee]

I agree with u dear, you provide the technical reason.. I appreciate... but I still i am not satisfied ;(
the reason that I am not satisfied is that ... this same machine(hardware/BIOS), is a dual boot machine(SLES 10/SLED 10)... and only SLED changes the time... not the SLES, even in sles the system time is set to LOCAL time.

Anyway millions of thanks for the support
Regards
Needee

[Technarazzi]

OK, here's how real operating systems keep time:

The hardware clock has a number. That number is the number of seconds since 12:00AM January 1st, 1970, UTC- which is pretty much GMT. Like, in London, on that date, at that time, that was the beginning of time for UNIX; it was zero, see? In a perfect world, every UNIX computer in the whole world would have exactly the same number in its hardware clock all the time. UNIX time is UTC- it's the same everywhere. Makes keeping them all set to the correct time lots easier, see? They all send one single number to each other. That's all they need, no conversions, no fooling around- that number is the same in Delhi as it is in Zurich.

OK, so you're a human. You want Mean Solar Time for the timezone you're in. Great, listen, it's a computer, all you gotta do is a quick little calculation, they're made to do that. All it needs is a little piece of data that tells it what timezone you're (or it's) in, take that number out of the hardware clock, run it through an algorithm with that piece of data, badda boom badda bing, there's your mean solar time.

So you gotta do two things:
1. You gotta make sure the computer knows what time it is. Look into ntp. Most distros come with xntpd; SuSE does, all the way back to, I dunno, 6.x or 7.x? I think I got 6.3 and it didn't have it, I hadda download it and build it, hey man, that was in, like, the Stone Age, you know? Configure it in YaST; Network Services->NTP Configuration will get you there. If you have a local time server, use it; if not, then check the Use Random Servers from pool.ntp.org checkbox and get DSL or a Cable modem. Come back and ask questions if you can't figure it out. We'll fix you up, and you'll learn some Linux. Worse come to worst, just hard set it using the menu below; but don't forget to also visit the menu below and set the timezone.
2. You gotta make sure the computer knows what timezone you're in. YaST oughtta take care a that for you, an there ain't no complications to it; System->Date and Time will do it. Get in there and fix it up.