12th August 1981: IBM announces the release of the 5150, the first IBM Personal Computer

IBM, which was an established manufacturer of business computer systems, sought to develop a microcomputer to enter the competitive personal computer market. The resulting IBM 5150 was developed in just over a year by a team based in Boca Raton, Florida. Known internally as “Project Chess,” it was led by Don Estridge who opted to use largely off-the-shelf components and a third-party operating system to accelerate development and reduce costs.

The IBM PC featured an Intel 8088 microprocessor running at 4.77 MHz, 16 kilobytes of RAM (expandable to 256 KB), and used cassette tape or 5.25-inch floppy disks for storage. The machine could be connected to a standard television or a dedicated IBM monochrome or colour monitor, and was initially priced at $1,565.

IBM partnered with a small software company, Microsoft, to supply the PC-DOS operating system. While Microsoft retained the rights to license the software to other manufacturers, IBM also encouraged third-party developers to create software for the PC that included word processing, spreadsheet, and database software. This openness helped foster a wide ecosystem of software and peripherals, making the platform attractive to business users and hobbyists alike.

The IBM PC quickly became a commercial success and a standard in the emerging personal computer industry. Its open architecture allowed other manufacturers to produce “IBM-compatible” machines which helped to establish a broad market based on the IBM model, further accelerating the spread of personal computing.