1. Check Your Linux 'ISO'
Welcome to a new, recurring section of Scot's Newsletter called Tips for Linux Explorers. It's become clear to me that a growing percentage of Windows users (including me) are interested in at least dabbling with Linux. You may not be ready to chuck Windows just yet, but it can't hurt to educate yourself either.

Tips for Linux Explorers is aimed at Windows users who would like help figuring out how to download, install, configure, and use Linux. The plan is to offer a new installment of this series in every issue of Scot's Newsletter.

Most of the material you'll read in this section comes from Bruno of Amsterdam, one of the moderators of the All Things Linux forum at Scot's Newsletter Forums. Bruno is helped by All Things Linux co-moderators Peachy and ThunderRiver, as well as other forum members who have posted in the highly useful Tips for Linux Starters thread.

Bruno, who modestly describes himself as "only a normal Linux-user giving tips to other Linux-users," envisions over 60 installments of the Tips for Linux Explorers series. He's already published many of them in the Tips for Linux Starters thread. Bruno, Peachy, and ThunderRiver have also helped several SFNL Forums members successfully install Linux on their computers. And they go about it in a friendly, non-judgmental way. So, if you like the first tip in the series, check out the rest.

Checksumming A Downloaded Distro
So, you want to try Linux? If you don't opt to purchase Linux from one of the operating system's major suppliers, your other option is to download a free copy from the Internet. Generally speaking, Linux distros (Linux distributions or versions) are tens of megabytes in size. So you need a fast broadband connection or the ability to tie up your dial-up connection for hours and hours. Two top resources for finding Linux distro download links and learning more about them are LinuxISO.org and DistroWatch.

Downloaded distros have the .ISO filename extension, which is why they're commonly called ISOs. For a quick definition of an ISO, see LinuxISO.org's What is a Linux ISO?. For more details on ISOs and how they differ from other downloads, see this SysLinux by Peter Anvin FAQ about ISOLinux.

A future installment of Tips for Linux Explorers will cover working with the download to install it. But your first step after downloading an ISO is to check its file integrity. A large file is more susceptible to corruption during download than a smaller one, and many a Linux installation has been stymied by a corrupt ISO. So don't blow this off as a problem that couldn't happen to you. Do it before you burn your ISO to a CD.

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:


(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:


(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.

If you're a dial-up user or just don't want to put up with managing and .ISO file, you can buy most Linux distros from their distributors, or try CheapBytes for an inexpensive Linux distro retailer.

Thanks to Windows forum moderator GolProRM for contributing to this tip.