You know the devices; possibly the most well known is the Marvell plug computer line. Its flagship product, the SheevaPlug, offers a 1.2GHz ARM-compatible Marvell Sheeva processor, USB 2.0 and gigabit Ethernet, 512Mb Flash RAM and 512Mb DDR2 RAM.
Those specifications are not anything to write home about, particularly when you consider even the teeniest Netbook ships with 4Gb of flash memory.
This is where you have to actually see the device; check out the plug computer info sheet from Ionics EMS and you will see just why these gadgets are dubbed 'plug computers' and 'wall warts'. They literally are no bigger than a typical power brick for a powered USB hard drive or some phone chargers.
Yet, that's the whole computer - and that's where the appeal comes in. Well, that and the sub $US 100 price tag.
Additionally, a plug computer uses 5 watts under normal operations, in contrast to the typical 25 to 100 watts for a dedicated PC.
What can you possibly do with such a small device? Ahh, this is where Linux shines.
First things first, you won't run Microsoft Windows on this gadget. Not even Windows 7 Starter edition will fit or the aging, but popular, Windows XP.
Linux does the job admirably, with even the most full-featured distro like Debian being able to slot into the flash memory provided you're economical with what you install (scrap Gnome and KDE for starters!). Or Damn Small Linux and other distros of its ilk will do the job just fine too.
Linux has always had a stellar reputation for its server capabilities and while plug computers aren't powerhouses they can serve as a tremendously compact, a remarkably discrete and even super-portable network server.