The AVR is an 8-bit RISC single-chip microcontroller which was developed by Atmel in 1996. The AVR was one of the first microcontroller families to use the on-chip flash memory for program storage, as opposed to the one-time programmable ROM, EPROM, or EEPROM used by other microcontrollers at the time. Recently a lot of enthusiasts become acquainted with the AVR microcontrollers thanks to the Arduino project. The original Arduino board featured ATmega8. The strong sides of AVR microcontrollers are the low price, and the availability. It is very important to mention the high quality of the free software tools needed for developing (IDE, compiler), provided by Atmel. Also there are solid tools for development under Linux. The main downside of the AVR architecture is the relatively low microcontroller speed - they are not the best choice for heavy processor tasks and multitasking. If you are searching for a board or a microcontroller capable of running Linux - look in the ARM category. Atmel (AT) is one of the producers of ARM microcontrollers.