tplace. The Apple II had 16K bytes of RAM and 16K bytes of ROM; Commodore Business Machines' Personal Electronic Transactor (PET) included 4K RAM and 14K ROM; and the TRS-80 had 4K RAM and 4K ROM. Also in 1977, the Central Program for Microprocessors (CP/M) operating system was developed by Digital Research and Gary Kildall. From its introduction until 1980, CP/M was used in most PCs, but even that did not guarantee that a program or document could be written on one machine and read on another because each manufacturer used different floppy disk drives. Apple introduced the floppy disk drive in 1978, allowing Apple II users to store data on something other than the cumbersome and unreliable tape cassettes that had been used up to that point. But despite the popularity of the three PCs, non-computer people still saw little reason to buy an expensive calculator when there were other ways to do the same things. In 1979, that all changed. When VisiCalc was introduced for the Apple II, non-computer people suddenly saw a reason to buy a computer. VisiCalc, a spreadsheet program created by Dan Bricklin and Bob Frankston, allowed people to change one number in a budget and watch the effect it had on the entire budget. It was something new and valuable that could only be done with a computer. For thousands of people, the toy, the computer few could find a use for, had been transformed into a device that could actually do something worthwhile. Microprocessors and high-tech gadgets were gradually worming their way into people's lives. In 1978, Sony introduced the Beta format video cassette recorder, and a year later the VHS video recorder and the Sony Walkman. And to remind everyone of how far we had to go, Star Trek: The Motion Picture came to theaters in 1979. The Sinclair ZX-80 PC, which hit the market in 1980, used the same Z-80 chip as Commodore's PET and the Tandy TRS-80. The ZX-80 had 1K ...
