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The 12-bit PDP-8, produced by Digital Equipment Corporation (DEC), is the first successful commercial minicomputer. DEC introduced it on March 22, 1965, and sold more than 50,000 systems, the most of any computer up to that date.〔(The Digital Equipment Corporation PDP-8 ) by Douglas W. Jones〕〔(PDP-8 1965 ), ''History Wired,'' Smithsonian Institution, accessed February 17, 2015〕 It was the first widely sold computer in the DEC PDP series of computers (the PDP-5 was not originally intended to be a general-purpose computer).〔(【引用サイトリンク】title=PDP-8 Summary of Models and Options )〕 The chief engineer who designed the initial version of the PDP-8 was Edson de Castro, who later founded Data General.〔(The ultimate entrepreneur: the story of Ken Olsen and Digital Equipment Corporation ) entry in Google Books, by Glenn Rifkin, George Harrar, 1988, ISBN 978-1-55958-022-9〕 The earliest PDP-8 model (informally known as a "Straight-8") used diode-transistor logic, packaged on flip chip cards, and was about the size of a small household refrigerator.〔Marshall William McMurran , ''Achieving Accuracy: A Legacy of Computers and Missiles'' Xlibris Corporation, 2009 ISBN 1436381061 page 88〕 This was followed in 1966 by the PDP-8/S, available in desktop and rack-mount models. By using a one-bit serial arithmetic logic unit (ALU) implementation, the PDP-8/S was smaller, less expensive and slower than the original PDP-8. The PDP-8/S was about 20% of the cost and about 10% of the performance of the PDP-8.〔The Rhode Island Computer Museum. ("Digital Equipment PDP-8/S, S/N 517" ).〕 The only mass storage peripheral available for the PDP-8/S was the DF32 disk. Later systems (the PDP-8/I and /L, the PDP-8/E, /F, and /M, and the PDP-8/A) returned to a faster, fully parallel implementation but used much less costly transistor-transistor logic (TTL) MSI logic. Most surviving PDP-8s are from this era. The PDP-8/E is common, and well-regarded because so many types of I/O devices were available for it. It was often configured as a general-purpose computer. In 1975, early personal computers based on inexpensive microprocessors, such as the MITS Altair 8800 and later TRS-80, Apple II and others began to dominate the market for small general purpose computers. The last commercial PDP-8 models in 1979 were called "CMOS-8s" and used custom complementary metal-oxide-semiconductor (CMOS) microprocessors. They were not priced competitively, and the offering failed. The IBM PC in 1981 cemented the doom of the CMOS-8s by making a legitimate, well-supported small microprocessor computer. Intersil sold the integrated circuits commercially through to 1982 as the Intersil 6100 family. By virtue of their CMOS technology they had low power requirements and were used in some embedded military systems. ==Architectural significance== The PDP-8 combined low cost, simplicity, expandability, and careful engineering for value. The greatest historical significance was that the PDP-8's low cost and high volume made a computer available to many new people for many new uses. Its continuing significance is as a historical example of value-engineered computer design. The low complexity brought other costs. It made programming cumbersome, as is seen in the examples in this article and from the discussion of "pages" and "fields". Some ambitious programming projects failed to fit in memory or developed design defects that could not be solved. As design advances reduced the costs of logic and memory, the programmer's time became more important. Subsequent computer designs emphasized ease of programming, typically using a larger and more intuitive instruction set. Eventually, most machine-language programming came to be generated by compilers and report generators. The reduced instruction set computer returned full-circle to the PDP-8's emphasis on a simple instruction set and achieving multiple actions in a single instruction cycle, in order to maximize execution speed, although the newer computers had much longer instruction words. 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「PDP-8」の詳細全文を読む スポンサード リンク
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