MD5 and SHA1SUM Problem
 

My desktop is currently dual-booted running Suse 9.3 and Kubuntu 5.04. I have two hard drives attatched to seperate ide controllers, and a dvd drive. Anytime I try to calculate an md5sum or sha1sum on files over aprox. 100mb they come up incorrect (occasionally smaller files will come up incorrect too). (if I run md5 or sha1 on the same file multiple times will give a different value each time.) This is true for all three partitions (all formatted with reiser.) and the cdrom drive (I tried to verify the md5sums for the packages in doom3). I downloaded a couple ISOs from damnSmallLinux and the mdsums came up correct, but all those files where 50mb or less. I have tried reformating but the results are the same in both OSs. I downloaded Fedora 4 on my laptop and verified the SHA1SUMs and tried to install it on the desktop and got a crc error the first time then each time after start to load but it would go to a kernel panic (Also with both Fedora and Kubuntu when I put it the install cd the logo picture doesn't show up instead its just a big white box). (The install CD loaded fine on the laptop.) I am at a complete loss so any help at all would be greatly appreciated.


Setup (in case it helps)
3.2 ghz Pentium with HT
INTEL 915P Chipset
NVIDIA Geforce 4000mx
1Gb RAM
Western Digital 80 gb HD
Seagate 160 gb HD
Pioneer DVD-RW DVD-105
Kernel 2.6.11-smp
kde 3.4.1

Could it be that your hardware is broken? Try downloading a large file, copying it several times on the hard drive, and doing 'diff file1 file2'. CRC error sounds like broken hardware...

I download the iso for kubuntu and copied it 4 times and compared the first to the last with diff and it told me the files were identical. I then ran md5sum on both files and they came up different still. I was concerned that this might be a hardware problem but if so do you have any idea what it would be. It seems weird to me that both hard drives and the cd drive would stop working at the same time. (One hard drive and the cdrom drive are connected to the one ide controller on the motherboard, the other hard drive is hooked up to a pci ide controller.) Up until tonight everything else seemed to be running fine in Suse, but now open office calc stopped working (writer and impress still work). I've searched through the lod files and found a few drive seek complete errors from a few days ago but that was it. Any thoughts?

To me this sounds like a kernel(driver) or hardware compatibility problem. This may be a dumb question, but why are you using an SMP kernel when you only have one processor? (SMP = Symmetric Multi-Processor.)

Simon

The smp kernel is also used for hyper-threading support, but good point. That got me thinking and I switched to the default kernel and disabled hyper-threading in BIOS, but I'm still getting the same results.

Have you tried strace? I installed strace from FC4 DVD and tried something like strace md5sum somefile. I don't know exactly what to look for in the output but if there's some errors in system calls you should be able to spot them.

How well have you checked that your hardware is compatible with Linux (and the distros)?

I ran strace and it didn't show any errors. I copied the file to another computer through nfs and the md5sum showed up correct on the other computer so i know the data isn't getting corrupted. As far as I know all of the hardware is supported Suse detected and allowed me to configure all of it without any problems.

Well not everything that gets detected is guaranteed to work perfectly.

I guess md5 and sha1 need a lot of computing power on big files and put the processor under heavy stress. This causes considerable heat, in the summer particularly. Overheating is known to cause calculating errors sometimes. How's your computer's ventilation and cooling system doing?

Intel has some Linux information also. Take a look at this for example. Some BIOS tuning might help. Then again, it might not.

Well I finnally gave in and got the hardware tested and apparently the pci card that my one hard drive was hooked up to was a piece of shit and it ruined that hard drive. Thank you everybody for your help though.