The IBM 608 Transistor Calculator, a plugboard-programmable unit, was the first IBM product to use

transistor upright=1.4, gate (G), body (B), source (S) and drain (D) terminals. The gate is separated from the body by an insulating layer (pink). A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch e ...

circuits without any

vacuum tube A vacuum tube, electron tube, valve (British usage), or tube (North America), is a device that controls electric current flow in a high vacuum between electrodes to which an electric voltage, potential difference has been applied. The type kn ...

s and is believed to be the world's first all-transistorized calculator to be manufactured for the commercial market. Announced in April 1955,IBM Archives: IBM 608 calculator
/ref> it was released in December 1957. The 608 was withdrawn from marketing in April 1959.

History

The chief designer of the circuits used in the IBM 608 was Robert A. Henle, who later oversaw the development of

emitter-coupled logic In electronics, emitter-coupled logic (ECL) is a high-speed integrated circuit bipolar transistor logic family. ECL uses an overdriven bipolar junction transistor (BJT) differential amplifier with single-ended input and limited emitter current to ...

(ECL) class of circuits. The development of the 608 was preceded by the prototyping of an experimental all-transistor version of the

604 __NOTOC__ Year 604 (Roman numerals, DCIV) was a leap year starting on Wednesday (link will display the full calendar) of the Julian calendar. The denomination 604 for this year has been used since the early medieval period, when the Anno Domini ...

. Although this was built and demonstrated in October 1954, it was not commercialized. To spur the adoption of transistor technology, shortly before the first IBM 608 shipped, Tom Watson directed that a date be set after which no new vacuum-tube-based products would be released. This decision constrained IBM product managers, who otherwise had the latitude to select components for their products, to make the move to transistors. As a result, the successor to the

IBM 650 The IBM 650 Magnetic Drum Data-Processing Machine is an early digital computer produced by IBM in the mid-1950s. It was the first mass produced computer in the world. Almost 2,000 systems were produced, the last in 1962, and it was the first ...

used transistors, and it became the

IBM 7070 IBM 7070 was a decimal-architecture intermediate data-processing system that was introduced by IBM in 1958. It was part of the IBM 700/7000 series, and was based on discrete transistors rather than the vacuum tubes of the 1950s. It was the compa ...

—the company's first transistorized

stored-program computer A stored-program computer is a computer that stores program instructions in electronically or optically accessible memory. This contrasts with systems that stored the program instructions with plugboards or similar mechanisms. The definition i ...

. It was similar in nature of operation to the vacuum-tube IBM 604, which had been introduced a decade earlier. Although the 608 outpaced its immediate predecessor, the IBM 607 by a factor of 2.5, it was soon rendered obsolete by newer IBM products and only a few dozen were ever delivered.

Overview

The 608 contained more than 3,000

germanium Germanium is a chemical element with the symbol Ge and atomic number 32. It is lustrous, hard-brittle, grayish-white and similar in appearance to silicon. It is a metalloid in the carbon group that is chemically similar to its group neighbors s ...

s. The use of transistors was a significant departure from the previous IBM calculators of this line. The 608's transistors made possible a 50 percent reduction in physical size and a 90 percent reduction in power requirements over comparable vacuum tube models. The 608 also used

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 magneti ...

, but was still programmed using a control panel. The main memory of the 608 could store 40 nine-digit numbers, and it had an 18-digit accumulator.Frank da Cruz
The IBM 608 Calculator
Columbia University Computing History In raw speed terms, it could perform 4,500 additions per second, it could multiply two nine-digit numbers, yielding an 18-digit result in 11 milliseconds, and it could divide an 18-digit number by a nine-digit number to produce the nine-digit quotient in 13 milliseconds. The 608 could handle 80 program steps. The 608 was supplied with a type 535 card reader/punch which had its own control plugboard.

References

IBM Transistor Calculator Type 608 Manual of Operation – Preliminary Edition
{{reflist, 25em

External links

IBM transistorized computers 608 Programmable calculators Computer-related introductions in 1957

History

Overview

See also

References

External links