Software Gems: The Computer History Museum Historical Source Code Series
Rather than using IBM proprietary components developed for their many other computers, the IBM PC used industry standard commercial parts. That included adopting the Intel 8088 microprocessor as the heart of the computer.
This “outsourcing” attitude extended to the software as well. Although IBM had prodigious internal software development resources, for the new PC they supported only operating systems that they did not themselves write, like CP/M-86 from Digital Research in Pacific Grove CA, and the Pascal-based P-System from the University of California in San Diego. But their favored OS was the newly-written PC DOS, commissioned by IBM from the five-year-old Seattle-based software company Microsoft.