Developed by the UK's Raspberry Pi Foundation, the Raspberry Pi is a credit card-sized computer powered by a processor that's similar to those in today's smartphones. Its small size and low price (around $35) have made it a popular device with which to introduce students and hobbyists to computer programming.
David Braben on Raspberry Pi | Features | Edge Online
The Raspberry Pi B+ was released on July 14. While the new model has the same processor and memory as the previous model (the Raspberry Pi B), the B+ adds two additional USB 2.0 ports (for a total of four) and draws less power. The B+ uses microSD cards for storage.
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The Raspberry Pi also has an Ethernet port, an HDMI port, and 512MB of memory. While B+ uses microSD cards for storage, older models used SD cards. Its small size and ability to play high-definition video has also made it a popular choice for basic home theater PCs.