In the 1950s,two devices would be invented which would improve the computer field and cause the beginning of the computer revolution. The first of these two devices was the transistor. Invented in 1947 by William Shockley, John Bardeen, and Walter Brattain of Bell Labs, the transistor was fated to oust the days of vacuum tubes in computers, radios, and other electronics.
The vacuum tube, used up to this time in almost all the computers and calculating machines, had been invented by American physicist Lee De Forest in 1906. The vacuum tube worked by using large amounts of electricity to heat a filament inside the tube until it was cherry red. One result of heating this filament up was the release of electrons into the tube, which could be controlled by other elements within the tube. De Forest's original device was a triode, which could control the flow of electrons to a positively charged plate inside the tube. A zero could then be represented by the absence of an electron current to the plate; the presence of a small but detectable current to the plate represented a one.
Vacuum tubes were highly inefficient, required a great deal of space, and needed to be replaced often. Computers such as ENIAC had 18,000 tubes in them and housing all these tubes and cooling the rooms from the heat produced by 18,000 tubes was not cheap.. The transistor promised to solve all of these problems and it did so. Transistors, however, had their problems too. The main problem was that transistors, like other electronic components, needed to be soldered together. As a result, the more complex the circuits became, the more complicated and numerous the connections between the individual transistors and the likelihood of faulty wiring increased.
In 1958, this problem too was solved by Jack St. Clair Kilby of Texas Instruments. He manufactured the first integrated circuit or chip. A chip is really a collection of tiny transistors which are connected together when the transistor is manufactured. Thus, the need for soldering together large numbers of transistors was practically nullified; now only connections were needed to other electronic components. In addition to saving space, the speed of the machine was now increased since there was a diminished distance that the electrons had to follow.
In 1971, Intel released the first microprocessor. The microprocessor was a specialized integrated circuit which was able to process four bits of data at a time. The chip included its own arithmetic logic unit, but a sizable portion of the chip was taken up by the control circuits for organizing the work, which left less room for the data-handling circuitry. Thousands of hackers could now aspire to own their own personal computer. Computers up to this point had been strictly the legion of the military, universities, and very large corporations simply because of their enormous cost for the machine and then maintenance. In 1975, the cover of Popular Electronics featured a story on the "world's first minicomputer kit to rival commercial models....Altair 8800." The Altair, produced by a company called Micro Instrumentation and Telementry Systems (MITS) retailed for $397, which made it easily affordable for the small but growing hacker community.
The Altair was not designed for your computer novice. The kit required assembly by the owner and then it was necessary to write software for the machine since none was yet commercially available. The Altair had a 256 byte memory--about the size of a paragraph, and needed to be coded in machine code- -0s and 1s. The programming was accomplished by manually flipping switches located on the front of the Altair.