The IBM 702 was an early generation tube-based digital computer produced by IBM in the early to mid-1950s. It was the company's response to Remington Rand's UNIVAC—the first mainframe computer to use

magnetic tape Magnetic tape is a medium for magnetic storage made of a thin, magnetizable coating on a long, narrow strip of plastic film. It was developed in Germany in 1928, based on the earlier magnetic wire recording from Denmark. Devices that use magnet ...

s. As these machines were aimed at the business market, they lacked the leading-edge computational power of the

IBM 701 The IBM 701 Electronic Data Processing Machine, known as the Defense Calculator while in development, was IBM’s first commercial scientific computer and its first series production mainframe computer, which was announced to the public on May ...

and ERA 1103, which were favored for scientific computing, weather forecasting, the aircraft industry, and the military and intelligence communities. Within IBM, the 702 was notable for adapting the new technology of

magnetic-core memory Magnetic-core memory was the predominant form of random-access computer memory for 20 years between about 1955 and 1975. Such memory is often just called core memory, or, informally, core. Core memory uses toroids (rings) of a hard magnet ...

for random-access applications. The 702 was announced September 25, 1953, and withdrawn October 1, 1954, but the first production model was not installed until July 1955. It was superseded by the IBM 705.

History

Fourteen 702s were built. The first one was used at IBM. Due to problems with the Williams tubes, the decision was made to switch to

instead. The fourteenth 702 was built using magnetic-core memory, and the others were retrofitted with magnetic-core memory. The successor to the 702 in the 700/7000 series was the IBM 705, which marked the transition to magnetic-core memory.

Overview

The 702 was designed for business data processing. Therefore, the memory of the computer was oriented toward storing characters. The system used electrostatic storage, consisting of 14, 28, 42, 56, or 70 Williams tubes with a capacity of 1000 bits each for the main memory, giving a memory of 2,000 to 10,000 characters of seven bits each (in increments of 2,000 characters), and 14 Williams tubes with a capacity of 512 bits each for the two 512-character accumulators. A complete system included the following units: *IBM 702

Central Processing Unit A central processing unit (CPU), also called a central processor, main processor or just processor, is the electronic circuitry that executes instructions comprising a computer program. The CPU performs basic arithmetic, logic, controlling, a ...

* IBM 712 Card Reader *IBM 756 Card Reader Control Unit * IBM 717 Printer *IBM 757 Printer Control Unit *IBM 722 Card Punch *IBM 758 Card Punch Control Unit * IBM 727 Magnetic Tape Unit *IBM 752 Tape Control Unit *IBM 732 Magnetic Drum Storage Unit Total weight (depending on configuration): about .Weight with only one tape unit:
32,844 lbs - 9,110 lbs + (9,110 lbs / 10) = 23734 + 911 = 24645 lbs
*

References

External links

IBM Archives: 702 Data Processing SystemIBM 702 Documents on bitsavers
{{IBM vacuum tube computers 702 7 0702 Computer-related introductions in 1953 Variable word length computers

History

Overview

See also

References

External links