A computer works one-step at a time. It can add and subtract numbers, compare letters to determine alphabetic sequence, and move and copy numbers and letters. Thereís certainly nothing profound in these operations. Whatís significant is the computerís speed. Measured in units , the time required for computers to execute a basic operation varies from a few microseconds for the smallest machines to 80 nanoseconds or less for the larger ones. Thus, the slowest computers can perform hundreds of thousands of additions in a second while the largest systems can complete many millions.
The benefit of the computerís speed is that we humans are freed to use our time more creatively. Our time dimension has been broaded. We can now often obtain information that could not have been produced at all a few years ago or that could have been prepared only after a great human effort. John Kemeny, former President of Dartmouth College and an author of BASIC, a popular language used to prepare computer programs, has noted that in 1945 it took many people a full year of working around the clock to complete certain calculations at the atomic laboratories at Los Alamos. The same calculations, Kemeny observes, could now be done in one afternoon by a single undergraduate student while sharing a computerís time with dozens of others.
In addition to being very fast, computers are also
very accurate. Itís estimated that you or I would make an error in every
500 to 1,000 operations with a calculator. But the circuits in a
computer require no human intervention between processing operations and
have no mechanical parts to wear and malfunction. These circuits
can perform hundreds of thousands of operations every second and can run
errorless for hours and days at a time. Beyond this, computers also
have built-in, self-checking capabilities that permit them to monitor the
accuracy of their internal operations. If the input data entering
the computer is correct and relevant and if the program of processing instructions
is reliable, then we can expect that the computer generally will produce