Newbie Install Question - downloading and burning the install CDs, p2p

[Ari Torhamo]

ma, 2005-03-21 kello 21:49 -0600, Tommy Trussell kirjoitti:
> When you download an iso image, look in the same directory for
> md5sum.txt or filename.md5 files, and grab one of those, too. Then
> when your download is complete, you can have your machine check to
> make sure the file downloaded OK before you even try to burn it.
> 
> If the checksum file is "md5sum.txt" download it into the SAME
> directory as the .iso file(s) then type this command:
> 
> md5sum -c md5sum.txt
> 
> If the md5 file has more than one checksum in it but you didn't
> download all the files, it will complain about each missing file.
> HOWEVER if it does not complain at all about the file(s) you DID
> download, that means that file is OK. If you use the option -vc rather
> than just -c, it will print the file name and say "OK."
> 
> It's complicated to check the md5 checksum of an entire burned CD
> against the iso checksum. The Ubuntu CDs have a md5sum.txt file that
> lists all the package checksums, so from a working linux box you can
> check each of the files pretty easily.
> 
> I just popped an i386 Hoary Preview CD in this machine... this is a
> Debian ppc machine (slightly different OS, VERY different processor)
> but I can check the checksums of every package on the disk at a
> terminal prompt:
> 
> mount /cdrom/
> cd /cdrom/
> md5sum -c md5sum.txt
> 
> it's cranking through all the packages right now. The first try I used
> -vc so it was saying OK for everything. It's easier to just let it say
> whether it found a problem.
> 
> If this test identifies some bad md5sums, you might be able to install
> the rest of the packages on the CD, but since there are all sorts of
> reasons the files might not be readable you might want to toss that
> disk and check your burning procedures (try burning at a slower speed,
> see if you can tell the blanks were physically damaged, look for lint
> in the CD reader, etc.).


Thanks for the clear presentation about the subject - it was very
helpful for me. For the first time I managed to check the CD I burned -
and I have spent quite a few hours trying. I have an i386 PC and the
exact command that worked for me was 

md5sum -c /media/cdrom1/md5sum.txt

I did the check with the -cl option too to be sure that md5sum really is
doing it's thing :-)

I wish someone who knows more than I about different drive
configurations and other related things, would write an easy to
understand wiki guide about this. I would be happy to newbie proof
it :-)

Regards,

Ari