Use md5sum to verify that your ISO downloads are good

Subject:        Re: 7.2 won't install from ISO
Date:           Mon, 06 Nov 2000 04:27:29 GMT
Newsgroups:     alt.os.linux.mandrake

Sleepy wrote:
> I just burned the Mandrake 7.2 ISO install and ext CD's.  When I boot off of
> the install CD I get past the first screen where you are asked if you want
> to install or upgrade.  Then as the cd-rom intializes it waits a while and
> then says there doesn't seem to be Linux-Mandrake on the CD.  I burned a
> second copy from the ISO.  Same thing.  I have a feeling I'm not the first
> person this has happened to.  If I need to do something to the ISO before I
> burn please tell me.  Any help would be greatly appreciated.  Thanks
> Sleepy

If you got as far as being able to run the install program, then you probably burned it OK, but you haven't determined that the ISO image file you downloaded is good. FTP is imperfect, unfortunatly.

Use a md5sum program to check to make sure that the ISO image file you downloaded is good. md5sum is already on Linux. A DOS md5sum program is available at

The general idea is to run the md5sum program and give it the name of the ISO file. Then compare the string of numbers and letters it prints with what is in the md5sums file you download from the same place you got the ISO images. The md5sums file is tiny--it is only a two line ASCII text file that contains the name of the ISO files and the md5sums that were calculated on their machine (i.e., before being downloaded.)

Be prepared to wait a few minutes, because it takes a while to calculate the md5sums from something as large as an ISO image file.

I was able to install Mdk 7.2 from CDs I burned from ISO image files I downloaded. But I first checked them with my md5sum program before I burned them. Example. I downloaded my Mandrake 7.2 ISO images on my Mandrake 7.1 machine with gFTP and put them in a /downloads/Mandrake7.2 directory. I also downloaded the md5sums file.

ls -l
total 1230144
-rw-r--r--    1 user     user     579280896 Oct 27 14:50 Mandrake72-ext.iso
-rw-------    1 user     user     680378368 Nov  2 07:53 Mandrake72-inst.iso
-rw-r--r--    1 user     user         1398 Oct 25 16:01 README
-rw-r--r--    1 user     user          107 Oct 27 14:53 md5sums

I then listed the contents of the md5sums file. This contains the md5sums that were calculated by whoever originally prepared the ISO image files.

cat md5sums
ffcd786f04c76d193379eed4670ecfde  Mandrake72-inst.iso
e258584f8ebcf1d5d16ad63a51eb9321  Mandrake72-ext.iso

Now it is time to calculate the md5sums of the ISO images I just downloaded.

md5sum -b *.iso
e258584f8ebcf1d5d16ad63a51eb9321 *Mandrake72-ext.iso
ffcd786f04c76d193379eed4670ecfde *Mandrake72-inst.iso

Because the md5sums are identical, I know that my ISO files downloaded OK and I can burn them to a CD. Check man md5sums for more information.

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