In short, Live-CDs (or DVDs) allow you to boot your computer into a fully functioning Operating System (OS), from a CD or DVD containing the OS, without any need for installing the OS or any additional applications onto your hard-drive - and, in as little as one minute! Perhaps this does not sound very exciting at first. But, consider the length of time it takes to perform a complete install of Microsoft Windows XP, and a few popular programs like MS Office, Adobe Acrobat, and the likes to your computer's hard-drive so that you can have a "working machine" (or, at least one that has enough installed to be useful). At best, you would probably face 2 or 3 hours of "fun" trying to get a machine up and ready, and perhaps another 2 or more hours just to apply the latest security updates, service packs, and other critical fixes. There is a better way!
Live CD's must detect your machine's hardware configuration on-the-fly, and configure the OS to make use of that hardware upon booting. This is quite a feat, seeing that this same task takes MS Windows an exorbitant amount of time to accomplish even when installing to your hard-drive. Most newer variants even detect my Gigabit Ethernet card and high-end graphics cards OK, though none to date have detected my Linksys Gigabit Cardbus adapter successfully (I wait eagerly for that to change) on my notebook.
So why should you be interested in a LiveCD, especially if you do not particularly want to use Linux? Well, I have provided the following few reasons why I consider this technology so important:
- Virus Protection: since you are running from a CD, your system is rather isolated from the impact of any virus you may encounter. If one was encountered, simply rebooting from the CD will restore the original pristine state of your operating environment. No changes are saved to the CD between reboots, though you can save documents and settings changes to a USB KeyDrive or a partition on your hard drive if you choose.
- System does not "degrade" in performance over time: unlike a hard-drive install of Windows or any other system that suffers from slowdown as the number of temporary files increases, security-updates have been applied, and a host of other software "patches" are applied. The CD remains the same each time you start up -- a nice clean "fresh" system!
- Privacy and Security: once again, you are running your OS from a CD and in RAM; so, once you turn off the computer, there is no trace of what you were doing while running the OS (unless you specifically choose to save such information to a more "permanent" device). Don't worry about leaving copies of confidential files in "My Documents" or what have you; for, if you did, they will just not exist next time you boot from your CD. There will not be any "malware" or "cookies" left to track your Internet activity either - so there is no chance someone will acquire any saved user/password information from anywhere on your machine (if any was stored, it is wiped when you reboot).
- Debugging and Forensics for your Windows machine: even if your Windows installation has failed utterly, you can perhaps recover valuable files from your hard-drive by booting with a Linux LiveCD and accessing what is left of your file-system from Linux. Then, you can copy files off to somewhere while attempting to repair your Windows environment. And, with some LiveCD variants, you can use tools like CaptiveNTFS to actually modify the contents of Windows files that may be the cause of your system failure.
- Testing new Software: if you are interested in trying out various popular open-source softare prior to installing on your hard-drive, this is a great way to go. Not only the OS can be tested, but most LiveCD images include a range of applications like OpenOffice, Gaim, FireFox, and many, many more - all preinstalled and ready to run!
- Portability: you can run these CDs from nearly any computer that has a CDROM or DVD drive; regardless of what OS is already installed on those PCs or Mac systems. Simply pop in the CD and reboot into your Linux environment of choice.
- Speed: you can have a fully operational computer in as little time as it takes to boot from CDROM. Compare that to the length of time it takes to perform a complete install of Microsoft Windows XP, and a few popular programs like MS Office, Adobe Acrobat, and the likes. When I get a new computer, I quite often first "test drive" the computer using a LiveCD, prior to committing many hours to installing software on my hard-drive.
You can also easily run your LiveCD from within a Virtual Machine (VM) using VMWare's free VMWare Player technology, coupled with this tiny ISO-Image-running-virtual-machine-config. I say tiny, because you only need to download one file (vmwarez.com-Generic-LiveCD
I personally prefer Kanotix and Kubuntu Linux variants for their Live CDs, and I have had excellent experiences with these distributions automatically detecting all of my hardware and making it available from within the OS. A great resource for locating additional Linux derivations and Live CDs is distrowatch.com. This site is a fantastic resource for keeping up with the latest Linux and open-source distributions, applications, and the likes.
Though many applications are pre-installed in the LiveCD environment, you may wish to have other applications available. Have no fear, most new LiveCD setups include a technology called UnionFS that allows you to actually "install" additional software. Kanotix makes this even simpler by supporting "klik" applications, which can literally be installed with a click!
Now, wouldn't it be fantastic if Microsoft would release a Live DVD (yes, a DVD would be necessary due to the bloated size of the OS and applications) version of Windows XP that came with pre-installed Microsoft Office and other essential Windows applications? There have been many times where I so wish I could have such a thing available instead of facing the hours of installation and preparation time it currently takes to get a Microsoft-centric system up and running from scratch. I would not count on this happening any time soon though, since Microsoft will unlikely be able to find a way to thwart the subversive efforts of software pirates that would all to quickly make illegal copies of such a thing if it existed! (not that pirates don't do that already with existing Windows and Office software).
So, download an ISO (i.e., burnable CD/DVD ROM Image file) for a LiveCD today, create your bootable media from it, and give it a test run. Once you get acquainted with these OS's and recognize their usefulness, they will likely become an invaluable tool you keep close at hand.