Microprocessor History and Evolution
The first microprocessor chip ever invented is regarded to be the 4004, which Intel first sold to Busicom in February 1971 for use in the latter's calculator. The 4004 was pitifully slow and simple by today's standards: It had only 2,300 transistors and ran at a pedestrian 750 KHz (that's 0.000075 GHz). Over the next five years, Intel updated the 4004 chip with the 8008, the 4040, the 8080, and then the 8086, which is still in use today (albeit heavily modified and updated). The 4004 microprocessor was simple enough that you could actually see the transistors and wires, and even a tiny logo in the (enlarged) photograph shown in Figure 6.2.
Figure 6.2. This photograph of the Intel 4004 silicon chip shows the microprocessor's transistors laid out on a rectangular chip. The wires at the edge of the chip connect the silicon to the chip's package. A small Intel logo can be seen in the lower right corner. The actual size of this chip was 12 mm2, or about one-eighth of an inch on a side. Courtesy of Intel Corporation. Used with permission.
At about the same time Intel's 4004 chip debuted, Texas Instruments released its TMC1795 chip. It, too, led to other better chips throughout the early 1970s, but the family eventually died off. Rockwell, RCA, Data General, MOS Technology, Motorola, and other companies also entered the nascent microprocessor market during this period, although few of those companies are still active (or even in existence) today.
The first microprocessors were not created for computers. The very idea was ludicrous in the 1970s, like making rockets in your garage and selling them to NASA. Instead, the first microprocessors were intended for very humble tasks such as running early digital calculators. (Digital calculators existed before 1971, but they used many separate logic chips rather than a single programmable microprocessor chip.)
Around 1980, both Intel and Motorola radically redesigned their microprocessors and came up with the i432 chip and the 68000 chip, respectively. Motorola's new processor was a success but Intel's i432 failed miserably. Although it was a fine design from an engineering perspective, it wasn't successful in the market. Intel quickly resurrected one of its older processors, the 8086, and freshened it up to create the 80186 and the 80286. Also about this time, a small IBM facility in Boca Raton, Florida, selected Intel's 8088 processor (yet another variation on the 8086 chip) to use in its Model 5150 Personal Computer: the first IBM PC. That single decision eventually made Intel the most profitable semiconductor maker in the world as it rode wave after wave of personal computers patterned after IBM's machines.
Motorola and Intel have extended, enhanced, and enlarged their two chip families many times over the years. Intel is still at it: The 386, 486, Pentium I, II, III, and 4 are all direct descendants of the original 4004 microprocessor, circa 1971. Motorola let its 68000 dynasty peter out in the mid-1990s, making another radical redesign to a new chip family called PowerPC.
The 1980s saw a number of old microprocessor companies drop out and new ones join in. National Semiconductor, Western Electric, Digital Equipment Corporation (DEC), Fairchild, Inmos, and others all joined the fray. This decade also saw the rise of the RISC design philosophy from the University of California at Berkeley and at Stanford University, located just across San Francisco Bay from each other. Berkeley's RISC-I and RISC-II chips eventually metamorphosed into Sun Microsystems's SPARC processors, which are still used today. Stanford's MIPS project begat MIPS Computer Systems, later Silicon Graphics.
This period also saw the rise of the x86 clones like AMD, Centaur, Cyrix, NexGen, Rise, Transmeta, UMC, and others too numerous to mention. Intel was enjoying such a bonanza as the PC market skyrocketed that it was inevitable the company would attract imitators. Throughout the late 1980s and early 1990s several companies did their level best to clone, or copy (legally or not) the Intel chip that was used in almost all PCs of the period. These were collectively called x86 processors because Intel's model numbers all ended with the digits 86 (i.e., 8086, 80386, 80486, etc.). Most of these x86 clones were quite good—some were even technically superior to Intel's own processors. However, the clone makers never made a significant dent in Intel's PC-processor monopoly (or, as the U.S. Federal Trade Commission called it in a 1999 consent decree, a “dominant market share,” narrowly avoiding the dreaded and legally binding M-word). Most of the clone makers eventually went out of business, unable to compete against Intel's vast legal, financial, and marketing resources.
The later 1990s saw fewer new companies enter the microprocessor market and some old ones drop off. Cyrix, Centaur, and NexGen were absorbed by other companies, Rise and UMC exited the market, and Hewlett-Packard abandoned its own PA-RISC processor design and began collaborating with Intel on a project code-named Tahoe that would eventually become IA-64 (Itanium). Digital's ultra-fast Alpha processors pegged out in 2001, after leading the performance race for nearly 10 years.
Strangely, nearly all the world's significant microprocessors have come from American companies. Although the European and Japanese semiconductor companies were robust, healthy, and active, very few of them ever introduced a successful microprocessor. Some exceptions were the ARM processors (from England) and the V800 and SuperH families (from Japan). Despite the fact that England and Japan were both leaders in computer science and design, neither country made much of a dent in microprocessors.