One of the most fun and useful aspects of Linux is it supports more hardware platforms than any other operating system. IA32, IA64, Sparc, PPC, Alpha, ARM, HPPA, MIPS, and gosh knows how many more. This gives the hardworking system or networking administrator unparalleled flexibility. You may repurpose or cannibalize old hardware, or spec out new hardware exactly as you like.
This holds true at both ends of the scale, both large and small. Today, we'll take a look at the tiny end of things. Here, we have single-board computers, Mini-ITX, and Small Form Factor. Here a few examples to look. While these have my personal stamp of approval, we're not recommending them over other devices because there are so many good ones. This is just to give you an idea of the possibilities.
This makes a dandy router, firewall, or wireless access point. It has two 10/100 Ethernet ports, 64 Mbyte SDRAM, and is powered by a 133Mhz 486 processor. Data storage is handled by attaching a CompactFLASH card to the onboard Type I/II socket. The two mini-PCI type III sockets and two PC-Card/Cardbus slots mean many expansion and customization possibilities. These little boards are tough, quiet, and low-power.
is very popular and has inspired an amazing amount of creating case modding. These are more powerful and typically include onboard multimedia and use laptop hard drives, which makes them suitable for thin clients, basic PCs, multimedia controllers, and more powerful firewall/gateway devices.
"Small Form Factor" is a catch-all term that usually refers to a stylish cube, like the popular Shuttle systems. These hold beefier power supplies and CPUs, like dual-core Athlon 64, so you can do some serious work with them while looking elegant.
You have a huge range of choices in vendors and hardware options, so it pays to shop around. Combine these with Linux, and you can to build and customize devices exactly to your specifications, and possibly save some money as well. So the next time your friendly "network appliance" salesman pays you a visit, you can tell him you don't need his closed, proprietary, inflexible box with its bale of expensive software licenses because you already have everything you need.