A Live CD is a bootable compact disk that contains its own operating system (OS). Booting to a Live CD allows a user to try out alternate operating systems without making changes to the computer’s existing OS, hard drives or files. Live CDs, sometimes referred to as LiveDistros are used extensively for various incarnations of the GNU/Linux operating system.
When power is supplied to a computer, the first thing the computer does is process a set of instructions read from the BIOS, or the Basic Input/Output System chip. Settings contained here can be user-modified but typical default settings instruct the computer, among other things, to boot off the hard drive after checking to make sure there is no bootable compact disk in the CD/DVD drive.
If the computer finds a Live CD in the drive, it will boot to that system rather than the installed OS. Once the computer boots to the Live CD the user is free to explore the operating system without compromising the host computer. To get back to the locally installed system, simply remove the Live CD from the CD/DVD drive and reboot the computer, allowing it to boot from the hard drive.
Live CDs are useful for a number of reasons. For one, a user no longer has to invest time and internal storage space to set up a dual boot system in order to try out a new OS. Moreover, many Linux distributions such as Ubuntu are self-sufficient systems with a suite of free built-in programs including a word processor, spreadsheet program, graphics editor and the award-winning FireFox™ Web browser. This means one can take a Live CD to any computer to get work done without invading the desktop, workspace or system of the host computer.
If attempts to boot from a Live CD fail and the system boots to the hard drive, you’ll need to change your BIOS settings. To do this, hold down the Delete key during the beginning moments of the boot process. When the BIOS menu pops up, navigate to the options that will allow you to change the order of bootable devices. Rather than listing the hard disk as the first device to check, change the settings so that the computer will try the CD drive first. These settings can be saved without creating problems. When there is not a Live CD in the drive, the computer will boot from the hard drive.
Various Linux distributions are available online, many free. In some cases you can request a Live CD be sent through the mail, though this might incur charges for materials and shipping. You can also opt to download a Live CD file and place it on a CD yourself. The file will be large, however, and unsuitable for download through low-bandwidth connections such as dial up.