These innovations made it cheaper and easier to manufacture computers than ever before. As a result, the small, relatively inexpensive “microcomputer”–soon known as the “personal computer”–was born. In 1974, for instance, a company called Micro Instrumentation and Telemetry Systems (MITS) introduced a mail-order build-it-yourself computer kit called the Altair. Compared to earlier microcomputers, the Altair was a huge success: Thousands of people bought the $400 kit. However, it really did not do much. It had no keyboard and no screen, and its output was just a bank of flashing lights. Users input data by flipping toggle switches.
In 1975, MITS hired a pair of Harvard students named Paul G. Allen and Bill Gates to adapt the BASIC programming language for the Altair. The software made the computer easier to use, and it was a hit. In April 1975 the two young programmers took the money they made from “Altair BASIC” and formed a company of their own—Microsoft—that soon became an empire.
The year after Gates and Allen started Microsoft, two engineers in the Homebrew Computer Club in Silicon Valley named Steve Jobs and Stephen Wozniak built a homemade computer that would likewise change the world. This computer, called the Apple I, was more sophisticated than the Altair: It had more memory, a cheaper microprocessor and a monitor with a screen. In April 1977, Jobs and Wozniak introduced the Apple II, which had a keyboard and a color screen. Also, users could store their data on an external cassette tape. (Apple soon swapped those tapes for floppy disks.) To make the Apple II as useful as possible, the company encouraged programmers to create “applications” for it. For example, a spreadsheet program called VisiCalc made the Apple a practical tool for all kinds of people (and businesses)–not just hobbyists.