The display system is an excellent means for you to see what your computer is doing, but you need help at the other end, too, so that you can communicate with your PC and tell it what to do. Such is the job of the keyboard. Again, with the keyboard, different design variations are possible. Apple Computer demonstrated one technique with its Apple II by making the keyboard part of the computer, both physically and electrically.
IBM also relied on its office experience to tether the keyboard to a cord so that it could be positioned to better suit the user. Although the separate keyboard design is more complex electrically-all the signals from the keyboard must be reduced to a form that can be sent through a narrow cable instead of being directly connected to the computer's circuitry, the flexibility of the separate keyboard design pays off in improving the workplace environment and even enabling the easy substitution and replacement of keyboards-in case of failure or just the need for something new under your fingers.
The keyboard and display system are only examples of the overall IBM philosophy in the original PC. IBM took the best ideas of the machines on the marketplace, refined them, and put them together in a single, clever computer. The bottom line was that the IBM PC was designed around many practical constraints at an almost totally unfocused market. It was almost as if IBM put the machine in stores to see who if anyone, would buy it.
Much to the surprise of everyone, including IBM, people did buy it. Small businesses did. Huge corporations did. PCs sold so quickly that IBM couldn't make them fast enough. The PC touched off a revolution. It spawned several succeeding and more powerful models. Its logical and practical design set the standard for a new industry.
Dozens of manufacturers-from one-man-and-a-soldering-iron garage operations to multi-billion-dollar mega-corporations-created their own versions of the PC, each designed to be as compatible as possible with the IBM original.