The Raspberry Pi is a small computer the size of a credit card. The system consists of chips from Broadcom, and comes with the Linux based operating system Raspbian. The Raspberry Pi Model B Rev. 2 is the second edition of the B-model, which has more memory (512MB), an extra USB port and a 10/100 Ethernet controller. The company now offers "apps" to this little slice of Pi on Raspberry's own Pi Store.