Don't throw away those old PCs yet. Whether you're cleaning out or upgrading the computers in the office or at home, you should be able to find something to do with them.
As we'll discuss, you can use them for experimentation, routing, security, file or Internet serving, and more. Make one of the projects your late-night endeavor on the weekend or your new project at work.
#1 Install Ubuntu or other distribution to experiment with Linux
If you haven't already, you could discover the world of free and open source computing by fiddling around with Linux. Within an hour or so, you can download and install Ubuntu, or one of the other thousands of distributions (distros) onto your old PC. You can even test it out before installing anything to your hard drive, using the live CD mode of some distros.
Ubuntu has become very popular, especially for Linux newbies. "Ubuntu" is an ancient African word, meaning "humanity to others", hence their philosophy and mission to better the computing world. You can read more about this distro and download Ubuntu from its site. You might also want to check out a previous article of mine on this site: Discovering Ubuntu as a Windows User. To discover other distributions, check out DistroWatch.com.
Once you boot into a desktop version of Linux, you'll see that though it looks different from Windows it still has the same main features. There's still a start menu--usually better organized than in Windows--and icons on the desktop. Average users should be fine typing up documents, browsing the Web, and doing other basic tasks.
The biggest advantage is that you'll now have access to hundreds of thousands of totally free applications. Some are small projects, however some rival that of their commercial counterpart, such as OpenOffice.org and Microsoft Office. Most distros are actually loaded with all the day-to-day software you'll need: an office suite, email client and calendar, Web browser, photo editor, and more.
For additional applications, you can use the Package Manager to search for and install other software that's listed in the distro's repositories; or download programs directly from a developer's site and build them manually.
Linux is actually the operating system for many computer and networking devices. The rest of the ideas in this article also use Linux-based software.
#2 Make it a router with RouterOS or ZeroShell
Advanced networking features, such as found in Cisco equipment, can be at your fingertips with little or no cost. Linux-based operating systems can convert your old PC into a multi-purpose LAN server. Use it to replace your off-the-shelf router by running the firewall for your network and sharing the Internet access (with NAT). You might even connect your offices together using the VPN server and client, offer public access by configuring the captive portal, or use balancing and fail-over for redundancy. The features and solutions are essentially endless.
Two popular projects you should look into are RouterOS and ZeroShell. ZeroShell is free and can be ran from the CD with the configuration saved to a hard or flash drive. After minimal configuration at the console, you can administer it via a Web browser on a remote computer. RouterOS has been around longer and is more established. It installs directly onto a drive and has multiple configuration interfaces, including Web-based and a custom GUI application.
For help with ZeroShell, check out my tutorial series on one of our sister sites, LinuxPlanet.
#3 Make it a LAN file server with FreeNAS
If you do a lot of file sharing on your network, you might have looked into using network attached storage (NAS) rather than creating basic shares with Windows. You may have also noticed that NAS enclosures (basically small computers) don't run cheap, and then you have to buy the hard drives too. However, you can create your own NAS enclosure by installing a FreeBSD-based NAS server, FreeNAS, on your old PC.
Using a NAS server means you don't have to worry about other PCs being on in order to access Windows shares. Using FreeNAS gives you a central storage place that's always accessible. It also provides better and easier control over shares. It can store user details and authenticate users. If using Windows shares, you'd have to duplicate every user account on all the computers for similar protection of shares.
Like other NAS servers, FreeNAS gives you recycle bin support. If you delete a file from a Windows share, it's gone forever. However, if you delete a file from a FreeNAS share, it will go into the trash can, where you can later permanently delete it or recover it.
FreeNAS supports many different sharing protocols: CIFS (SMB/samba) for Windows, NFS for Linux/Uniux, and AFP for Mac OS X. Plus it supports FTP, RSYNC, and iSCSI. It even has an iTunes/DAAP server, so you can share files among your iPods. It also features a built-in BitTorrent server.
#4 Run Web, Email, FTP, and other Servers with Linux
Though Web hosting prices can be very reasonable, you might find it interesting to host your own Web site. It might also be useful when developing an Intranet or when working with special applications. You could host other services, such as an email server with a POP3 and SMTP server, file access with a FTP server, or database access using a MySQL server.
The two major Web servers, the Linux-based Apache HTTP server and Microsoft's IIS (available in professional editions of Windows) server, are actually free to use.
When installing Apache, you can either install just the Web server application (and other components separately as needed) or install a Web server software distribution or package. When using Apache, it's best to install a package of servers. Apache2Triad is a great package for Windows. If using Linux, you might want to include LAMP when installing Ubuntu Server Edition.
You might want to check out a Server Room DIY series I did for a sister site, ServerWatch, on self-hosting.
#5 Turn it into a hotspot with ZoneCD
Would you like to offer wireless Internet access to your visitors or neighbors, but don't want to spend hundreds on a hotspot gateway? Well, you don't have to; you can have a Wi-Fi hotspot up and running within an hour using your old gear. One solution is ZoneCD from PublicIP.
ZoneCD is a Linux-based live CD that provides Wi-Fi authentication and Web content filtering. It boots directly from the disc and there are no changes made to the hard drive. It requires only 128MB of RAM, a bootable CD-ROM drive, and a floppy drive or USB thumb drive to store the configuration. Two Ethernet cards are also needed. One plugs into the Internet and the other into a wireless router or access point (AP).
I discuss this and other hotspot solutions in one of my books, Wi-Fi Hotspots: Setting Up Public Wireless Internet Access.
Eric Geier is an author of many computing and networking books, including Home Networking All-in-One Desk Reference For Dummies (Wiley 2008) and 100 Things You Need to Know about Microsoft Windows Vista (Que 2007).