I am not really sure where to start but I suspect that I have a hardware problem with one of my boxes.

My laptop can transfer files to a usb drive which then can be loaded and installed on other systems. My second, older, "test" box can also transfer files to both the usbpen drive and can burn the files to a cd which then install correctly. If I download a file to my third, newest system the files (slackware *.tgz packages) install fine on the new box but when I try to transport those files to my laptop or the "test" box they do not install and give the error message that the files are corrupt. This is particulary evident with files larger than 4-5mb. Small files ~0.5mb seem less likely to become corrupted with transfer or burning.

I have a Gigabyte GA7-VTXH mobo, Athlon 1600XP, 256mb PC2100 ECC CAS 2 ram x 2 and a WD 7200 8mb cache 80gb HD.
I have set the CAS latency up in the BIOS from 2 -> 2.5 and have run memtest which shows no errors. I also have to repair my file system frequently (all files *ext3) with e2fsck.

I also changed out the cpu which did not fix the problem.

Any help appreciated.

Suppose you've tried swapping out the harddrive (install minimal slack on a old / known good drive, then try writing a large file to the usb drive)?

Are your machines networked / networkable? What happens if you transfer files over the LAN from newest box to laptop / test box?

Statistically, I'd say "hard drive", but I assume it's a new one if you kept your old box?

Yes, the new box has new WD hard drive. I had an IBM hard drive but It quit working altogether so I threw it out. I do not have a hard drive around to put a minimal slack install on but I have seen no messages regarding bad sectors etc.

I have a mini network (just the new box on a cisco dsl modem acting as a firewall.).

Oddly enough when I download an application to the hard drive of the new box it is intact and usable. It is only when I try to transfer the file from the harddrive to the usbpen drive or burn the file to a cd.

As I said the hard drive is relatively new but is there a way I can test the hard drive in linux? Last I looked Western Digital only had windoz based hard drive testing programs.

I just googled and found that Hitachi/IBM has a linux hard -drive interegator. It will work on other brands of drive but will do some additional things with Hitachi/IBM drives. My Western Digital did not have any errors..

In the future when I choose another HD IBM will get some points. I could not find any linux support on the WD support page.

Also read the man page for hdparm -v here is my output

multcount = 16 (on)
IO_support = 1 (32-bit)
unmaskirq = 1 (on)
using_dma = 1 (on)
keepsettings = 0 (off)
readonly = 0 (off)
readahead = 8 (on)
geometry = 9729/255/63, sectors = 156301488, start = 0

Since both the CD burner and USB pen drive use SCSI emulation could this be a problem? One thing that suggests it may not be a SCSI problem is that I cannot copy (cp) large files to my /burnbuffer for XCDroast but can move (mv) them without a problem.

I think I may have fixed it. I selected optimized defaults in the bios and it disable s.m.a.r.t for hard drives. After doing that I was able to copy openoffice to the pen drive and cleanly extract it on a second computer. If anyone knows anything about s.m.a.r.t for hard drives I would not mind learning.