12/12/2013
The First Recognizable Modern Embedded System: Apollo Guidance System (July 20, 1969):
Certainly one of the most outstanding achievements of the 20th century was the landing of a human on the moon on July 20, 1969. The use of computing technology to get there is frequently alluded to, but exactly kind of hardware and software were required?
Vast amounts of computational power in the form of mainframes and minicomputers performed essential mission-planning calculations on the ground before, during, and after the trip. Less well known is the story of a 70-lb box of integrated circuitry and an attached control panel that performed real-time guidance and control and which served as a lifeline to the astronauts descending to the lunar surface. Assemblers at Raytheon testing building AGC modules.
The Apollo Guidance Computer (AGC) was built by Raytheon and used approximately 4000 discrete integrated circuits from Fairchild Semiconductor. Spanning nearly a decade of project development, the AGC began as a research project at the MIT Instrumentation Lab in Cambridge, Massachusetts. The lab was home to the world's foremost experts in guidance and control, where Polaris and Poseidon missile guidance programs were developed. However, until Apollo, all computations for the equations of motion in these systems were performed by analog computers.
Specifications:
Instruction Set: Approximately 20 instructions;
100 noun-verb pairs, data up to triple-precision
Word Length: 16 bits (14 bits + sign + parity)
Memory: ROM (rope core) 36K words; RAM (core) 2K words
Disk: None
I/O: DSKY (two per spacecraft)
Performance: approx. Add time - 20us
Basic machine cycle: 2.048 MHz
Technology: RTL bipolar logic (flat pack)
Size: AGC - 24" x 12.5" x 6" (HWD); DSKY - 8" x 8" x 7" (HWD)
Weight: AGC - 70 lbs; DSKY - 17.5 lbs
Number produced: AGC - 75; DSKY: 138
Cost: Unknown.
Power consumption: Operating: 70W @ 28VDC; Standby 15.0 watts
