I'm not sure if this is the right forum to ask this question, as I believe my problem to be hardware related, but here goes:
I recently bought a new desktop computer (because my girlfriend had all but taken over my old one :-) )
Here are the specs:
AMD Athlon 64 X2 Dual Core Processor 6000+
Abit motherboard A-N68SV(MCP68S)
4GB DDR2 RAM
500GB MAXTOR STM350032 harddisk
Realtek RTL8101E/RTL8102E PCI Express Fast Ethernet controller
nVidia GeForce 7025
I had a hard time installing an OS. First I tried installing different versions of Windows, but the installation went wrong every time - I can't remember the exact error message, but I think it said the install CDs were bad (they worked ok before and have worked fine after on other systems).
Then I tried Ubuntu Intrepid, and after a couple of tries I finally had a running system.
However, once in a while when I installed or updated applications, the installation would fail or the application would just not work. After much detective work I finally realised that the downloaded .deb packages were corrupt! Here is an example (the wine-gecko package), first lines are from the healthy file, second from the corrupt:
< 00005240 f6 c1 fb b7 4d 3c bb 03 f3 13 4d be 3a b6 0b 9a
> 00005240 f6 c1 7b b7 4d 3c bb 03 f3 13 4d be 3a b6 0b 9a
< 0000d020 ca 02 8b 27 a4 b7 bd 7b 5d 20 44 dd f8 b9 36 54
> 0000d020 ca 02 0b 27 a4 b7 bd 7b 5d 20 44 dd f8 b9 36 54
< 002785e0 1b 4c 84 cd cd 62 5a 39 c9 cd de ca d5 e5 30 9b
> 002785e0 1b 4c 04 cd cd 62 5a 39 c9 cd de ca d5 e5 30 9b
< 0050f360 54 69 f9 0e 0b 45 22 0d 7e bd 3f 25 7c 4d 52 ff
> 0050f360 54 69 79 0e 0b 45 22 0d 7e bd 3f 25 7c 4d 52 ff
< 00557ae0 ae de b5 3d b6 d3 bb e9 95 5e c4 b6 f3 dc 60 c9
> 00557ae0 ae de 35 3d b6 d3 bb e9 95 5e c4 b6 f3 dc 60 c9
Notice how the error is always a 1-bit switched to a 0, and always in the same position modulo 32 bytes!
My first thought was that the package was corrupt in the repository, but after downloading the same file a couple of times with errors appearing in different places each time (but still the same bit modulo 32 bytes!), that was obviously not the case.
My next thought was a faulty harddisk, so I tried downloading to a usb stick instead - still with the same problem.
Then I tried running memtest86+, and it showed a bunch of errors, so I thought that I had found the problem, but no, after replacing the faulty ram stick, I still had the same problem.
I *do* blame the ram errors for my problems with installing an OS in the first place though.
It should be noted that the problem usually does not show up immediately after a reboot. If I notice that a downloaded package is corrupt, I just reboot the system and download again. Then the problem usually goes away for a couple of hours. This does sound a bit like some hardware part getting too hot - but if so, why would the problem go away for several hours after a reboot? It's not like the computer would cool down much during the 30 seconds it takes to reboot?
Next up for scrutiny: The network card. Now, if the network card was faulty, wouldn't the network driver notice errors in the TCP/IP packet checksums? Or are the checksums performed on the card itself? I do have a spare network card that I can try instead, it just does not seem (to me) a likely source of the problem, so I have not gotten around to try it yet.
I will be very grateful, if anyone can suggest what else I could try - I'm still hoping I won't have to replace the motherboard.
As a side note, I find it strange that some applications were installed without apparant errors, even though I could see that the package was corrupt! For example the wine-gecko_0.1.0-0ubuntu1_all.deb package; when I installed the package (from Synaptic Package Manager), no error was shown in the log, but when I unpacked the file, the contained data.tar.gz archive was corrupt.