k3b verify error

[amenditman]

First,

Hello to Fedora Forums, my first time here.

I burned the Fedora 10 KDE x86_64 iso with K3b.
The last step is to verify the written data, I get errors.

I tried download again from different mirror and burn that, same result.

I have had this problem with other distros iso's and can't figure it out.

What do you think?

amenditman

[stoat]

Hello amenditman,

Well first of all, once you have verified the SHA-1 hash of a downloaded Fedora ISO file (and you should always do that (http://forums.fedoraforum.org/showthread.php?t=166240)), you never have to download it again. It's good. Period. When k3b verifies the data it burns to a disk, it is comparing the data on the disk to the file it started with. It doesn't matter whether the data in the file it started with is good or bad. K3b would not know that. So if this were happening to me, I would suspect either my burner or the disks I was using. In my experience, I've had both go bad or be bad.

I did a quick (but not thorough) search for K3b problems related to verifying burned data. My quick look didn't plow up anything. That would be easy to check anyway by burning with some other software (e.g., Nautilus, gnomebaker, Nero, etc.). It's also possible to run sha1sum on the final disk and generate a hash to compare to the hash in the file SHA1SUM that accompanies Fedora ISO files. It requires a simple script to remove the so-called "padding" added by the burning software. It's not hard to do, but it does require a little effort. The result is a hash that will perfectly match the original hash of the ISO file if nothing is wrong with the data on the disk. I don't routinely do this, but it can come in handy somtimes. In case this mystery leads you to want to do that, you can learn about it in another thread here (http://forums.fedoraforum.org/showthread.php?t=166240).

Can you try ruling out (or in) the burner by creating the CD on another computer? I've had those things suddenly go over a cliff.

Can you try another (perhaps better) brand of CD? They're not all the same. I have far more issues like that with DVDs than with CDs, but it still applies. The optical quality of the final disk varies greatly from brand to brand. It can be demonstrated (http://forums.fedoraforum.org/showthread.php?t=189020) with a free utility such a Nero DiskSpeed which scans a disk evaluating its quality. Even when the data burned into the disk is perfect, that no longer matters if the reading drive cannot read it (even if its the same drive that just burned it).

In the end, I don't have any way of knowing what's the matter. These where just my thoughts about it.

[amenditman]

Thanks stoat!

I will check out the SHA 1 SUM suggestion.

As to the other possibilities, I can't really tell.

I burned a total of 8 iso's to disc today, 2 of them failed the verification. They were not the last two or even two in a row.
I used two different types of CD's and the failures were split up. The CD's are HP and TDK branded and I'm over half way thru the stack of 100 in each, no previous problems.

The iso's which failed were both of linux distros and were both for 64 bit systems.

Not much to go on if it's not the file being corrupt.

Thanks for thinking about it.

Blessings
amenditman