The Linux LiveCD

A relatively new phenomenon in the Linux world is the bootable Linux CD distribution, which lets you see what a Linux system is like without actually installing it. Most modern PCs can boot from a CD instead of the standard hard drive. To take advantage of this capability, some Linux distributions create a bootable CD that contains a sample Linux system (called a Linux LiveCD). Due to the size limitations of a single CD, the sample can’t contain a complete Linux system, but you’d be surprised at all the software they can cram in there. The result is, you can boot your PC from the CD and run a Linux distribution without having to install anything on your hard drive.

It’s is an excellent way to test various Linux distributions without having to make changes to your PC. Just pop in a CD and boot! All of the Linux software will run directly off the CD. There are many Linux LiveCDs that you can download from the Internet and burn onto a CD to test-drive.

Linux LiveCD Distributions
Knoppix - A German Linux, the first Linux LiveCD developed
SimplyMEPIS - Designed for beginning home Linux users
PCLinuxOS - Full-blown Linux distribution on LiveCD
Ubuntu - A worldwide Linux project, designed for many languages
Slax - A live Linux CD based on Slackware Linux
Puppy Linux- A full-featured Linux designed for older PCs

You may notice something familiar in Table 1-8. Many specialized Linux distributions also have a Linux LiveCD version. Some Linux LiveCD distributions, such as Ubuntu, allow you to install the Linux distribution directly from the LiveCD. You can boot with the CD, test drive the Linux distribution, and, if you like it, install it onto your hard drive. This feature is extremely handy and user friendly.

As with all good things, Linux LiveCDs have a few drawbacks. Because you access everything from the CD, applications run more slowly, especially if you’re using older, slower computers and CD drives. Also, because you can’t write to the CD, any changes you make to the Linux system will be gone the next time you reboot. But there are advances being made in the Linux LiveCD world that help to solve some of these problems. These advances include the ability to

• Copy Linux system files from the CD to memory
• Copy system files to a file on the hard drive
• Store system settings on a USB Memory Stick
• Store user settings on a USB Memory Stick

Some Linux LiveCDs, such as Puppy Linux, are designed with a minimum number of Linux system files and copy them directly into memory when the CD boots, which allows you to remove the CD from the computer as soon as Linux boots. Not only does it make your applications run much faster (because applications run faster from memory), but it frees up your CD tray for ripping audio CDs or playing video DVDs from the software included in Puppy Linux.

Other Linux LiveCDs use an alternative method that allows you to remove the CD from the tray after booting. It involves copying the core Linux files onto the Windows hard drive as a single file. After the CD boots, it looks for that file and reads the system files from it. The Ubuntu Wubi project uses this technique to move the LiveCD contents to a single file stored in the Windows drive on the PC. From there you can boot directly into Ubuntu.

A popular technique for storing data from a live Linux CD session is to use a USB Memory Stick (also called a flash drive and a thumb drive). Just about every Linux LiveCD can recognize a plugged-in USB Memory Stick (even if the stick is formatted for Windows) and read and write files from it. This capability allows you to boot a Linux LiveCD, use the Linux applications to create files, store them on your Memory Stick, then access them from your Windows applications later (or from a different computer).

Source of Information : Wiley Ubuntu Linux Secrets