First released in 2012, the Raspberry Pi is a single-board computer created by the Raspberry Pi foundation in the United Kingdom. It was designed to be a small, cheap computer that could be used in schools to teach science to children. Since its introduction, almost four million Raspberry Pis have been sold.
These machines use a 700 MHz ARM processor, and models can come equipped with either 256 MB or 512 MB of RAM. They can support up to five USB 2.0 ports. Raspberry Pis may utilize a MicroSD card or flash memory (up to 4 GB) for non-volatile storage, and uses HDMI for digital audio and video output. There is no on-board network interface, but they support Wi-Fi and Ethernet networking via USB.
Raspberry Pis commonly run Linux as their operating system. There are versions of Archlinux, Fedora, Puppy Linux, Slackware, FreeBSD, NetBSD, openSUSE, and RISC OS available for the Pi, as well as Raspbmc; an operating system specifically created for using the Pi as a digital media center or HTPC.