Over time, a rule has emerged about computer devices: the general purpose computer will replace special purpose devices.
For example: we have had calculators based on a computer chip since the 1970's. Today, very few people buy calculators, because they have calculator apps built in to their telephone or tablet or other portable general computer device.
In the late 1970's and early 1980's, word-processing machines were a big market. They were driven out of business by much poorer, and much, much less expensive programs that ran on IBM PCs.
Price plus convenience enables the general computer to wipe out many special purpose devices. But there are exceptions:
- Highly specialized user interface needs: there are plenty of genuine guitars out there. A computer keyboard, or perhaps a music keyboard, plus a general computer, can replace a guitar, but not very well. Your hands can do all sorts of things with a guitar that no one has learned to emulate with a real-time standard computer interface. And in a live performance, a guitar is a show-piece.
- Convenience: You might need quick access to your special device. You may not be happy, say, using your phone and switching contexts to your calculator app, every time you need it.
- Hardware specialization: There are situations where you require a device to have really unusual inputs and outputs. A violin; a mixing panel; an air traffic control seat.
Highly specialized needs prevent a general purpose computer from swallowing up a specialized device. Now, why do I have so many rechargeable, mostly computerized, devices? (See yesterday's blog post for the list, and tomorrow's post for the answer.)