It's been almost 20 years since Linux was first released into the world. The OS, which is free for anyone to use and modify however they like, has been put to a lot of uses.

Today, a vast number of servers run Linux to serve up web pages and applications, while user-friendly versions of Linux run PCs, netbooks, and even Android and WebOS phones.

One incredibly useful way that Linux has been adapted to the needs of modern computer users is as a 'live CD', a version of the operating system that can be booted from a CD (or a DVD or, in some cases, a USB drive) without actually being installed on the computer's hard drive. Given the massive RAM and fast CPUs available on even the lowest-end computers today, along with Linux's generally lower system requirements compared to Windows and Mac OS X, you can run Linux quite comfortably from a CD drive.

Live discs allow you to radically transform the nature of the machine you're working on - without modifying the installed operating system and software at all. There are a number of reasons you might want to do this. The most obvious is to test a new version or different distribution of Linux before deploying it, saving yourself the surprise of incompatible software or non-functional hardware after installation. But even if your business does not plan to deploy Linux as a desktop or server operating system, there are still good reasons to have a live Linux CD or two on hand.

Live CDs are great for system diagnosis and recovery when disaster strikes; they're also useful for securing and testing your network. And for road warriors, the ability to boot up a familiar, customised operating system on any machine, anywhere in the world, has an obvious attraction - as do specialised live distributions designed to provide security and anonymity for workers with sensitive data or communications to protect.

Live discs are read-only, which means they're quite secure, since malware can't make any changes to the core system. If you do get an infection, it disappears as soon as you reboot.

Here are five ways to use live Linux in your business, as well as pointers to distributions best suited to each particular task.

NEXT PAGE: Test-drive Linux

  1. What live discs can do
  2. Test-drive Linux
  3. Restore failed systems
  4. Creating a live USB from a CD image

Live CDs, DVDs or USB drives let you run Linux without actually installing it. Here are five ways to use them.

1. Test-drive Linux

Over the years, Linux has developed from a usability nightmare into a fairly straightforward desktop operating system. With professional-quality productivity tools like OpenOffice.org for creating documents, spreadsheets and presentations and GIMP for image editing, as well as versions of familiar applications such as Firefox, Thunderbird, Adobe Reader and Flash, most common business tasks can be done pretty easily on a Linux system.

You can see how well adapted Linux is to your business by running several of the most popular desktop distributions from a live CD. Perhaps the most refined and user-friendly desktop system available right now is Ubuntu, which includes just about every application you could ever ask for, from business productivity apps to programs for multimedia editing, web design, running databases, serving up web pages and chatting online.

Ubuntu, one of the most popular desktop Linux distros available, comes preloaded with the open-source office suite OpenOffice.org.

Ubuntu's installation disk is itself a live CD, so if you decide to install the system later you can just run the installer from the Ubuntu desktop.

2. Recover aging hardware

Linux in general has lower system requirements than other contemporary operating systems, but there are a few distributions that are specially designed to take advantage of old, even ancient, computer hardware, letting you squeeze a few more years of life out of systems you wouldn't even think of running Windows on - including machines with broken hard drives.

Both Damn Small Linux (DSL) and Puppy Linux are designed for older systems, requiring only a Pentium 486 or equivalent CPU and 128MB of RAM to run well. DSL can even run with just 64MB of RAM. Both launch a usable, if somewhat stripped down, user interface that's perfect for tasks like sending and receiving e-mail, creating documents and surfing the web - in other words, basic administrative tasks.

3. Secure your network

Linux is already one of the more secure operating systems, since it was designed from the start as an Internet-connected system. Running it from a live CD makes it even more secure, since the disk image cannot be modified. Several distributions take advantage of the inherent security of the live CD to transform old computer equipment into powerful secure gateways for your network.

Zeroshell can be installed on any PC with a 233MHz processor and 96MB of RAM to transform it into a fully featured gateway router and firewall. All the advanced features you'd expect from a modern gateway are present, including authentication via RADIUS server, quality-of-service monitoring and traffic-shaping, VPN and the ability to act as an 802.11a/b/g router on machines with the appropriate wireless cards.

