PC System Design Guide

They were aimed at helping manufacturers provide hardware that made the best use of the capabilities of the Microsoft Windows operating system, and to simplify setup and use of such computers.

Every part of a standard computer and the most common kinds of peripheral devices are defined with specific requirements.

Some "legacy" items such as ISA expansion slots and device dependence on MS-DOS are forbidden entirely, while others are merely strongly discouraged.

"[2] Perhaps the most end-user visible and lasting impact of PC 99 was that it introduced a color code for the various standard types of plugs and connectors used on PCs.

This color code was gradually adopted by almost all PC and motherboard manufacturers.