System performance
Electrostatic storage capacity: 20,480 digits.
Magnetic drum capacity: 81,920 digits.
Magnetic tape capacity: More than 8 million digits without changing tape.
Addition and subtraction: More than 16,000 operations per second.
Multiplication and division: More than 2,000 operations per second.
Tape reading and writing speed: 12,500 digits per second.
Drum reading and writing speed: 8,000 digits per second.
Printed output: 180 letters or numbers per second.
Punched card input: 600 digits per second.
Punched card output: 400 digits per second.

All data are in maximum equivalent decimal values

Summary of system characteristics


Parallel operation.
Binary notation internally.
Control by stored program.

Word size:

Either 36 bits or 18 bits, including sign; approximately equivalent to 10 or 5 decimal digits and sign.
Accumulator has two extra bits for overflow.


Single-address system.
33 distinct operations.
Instructions are 18-bit words.

Computing speed:

Multiplication or Division: 0.456 millisecond.
Addition or Subtraction: 0.060 millisecond.

Electrostatic storage:

Capacity - 2048 words of 36 bits each.
Each full-word location may store a pair of 18-bit words.
72 tubes, 1024 bits per tube.

Magnetic drums:

Four drums, each with a capacity of 2048 words of 36 bits each, in basic system.
Average access time to first word of block - 40 milliseconds.
Reading or writing rate - 800 words per second.

Magnetic tapes:

Four magnetic tape units in basic system.
Material: Oxide-coated plastic tape, 1/2 inch wide.
Recording in 7 parallel channels, 6 for information and 1 for redundancy checking.
Tape may be written forward, read forward, or read backward under program control.
Density within a unit record: 200 words per foot.
Distance between unit records - 1 inch.
Maximum tape length on reel - 1400 ft.
Access time to start of unit record - approx. 10 milliseconds.
Reading or writing rate within unit record 1250 words per second.

Page printer:

Rate - 150 lines per minute.
Prints numeric, alphabetic, and special characters.
Prints at full speed in decimal form using simultaneous conversion program.
Prints 72 characters in any of 120 character positions on one line, more at reduced speed.
Automatic line spacing or skipping, under control of stored program.

Card reader and card punch:

Reads or punches any 72 of the 80 card columns.
Reading rate - 150 cards per minute.
Punching rate - 100 cards per minute.
Reads or punches cards in standard IBM decimal code at full speed using simultaneous conversion program.
Reads or punches cards in binary form at full speed with 24 words of 36 bits each to a card.

Data in part are from Charles J. Bashe, Lyle R. Johnson, John H. Palmer and Emerson W. Pugh, IBM's Early Computers, published in 1986 by the MIT Press.