5 ways to use bootable Linux live discs

In the almost 20 years since Linux was first released into the world, free for anyone to use and modify however they like, the operating system 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 nonfunctional 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, customized operating system on any machine, anywhere in the world, has an obvious attraction -- as do specialized 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.

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'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 233-MHz 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.

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 anonymized 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.

Logan Kugler is a frequent Computerworld contributor. His most recent article was "10 free Android apps for staying in the know."