IBM model 5150 System Unit with integral twin 5 1/4 inch disk drives, made by IBM, Greenock, Scotland, 1983. 64K memory, single-sided double density 5 1/4 40 tpi 106K drives

IBM model 5150 System Unit with integral twin 5 1/4 inch disk drives, made by IBM, Greenock, Scotland, 1983.

The IBM Personal Computer System was introduced in early 1981, at a time when IBM was the world's largest mainframe computer manufacturer. It was the catalyst for the personal computer industry. Such was IBM's reputation that 200,000 of the PCs were sold in the first year. As a result it set a standard by which every other computer company was to be measured. The microcomputer market had grown from its original appeal to enthusiasts and hobbyists to a potential billion-dollar industry. The IBM PC used the Intel 8088 microprocessor, therefore also contributing to Intel's growing success. The machine used magnetic tape to load data and featured an optional floppy disk drive. The hard drive did not make an appearance until the release of IBM's XT machine in 1983.