The History of Microprocessors
The history of microprocessors can be said to begin after the era of mainframes and microcomputers which dominated 1960’s computing. Since 1947, transistors had been employed in a number of different industries, and in the later 1960’s they had made their way into microcomputers in the form of simple integrated circuits. M.E. Hoff, who had been working at Intel producing memory chips for mainframes as well as chips for other electronic devices, decided that he could significantly improve on some of the calculator designs that Intel had been selling. He began to incorporate more and more functions into smaller amounts of hardware, in an effort to simplify what he felt were overly complicated systems. In partnership with Fredrico Faggin, much of this combined logic was finally crammed into a single chip which was capable of being programmed. Consisting of 2,000 transistors, it was known as the 4004, the world’s first true microprocessor.
Intel purchased the rights to this chip, which it had developed for a client named Busicom, and set out to refine the microprocessor and introduce it to other applications. In just two years, the company was able to double the capacity of the 4-bit chip to 8-bits, renaming it the 8008 and leading to the groundbreaking 8088 processor being released a short time later in 1974. The 8088 had a separate data and address bus and 64K of memory, which was a huge advance at the time for any computer, mainframe or otherwise. Intel’s 8088 chip was soon sharing the market with a chip manufactured by Motorola known as the 6800, which was also an 8-bit microprocessor. These two ‘lineages’ would dominate microprocessor development for the next 30 years.
With the 8088 and the 6800 on the scene, a number of ‘copycat’ competitors began to appear, hawking chips which had architectural differences from each of the mainstays but which were for the most part capable of executing the same code. This meant that less expensive chips could interact with programs that had originally been written for Intel or Motorola hardware, allowing these smaller companies to tap into a pre-existing customer base instead of having to develop their own. The idea of compatibility with other hardware systems as opposed to pursuing a completely proprietary path would become an important feature of microprocessor design from the mid-1970’s on.
The number of transistors which could be packed onto a single microprocessor continued to grow as manufacturing technologies and heat management solutions improved. As a result, microprocessors grew more and more powerful, setting off a computational arms race of sorts to see which company’s products could execute the most number of instructions in the least amount of time. Intel, still a dominant chipmaker in the 1980’s produced a 16-bit chip dubbed the 8086, while Motorola retaliated with the 68000 around the same time period. Whereas Intel maintain compatibility with previous chips in their new 16-bit processor – paying a price in terms of memory access as a result – Motorola started straight from scratch, avoiding many of the pitfalls associated with legacy designs. IBM, Compaq, and other ‘clone’ manufacturers would stick with Intel for the long haul, while Apple and Amiga released machines featuring the Motorola microprocessor.
In the 1990’s, Intel’s architecture would be combined with Motorola’s thanks to the development of the PowerPC. However, it would not be enough to displace Intel’s designs from the marketplace, and the California company remains the driving force in microprocessor development both in America and around the world. The x86 architecture has proven to be one of the longest-standing contributions to microprocessor design every made.
