D-37C - D-17B Comparison

D-17B Comparison

Both the D-17B and the D-37C computers were designed and built by Autonetics, then a division of North American Aviation, later a division of Boeing, for the real time guidance and control of a Minuteman ICBM from launch to detonation. The D-17B is a component of the NS-10Q missile guidance system for the Minuteman I, while the D-37C is a component of the NS-17 missile guidance system for the Minuteman II. There are many basic similarities between the two designs. They are both synchronous, serial machines with fixed head disks for primary memory. They have two-address instructions, half and whole word precision, and many similar instruction operator codes. The differences in the two computers are based mainly upon their differing technologies. The D-17B was built in 1962 using transistors and other discrete components to realize its logic circuits. On the other hand, the D-37C was built in 1964 using small scale integrated circuits made by Texas Instruments with discrete components only in the internal power supplies.

Comparison of D-17B and D-37C ----------------------------- Model: D-17B D-37C Year: 1962 ` 1964 Type: Serial, Synchronous Same Number System: Binary, fixed point, " 2's complement Data Word Length: 11 or 24 bit (double- " precision) Instruction Word Length: 24 bit " Number of Instructions: 39 57 Execution Times: Add 78 1/8 microsec Same Multiply 1 millisec Same Divide (software) 2 msec Clock Channel: 345.6 kHz Same Addressing: Direct of entire memory Direct within Bank (1/4 of memory) Memory: Word Length 24 bits plus 3 timing Same Type Ferrous oxide-coated " NDRO disc Cycle Time 78 1/8 microsec minimal " Capacity 5,454 or 2,727 words 14,444 or (double precision) 7,222 words Input/Output: Input Lines 48 digital 65 digital 32 analog Output Lines 28 digital 45 digital 12 analog 16 analog 3 pulse 8 pulse Program 800 5-bit characters/sec Same Physical Characteristics: Dimensions 20" high, 29" diameter 20.9 x 6.9 x 9.5" Power 28 vdc ±1 v 28 vdc ±1.7v at 19A at 15A Circuits: Discrete DRL and DTL IC DRL and DTL Software: Minimal delay coding Same machine language modular special-purpose subroutines Reliability: 5.5 years MTBF (classified)