Tuesday, August 25, 2009


History Further information: History of general purpose CPUs
First types
The 4004 with cover removed (left) and as actually used (right).
Three projects arguably delivered a complete microprocessor at about the same time, namely Intel's 4004, the Texas Instruments (TI) TMS 1000, and Garrett AiResearch's Central Air Data Computer (CADC). Intel's 4004 is considered the first microprocesor.[4][5] This first microprocessor cost in the thousands of dollars.[6] The first known advertisement for the 4004 is dated back to November 1971; it appeared in Electronic News. [7] The project that produced Intel's first known microprocessor originated in 1969, when Busicom, a Japanese calculator manufacturer, asked Intel to build a chip set for high-performance desktop calculators. Busicom's original design called for a dozen different logic and memory chips. Ted Hoff, the Intel engineer assigned to the project, believed the design was not cost effective. His solution was to simplify the design and produce a programmable processor capable of creating a set of complex special-purpose calculator chips. Together with Masatoshi Shima and Federico Faggin, later the founder of Zilog, Hoff came up with a four-chip design; a ROM for custom application programs, a RAM for processing data, an I/O device, and an unnamed 4-bit central processing unit which would become known as a "microprocessor." [8] The Smithsonian Institution says TI engineers Gary Boone and Michael Cochran succeeded in creating the first microcontroller (also called a microcomputer) in 1971. The result of their work was the TMS 1000 which went commercial in 1974. [9] Ray Holt, a graduate of California Polytechnical University in 1968, began his computer design career with the F14 CADC. The central air data computer was shrouded in secrecy for over 30 years from its creation (the year being 1968), it was not publicly known until 1998 at which time, at the request of Mr. Ray Holt, the US Navy allowed the documents into the public domain. Since then many debates have argued that this was, in fact, the first microprocessor. [10] The scientific papers and literature published around 1971 reveal that the MP944 digital processor used for the F-14 Tomcat aircraft of the US Navy qualifies as the “first microprocessor”. Although interesting, it was not a single-chip processor, and was not general purpose – it was more like a set of parallel building blocks you could use to make a special-purpose DSP form. It indicates that today’s industry theme of converging DSP-microcontroller architectures was started in 1971. [11] This convergence of DSP and microcontroller architectures is know as a Digital Signal Controller
In 1968, Garrett AiResearch, with designer Ray Holt and Steve Geller, were invited to produce a digital computer to compete with electromechanical systems then under development for the main flight control computer in the US Navy's new F-14 Tomcat fighter. The design was complete by 1970, and used a MOS-based chipset as the core CPU. The design was significantly (approximately 20 times) smaller and much more reliable than the mechanical systems it competed against, and was used in all of the early Tomcat models. This system contained a "a 20-bit, pipelined, parallel multi-microprocessor". However, the system was considered so advanced that the Navy refused to allow publication of the design until 1997. For this reason the CADC, and the MP944 chipset it used, are fairly unknown even today. (see First Microprocessor Chip Set.) TI developed the 4-bit TMS 1000, and stressed pre-programmed embedded applications, introducing a version called the TMS1802NC on September 17, 1971, which implemented a calculator on a chip. The Intel chip was the 4-bit 4004, released on November 15, 1971, developed by Federico Faggin and Ted Hoff. The manager of the design team was Leslie L. Vadász.
TI filed for the patent on the microprocessor. Gary Boone was awarded U.S. Patent 3,757,306 for the single-chip microprocessor architecture on September 4, 1973. It may never be known which company actually had the first working microprocessor running on the lab bench. In both 1971 and 1976, Intel and TI entered into broad patent cross-licensing agreements, with Intel paying royalties to TI for the microprocessor patent. A nice history of these events is contained in court documentation from a legal dispute between Cyrix and Intel, with TI as intervenor and owner of the microprocessor patent.
Interestingly, a third party (Gilbert Hyatt) was awarded a patent which might cover the "microprocessor". See a webpage claiming an invention pre-dating both TI and Intel, describing a "microcontroller". According to a rebuttal and a commentary, the patent was later invalidated, but not before substantial royalties were paid out.
A computer-on-a-chip is a variation of a microprocessor which combines the microprocessor core (CPU), some memory, and I/O (input/output) lines, all on one chip.It is also called as micro-controller. The computer-on-a-chip patent, called the "microcomputer patent" at the time, U.S. Patent 4,074,351, was awarded to Gary Boone and Michael J. Cochran of TI. Aside from this patent, the standard meaning of microcomputer is a computer using one or more microprocessors as its CPU(s), while the concept defined in the patent is perhaps more akin to a microcontroller.
According to A History of Modern Computing, (MIT Press), pp. 220–21, Intel entered into a contract with Computer Terminals Corporation, later called Datapoint, of San Antonio TX, for a chip for a terminal they were designing. Datapoint later decided not to use the chip, and Intel marketed it as the 8008 in April, 1972. This was the world's first 8-bit microprocessor. It was the basis for the famous "Mark-8" computer kit advertised in the magazine Radio-Electronics in 1974. The 8008 and its successor, the world-famous 8080, opened up the microprocessor component marketplace.

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