terms of CPU sales." The design remains somewhat obscure because most of those uses were as embedded microcontrollers where the chip inside the device is rarely identified, as opposed to products like home computers where the CPU inside is better known. Among its few better-known uses were the Fairchild Channel F in 1976, and in the VideoBrain Computer system in 1977. Both were wiped out of the market by the introduction of the Atari 2600 in 1977. Fairchild also produced a number of engineering and hobby boards using the F8. Kit 1 was a single circuit board with the 3850 CPU, 3851 PSU, and 3853 SMI. The PSU contained a program known as "Fairbug" that could be accessed using a terminal connected to the CPU over its 8-bit I/O port. The F8 was discontinued in the mid-1980s, with the final last-time purchase by Innovative Data Technology, San Diego, CA for use in their flagship 1/2" 9-track tape drive the TD1050 series used for billing data interchange by telecom operators. Description Chip family A typical computer system generally requires a CPU, some form of input/output to communicate with the outside world, and memory holding the program code and user data. Typically, I/O would be handled by dedicated chips, and memory would be accessed through an address bus selecting locations in external memory and then returning that data to the CPU over a data bus. Depending on the design, the I/O would communicate with the processor over a dedicated bus, or alternately by placing data in memory and then having the CPU read it. Moving data between all of these different units required additional "glue" circuitry. The F8 was designed to split these duties up in order to make minimalistic implementations possible. In theory, one could place all of these functions on a single chip, but in the era of 40-pin chips there were simply not enough pins to connect all of these functions up. In particular, implementing a 8-bit data bus, 16-bit address bus and another 8-bit I/O bus would leave only 8 more pins for every other function, from power supply and ground to the various clock signals and control lines. Other designs sometimes multiplexed the address and data lines so the same pins could be used for multiple functions, at the cost of requiring more cycles to complete an operation. The F8 addressed this problem by internalizing some of