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The IBM 608 was the first IBM product to use transistor circuits without any vacuum tubes and is believed to be the world's first all-transistorized calculator to be manufactured for the commercial market. The 608 contained more than 3,000 germanium transistors. Announced in April 1955,〔(IBM Archives: IBM 608 calculator )〕 it was released in December 1957. 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. The 608 was withdrawn from marketing in April 1959.〔 The use of transistors was a significant departure from the previous IBM calculators of this line. The 608 also used magnetic core memory, 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.〔 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 used transistors, and it became the IBM 7070—the company's first transistorized stored-program computer.〔 The chief designer of the circuits used in the IBM 608 was Robert A. Henle, who later oversaw the development of emitter-coupled logic (ECL) class of circuits. The development of the 608 was preceded by the prototyping of an experimental all-transistor version of the 604. Although this was built and demonstrated in October 1954, it was not commercialized.〔 == See also == * (IBM Transistor Calculator Type 608 Manual of Operation – Preliminary Edition ) * Unit record equipment * History of IBM 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「IBM 608」の詳細全文を読む スポンサード リンク
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