NEXT PAGE: Restore failed systems

  1. What live discs can do
  2. Test-drive Linux
  3. Restore failed systems
  4. Creating a live USB from a CD image

Live CDs, DVDs or USB drives let you run Linux without actually installing it. Here are five ways to use them.

4. Restore failed systems and recover lost files

When Windows fails to boot, smart IT professionals reach for their live Linux CDs. Whether the problem is a corrupted operating system or a damaged hard drive, you can boot up Linux from the CD drive, allowing you to read and copy files, run diagnostics or perform other maintenance tasks like partitioning drives.

While most Linux distributions have an assortment of at least some useful diagnostic and recovery tools (and often, looking at a drive through another operating system can be immensely useful in itself), specialized distros like the Ultimate Boot CD (UBCD) designed to run from discs are ideal for dealing with technical problems.

UBCD is the Swiss Army knife of recovery discs, containing more than 100 tools for performing deep sector-by-sector analysis of a hard drive's physical surface, recovering deleted or damaged files, rebuilding file tables, examining boot-sector errors and plenty more.

5. Work anonymously

Transform any computer into a paranoia-inspired privacy powerhouse using a CD-based distribution such as TAILS, The (Amnesic) Incognito Live System. With TAILS, you can surf the web in total privacy - all outgoing traffic is anonymised using the Tor service, which bounces your packets through random servers worldwide before delivering them to their destination.

In addition, the software included with TAILS is configured for privacy by default: Firefox comes with JavaScript and cookies disabled; the e-mail client, Claws, includes integrated GnuPG encryption; the Pidgin IM client is configured for Off-the-Record messaging, which encrypts and strips identifying information from your messages; and so on. Since it boots from a Live CD and saves no information on the host machine, once you remove the disc all traces of your activity simply disappear.

Find more live Linux distros

These choices only scratch the surface of the available Linux systems that can be run from a live CD - Wikipedia's 'List of Live CDs' entry names about 100 different Linux versions with live CDs, as well as live CDs based on other operating systems such as BSD, Solaris and even Windows. If you have a preferred Linux version, check the list - chances are it will run from a live CD, with all the portability and security benefits that implies.

NEXT PAGE: Creating a live USB from a CD image

  1. What live discs can do
  2. Test-drive Linux
  3. Restore failed systems
  4. Creating a live USB from a CD image

Live CDs, DVDs or USB drives let you run Linux without actually installing it. Here are five ways to use them.

Creating a live USB drive from a live CD image

Although live CDs have a lot of advantages, they don't fit in your pocket easily, which means you may not always have one around when you need it. Fortunately, most live CD images can be installed onto a USB flash drive, giving you most of the benefits of a live CD.

Since most modern computers can boot from a USB drive, live USBs can be used in almost all of the situations a live CD can. The fact that a USB drive can be written to is both a benefit and a drawback - on one hand, it isn't as resistant to intrusion as a read-only CD, but on the other hand, you can save configuration details, store documents and other files, and download and install new software to a USB drive, which you can't do with a live CD.

If trading a bit of security for the portability of a flash drive seems worthwhile to you, there are several tools that will easily install a live CD image to a USB drive. Two of the easiest to use are the Universal USB Installer and the Linux Live USB Creator, both of which walk you step by step through the process of converting a CD image to a USB drive.

They have each been tested with various versions of Linux - though the two lists of versions that each one has been tested with differ slightly - and you can try any untested system with either and it might still work. However, there are just too many versions of Linux out there for either to guarantee 100 percent compatibility. One nice feature both offer is the ability to configure a USB-based Linux to run in a Windows-based virtual machine, so you can effectively launch Linux within Windows - that's useful if you're using a public machine that you're not able or allowed to reboot.

See also: Chip giants team up to take Linux mainstream

  1. What live discs can do
  2. Test-drive Linux
  3. Restore failed systems
  4. Creating a live USB from a CD image