The team that designed the IBM Personal Computer faced a very tight deadline—they had to design and produce a completely new microcomputer within just one year’s time. To accomplish this task, they had to take a new approach to building a computer.
Piecing it together
To save time, the development team decided to build the new machine mostly from existing components. About half of the system was from the IBM System/23 Datamaster, which was released just one month before the PC. Components such as the expansion bus, display, monitors, BIOS, floppy interface and keyboard were shared between the Datamaster and the PC. The rest of the system mostly comprised “off-the-shelf” components, including the floppy drives, software, BASIC in ROM and the Intel processor.
Because the PC was designed using readily available components, it was easy to replicate. The only proprietary component of the PC was the BIOS (Basic Input/Output System), but soon other companies determined they could reverse-engineer the IBM BIOS and then write their own BIOS using clean room design. As more and more software was developed for the IBM PC, other computer makers began making machines that could use the same programs, spawning the proliferation of IBM-compatible computers, which are the ascendants of the majority of microcomputers on the market today.
The birth of a new industry
At the time of its release, Don Estridge published the specifications for the IBM Personal Computer, allowing other manufacturers to produce and sell peripheral components and compatible software. With this act, the software industry was born. Microsoft supplied the operating system, PC-DOS, for the IBM PC, and sold a version called MS-DOS to other computer makers, including manufacturers of IBM-compatible computers. In addition, Microsoft and other software companies began developing application software for word processing, accounting, project management, computer-aided design, gaming and much more. Today, the software industry is a US$300,000,000,000 industry.