# md5sum random numbers?

## pstar

I think it is a hardware issue, but still don't have a clue about which part could be at fault.

Two Ubuntu install DVDs are md5 verified fine in my laptop but however generated random numbers (every time generated different md5sum) at

my Gentoo Desktop.

The Desktop have been overclocked before and tested working fine using Gentoo for about 1 years, compile Gnome and OpenOffice without issue. And

I have the BIOS setting back to pretty much default to preserve energy, now everything about CPU and RAM are using automatic detection settings.   

One thing I do suspect is that could be the RAM issue, as the Ubuntu DVD's I downloaded are Larger than other Linux ISOs I Downloaded so far, and I 

tried a few other ISOs (CD and DVDS in the same directory) and they all generated the correct md5 value except those two Ubuntu DVD's.

I am using gentoo kernel 2.6.32-r7 32 bit with PAE on 4G RAM. As there are lots of information could be related to my problem, I will supply more information

on request or I see related later.

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## pstar

Strange thing is sha1sums will give me correct hash code.

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## Akkara

Try putting the clocks back to normal and try the md5sums again.  I've never consistently gotten a machine to overclock much more than 5-10% above spec, and the failures are often subtle like this.  It might seem like it's working most of the time but there's always 1 or 2 programs that stresses it in a way to make it fail.

I've also seen this happen with iffy memory.  You might want to try re-seating the modules.  If it still gives you different md5's, try removing half the modules, and then the other half.

In any case, this is telling you that something's wrong.  Try to find out what it is.  Don't put it aside, because it will return to bite you in different and less-easy-to-see ways in the future.  Such as filesystem corruption and the like.

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## frostschutz

You could also use dd to pull two .isos of the same DVD, then use byte-wise comparison of the two .isos... that way instead of a random hash, you will see exactly where the differences be. Could be a faulty drive that sometimes does not read the correct data.

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## pstar

 *Akkara wrote:*   

> Try putting the clocks back to normal and try the md5sums again.  I've never consistently gotten a machine to overclock much more than 5-10% above spec, and the failures are often subtle like this.  It might seem like it's working most of the time but there's always 1 or 2 programs that stresses it in a way to make it fail.
> 
> I've also seen this happen with iffy memory.  You might want to try re-seating the modules.  If it still gives you different md5's, try removing half the modules, and then the other half.
> 
> In any case, this is telling you that something's wrong.  Try to find out what it is.  Don't put it aside, because it will return to bite you in different and less-easy-to-see ways in the future.  Such as filesystem corruption and the like.

 

Thank you, will try the memory first. But the thing is the everything is on the right clock already for a few months now.

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## pstar

 *frostschutz wrote:*   

> You could also use dd to pull two .isos of the same DVD, then use byte-wise comparison of the two .isos... that way instead of a random hash, you will see exactly where the differences be. Could be a faulty drive that sometimes does not read the correct data.

 

Will try dd as well, so I can get a affirmative that my hardware are going south rather not md5sum alone. As I tried K3b yesterday, it will give my correct md5 every time. But if I use md5sum in terminal, I always get different hash code, and some time I will get correct one, like one fifth of chance md5sum will get it right...

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