November 13, 2006

Verify your image files

Maybe you decided to test drive Linux by downloading and burning one of the Live CD distros, but were unable to get the CD to boot properly. There are several possibilities:

1) In your computer's BIOS, the ACPI could be on. Unless you're using multiple processors, it's probably a good idea to disable this feature. Unless, like me, your computer has this feature tied to another that I cannot do without

2) You burned the ISO image at too high a rate. I know that everyone loves to burn CDs at 48x or greater. Unfortunately, bootable OSs are a bit more sensitive to this. When I burned my first Knoppix distro, I threw away my first two burned discs because I had created them at too high of a speed. I tried it at 2x and the Live CD worked perfectly. Now when I burn an ISO, I typically choose the slowest speed possible.

3) The file integrity of the ISO is corrupt. Many of the Live CD distros are greater than 600 Mb. Larger files are more susceptible to getting disrupted while downloading. What you need to do is to verify the integrity of your ISO. Here's how:


The best way to check the integrity of your downloaded ISO file is with the md5sum checksum. The Linux distro download site should offer either a Web page display or a separately downloadable text file containing a string of checksum characters. This string has to exactly match the string you get when you run md5sum against your downloaded ISO file.

For Linux Users

The md5sum checksum functionality is built into Linux. To begin the process under Linux, change directories to the wherever you downloaded your .ISO file. Once there, open a "console" or "terminal" and type this command after the prompt and press Enter:

md5sum {DOWNLOADEDFILENAME}.iso

(Note: Replace the {} and what's inside them with the actual name of your downloaded .ISO file.)

Next, skip down to the "Analyze the Results" subhead and pick up the steps there

For Windows Users

To begin the process under Windows, download the Etre.org the md5sum.exe command-line utility or Luke Pascoe's md5summer Windows utility.

To use the DOS/Windows command-line utility, copy the md5sum.exe file to the proper directory:

For NT/2K/XP: Put md5sum.exe in {Your Windows Folder}\system32 folder

Then open a command prompt:

Windows 95/98/Me: Start > Run > command
Windows NT/2K/XP: Start > Run > cmd

Use the CD command to change directories to the wherever you downloaded your .ISO file. Once there, type this command and press Enter:

md5sum {DOWNLOADEDFILENAME}.iso

(Note: Replace the {} and what's inside them with the actual name of your downloaded .ISO file.)

The utility will create a checksum you can compare to the string offered by the Linux .ISO download site.

Analyzing the Results
Creating the checksum will take a few minutes. Once it's done, you can visually compare at least the first six characters and the last six characters of the two checksum strings. If they match, you're all set. It's time to burn your CD -- and that's the subject of our next tip.

There you have it. Now go have some fun.

Posted by: Physics Geek at 11:33 AM | No Comments | Add Comment
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