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8 Chapter 1 Introduction to Computers and Programming
refers to a computer’s memory by itself, the person typically means main memory—the computer’s RAM. When someone refers to a computer’s disk space, the person typically means the capacity of the computer’s hard disk. When someone refers to computer by itself, the person usually means the box that contains the CPU, the main memory, the hard disk drive and its associated hard disk, and the diskette drive. I/O devices, although they’re part of a computer system, are typically not considered to be part of the computer. Instead, they are considered to be peripheral devices because they are on the periphery of the computer. When someone says floppy or floppy disk, they mean a removable diskette.
Why is the term “floppy” used for a diskette? If you’ve got a diskette lying around, cut open the dis- kette’s hard plastic case. You’ll see that the storage media inside is flexible, or floppy. Be aware that in cutting open the diskette case, you’ll destroy the diskette. Make sure the diskette doesn’t contain your homework. We don’t want you to get a bad grade on your homework and tell your teacher “The authors made me do it!”
Pace of Computer Improvements
For as long as memory and CPU components have been around, manufacturers of these devices have been able to improve their products’ performances at a consistently high rate. For example, RAM and hard disk capacities double approximately every two years. CPU speeds also double approximately every two years.
An urban legend is a story that spreads spontaneously in various forms and is popularly believed to be true. The following exchange is a classic Internet urban legend that comments on the rapid pace of com-
1
puter improvements. Although the exchange never took place, the comments, particularly the first one, are
relevant.
At a recent computer expo (COMDEX), Bill Gates reportedly compared the computer industry with the
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auto industry and stated, “If GM had kept up with the technology like the computer industry has, we would all be driving $25.00 cars that got 1,000 miles to the gallon.”
In response to Bill’s comments, General Motors issued a press release stating:
If GM had developed technology like Microsoft, we would all be driving cars with the following characteristics:
1. For no reason whatsoever, your car would crash twice a day.
2. Every time they repainted the lines in the road, you would have to buy a new car.
3. Occasionally your car would die on the freeway for no reason. You would have to pull over to the side of
the road, close all of the windows, shut off the car, restart it, and reopen the windows before you could
continue. For some reason you would simply accept this.
4. Occasionally, executing a maneuver such as a left turn would cause your car to shut down and refuse to
restart, in which case you would have to reinstall the engine.
5. Macintosh would make a car that was powered by the sun, was reliable, five times as fast and twice as
easy to drive—but would run on only five percent of the roads.
6. The oil, water temperature, and alternator warning lights would all be replaced by a single “This Car
Has Performed an Illegal Operation” warning light, and the car would not work.
7. Occasionally, for no reason whatsoever, your car would lock you out and refuse to let you in until you
simultaneously lifted the door handle, turned the key and grabbed hold of the radio antenna.
8. The airbag system would ask “Are you sure?” before deploying.
1 Snopes.com, Rumor Has It, on the Internet at http://www.snopes.com/humor/jokes/autos.asp (visited March 15, 2007).