for assisting product development engineers who interacted with FAIR-BUG from a Teletype. Fairchild extended FAIR-BUG as KD-BUG, for use with a keyboard and display. FAIR-BUG main commands are single ASCII characters drawn from the set {A, B, C, D, E, F, G, I, L, M, N, P, R, S, W}. Register and memory locations were keyed in as parameters immediately after the command identifier. For example, the command results in the content of 16 bytes of memory being typed out by the Teletype. FAIR-BUG commands address all memory locations and all registers. These locations can be examined or modified by the programmer. FAIR-BUG contains five subroutines which are used in processing commands: Input 2 ASCII Bytes; Output 1 ASCII byte; Output the string CR, LF, Null; Output 1 ASCII byte; Input 1 ASCII Byte from a Parallel Input Device. FAIR-BUG is essentially a random access management routine for all memory, both RAM and ROM, and all registers including program counter, data counter, and scratchpad. The programmer is given the ability to plant any of the 70+ machine code instructions or operands into memory locations. The programmer can then use the G command to load a specific address into the program counter and execute the routine at that address. The objective in providing the FAIR-BUG routines in 1975 was to assist engineers in speeding up the creation of applications for the F8 ICs. Notes References Citations Bibliography Datasheet: http://datasheets.chipdb.org/Fairchild/F8/fairchild-3850.pdf Patent: http://www.google.com/patents/US4086626 External links Free On-Line Dictionary of Computing The Great CPU List 8-bit microprocessors