File corruption

[snarks]

When I copy a large file, the copy of the file is not identical to the
original. On a 1GB file, there are typically about a dozen bytes that
all have an additional bit set, here is the result of the FC /B
command:

Comparing files file1 and file2
04393D55: 20 60
045D7755: 02 42
05E6A955: 09 49
079CC155: 2D 6D
0BC85155: 27 67
0C0FB355: 0C 4C
15252F55: 13 53
1979CB55: 02 42
1AE7F955: 00 40
1B60C555: 00 40
1FED4D55: 10 50
26D05355: 1E 5E
2A9B7155: 01 41
2FF13755: 1A 5A
34431F55: 25 65
355B6F55: 03 43
3A1A5355: 14 54
3BA12555: 0C 4C
3BA80D55: A8 E8

Note that the offsets all end in 55, and the bytes have ll been ORed
with hex 40.

I have checked for disk errors, viruses, rootkits, and spyware using
CHKDSK /F, Avast!, RootkitRevealer, and AdAware.

The error only appears on large files, and also appears when copying a
270MB file to a USB memory device.

Any suggestions? I suspect a faulty RAM.

Phil Hibbs.

 

[Bob Willard]

When I copy a large file, the copy of the file is not identical to the
original. On a 1GB file, there are typically about a dozen bytes that
all have an additional bit set, here is the result of the FC /B
command:

Comparing files file1 and file2
04393D55: 20 60
045D7755: 02 42
05E6A955: 09 49
079CC155: 2D 6D
0BC85155: 27 67
0C0FB355: 0C 4C
15252F55: 13 53
1979CB55: 02 42
1AE7F955: 00 40
1B60C555: 00 40
1FED4D55: 10 50
26D05355: 1E 5E
2A9B7155: 01 41
2FF13755: 1A 5A
34431F55: 25 65
355B6F55: 03 43
3A1A5355: 14 54
3BA12555: 0C 4C
3BA80D55: A8 E8

Note that the offsets all end in 55, and the bytes have ll been ORed
with hex 40.

I have checked for disk errors, viruses, rootkits, and spyware using
CHKDSK /F, Avast!, RootkitRevealer, and AdAware.

The error only appears on large files, and also appears when copying a
270MB file to a USB memory device.

Any suggestions? I suspect a faulty RAM.

Phil Hibbs.

Sure sounds like a hardware problem, and RAM is a good bet. Download
MEMTEST86 and let it run overnight.

 

[snarks]

I downloaded that the other day, but I need to go to a museum and
borrow a floppy disk to boot from.

Phil Hibbs.

 

[Malke]

I downloaded that the other day, but I need to go to a museum and
borrow a floppy disk to boot from.

Phil Hibbs.

You don't need a floppy to use Memtest86+. You can download an .iso to
create a bootable cd. You'll need third-party burning software, though.
XP's built-in burning capability won't work with the .iso.

Get Memtest86+ (the updated version of Memtest86 taken over from the
original author who is no longer active on this project) from
www.memtest.org .

Malke

 

[snarks]

Ah, splendid. Unfortunately I don't have any blank CDs to hand either
(loads of DVDs though).

Phil Hibbs.

 

[snarks]

OK I tried Memtest86+ but it didn't find any fault. I have returned the
machine to the manufacturer for diagnosis and repair.

 

[snarks]

The fault seems to have been caused by one (or a combination) of 8
viruses that I had on my machine. So much for Avast! antivirus.

 

[Bob I]

Yes, the definitions to identify the intruder must be in place to stop them.

 

[snarks]

Well, it turns out that it wasn't the viruses at all. Even after
re-formatting the partition and re-installing Windows XP, the file
corruption still occurs on the C: drive, but not on the shiny new 80GB
D: drive.

Phil Hibbs.