Back in personal technology prehistory—you know, before computers were idiot-proof enough to grace any living room—it was tough to use a PC without possessing an intimate understanding of how and why it worked. The advent of prefabricated machines and graphical operating systems has helped the industry explode like those of us who witnessed its birth could never have dreamed of, but that remarkable success has come at the cost of the pioneering spirit that started it all. But all hope of regaining that foundational force it is not lost.

The Raspberry Pi ($35, as tested), a tiny and brilliantly inexpensive proto-computer, encourages exactly the kind of exploration and tinkering that are nowadays often relegated to even the fringes of the DIY and enthusiast communities, and demands your active participation and intellectual engagement. But be forewarned: You cannot be a passive user. From the instant you pull it out of its box, you're fully committed, and if you don't know what you're doing, you're going to have to learn quickly. If you think that sounds like fun for you and your family, the Raspberry Pi SEE IT is one computer-project you'll love sinking your teeth into.

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Features
Before getting into what the Raspberry Pi can do, we need to examine what you get with it. The system comes in two different flavors: Model A (for $25) and Model B ($35). The main differences between the two are USB ports (Model A has one, Model B has two), Ethernet (Model A doesn't have it, model B does), and power usage (in no small part because of that Ethernet jack, Model B uses almost half again as much power as the Model A). But in most other respects, the hardware is the same.

And what hardware it is! The Raspberry Pi is a Broadcom BCM2835 system on a chip (meaning, for these purposes, a bare circuit board), which unites a 700MHz ARM1176JZF-S CPU with a Broadcom VideoCore IV GPU, and 256MB of SDRAM. Those USB 2.0 ports are your only external data connectivity options, although there are two video outputs in the form of composite RCA and HDMI ports, a 3.5mm audio output, and an SD/MMC/SDIO card slot that is the extent of how you can access storage. The Raspberry Pi draws its power from a micro USB adapter, with minimum ratings of 500mA (2.5 watts) for the Model A and 700 mA (3.5 watts) for the Model B—but you'll need to provide it for yourself, as one does not come with the Raspberry Pi. (Chances are you'll be able to repurpose the charger for your mobile phone or tablet.) Oh yeah, and did we mention that, measuring about 0.6 by 2.1 by 3.4 inches (HWD), it's not much bigger than a credit card?

In other words, the Raspberry Pi is as basic as basic can be. And that's exactly the point. It's not designed for performance—more on that in a minute—it's designed as a platform: for education, for expansion, for technological enlightenment. And at that it succeeds. But its bare nature and lack of even rudimentary features—in addition to the lack of an included power cable or even case, there's no off button; plugging or unplugging the micro USB cable turns it on or off—mean that it isn't remotely for everyone. But even the adventurous types who are likely its target audience will need to approach it cautiously and be aware of the challenges it presents, particularly at the very start.

Setup and Software
From the hardware standpoint, setting up the Raspberry Pi could not be easier. Connect your USB keyboard and mouse, your display, your Ethernet cable (if you have a Model B), headphones or speakers if you want, then plugging in the micro USB cable to power it all up. Anyone, regardless of computer experience, will be able to get this far in seconds.

Software is another matter. Because there's no storage to speak of, your only recourse is the card slot—and that means loading a bootable operating system onto the card you're planning to use. Windows, of course, is out (it's too big, and no currently available version works with ARM chips anyway), but the Raspberry Pi website suggests and provides for download three Linux distros you can use instead: Debian "squeeze" (the recommended choice), Arch Linux ARM, and QtonPi, all of which have been optimized for use with the Raspberry Pi. After you select one, you'll need to write it (not just copy it) to an SD card using an application like Win32 Disk Imager. If this whole process is less brainless than configuring your average Windows or Mac operating system, it's still something that will not trouble most average users.

That might change once you turn on the Raspberry Pi. When you log in (with a default user name and password you can easily find online), don't be shocked if your first view is of an honest-to-goodness, mouse cursor–free command line. Believe it or not, it's easiest to do most setup tasks here, but if you're not fluent in Linux you may stumped trying to do anything as simple as change the time (which should be your first course of action—there's no battery for storing that information on the Raspberry Pi itself). If you're in desperate want of a desktop, you're a few keystrokes away from it, and installing new software to complement the bare-bones offerings on your OS isn't much more difficult.

However you look at it, it's an old-school way of thinking that might trip up those who've been out of the groove for a while (or were never in it in the first place). Even if you do run into trouble, there's a robust online community (including an official forum) where you'll be able to track down answers to even your most vexing questions in relatively short order.