Checking the integrity of a Live CD

From MEPIS Documentation Wiki

Revision as of 14:33, 15 March 2009 by Marvin02 (Talk | contribs)
Jump to: navigation, search

Contents

Verify CD

Cdrom unmount.png

When burning a CD with K3b make sure you compare the MD5 sum calculated by K3b with the one in the downloaded .md5sum file. Don't forget to select the verify written data checkbox if you want K3b to check if the CD was burnt correctly.

After burning a Live CD, you may want to verify the integrity of the CD. Here's how you can do that:

On Linux

In terminal type:

 md5sum /dev/cdrom

Depending on your system you might need to replace cdrom with cdrom1 or another device name like hdc (/dev/cdrom is the first CD drive, /dev/cdrom1 is the second one, etc.)

Wait for 2 to 5 minutes, depending on your CDROM speed, for your CD to be read and MD5 sum to be calculated, compare the MD5 sum obtained with the one that you got from the download site, they should be the same.

(This test fails for CD recorded 'track at once'. Use 'session at once' mode. When using cdrecord, use -dao switch.)

Iso-md5sum.png

You can use this verify method for CDs burned with any software, not just K3B.

K3B Verify Errors

If K3B reports a verify error you should check the md5sum from the command line as described above. There have been reports of K3b erroneously reporting a failed verify after burning. Mepis Forum topics:

Anyone blaming burn issues on K3B this beta-cycle?

K3b showing erroneous mismatch errors on burning

Finding your device name

With a CD or DVD in the device right click on the icon on the desktop and select properties from the menu that pops up.

Device-name.png

On Windows

  1. Get the free version of the Windows application IsoBuster, available at isobuster.com.
  2. Insert CD in drive.
  3. Run IsoBuster as Administrator.
  4. In registration dialog, select "Free funct. only".
  5. In left pane, right-click on CD (top line) to get context menu, and select: "MD5 Checksum file" >> "Create MD5 Checksum" >> "For image file with 2048 bytes/block".
  6. Compare the MD5 in the .tao line of the output with the MD5 in the downloaded .md5sum file.

Alternate method of checking CD: Use IsoBuster to create an .iso file from the CD, and then do a binary comparison of that file with the downloaded .iso (using fc /b from a command prompt); the files should be identical.


Back to installation guide | Main Page

Personal tools
In other languages