CYBER NOTES by Dave Benore
What are computers and where did they come from?
If you stick some numbers into a device, hit some buttons and get an answer, do you have a computer? Nope! You have a calculator. So what makes computers different from calculators? They have a memory and… “But,” you cry, “my calculator has a memory!”
Aha! You didn’t let me finish. Computers have a memory and a stored program. That’s what makes them different from calculators. A stored program is simply a set of instructions that the computer will follow when you put something into it. The instructions are “stored” in the computer’s memory. And they can be easily changed. So where did computers come from? They came from calculators. “Well, how did they do that” you ask. (You did think of asking, didn’t you?)
Go back to ancient times. Rome, Greece, China--they all used a form of abacus. You know, beads on wires. Never saw one? You can actually buy them even now. But I digress. Abacuses were used for counting, adding, and subtracting. Since multiplication and division are simply special ways of adding and subtracting, one could do crude multiplication and division on an abacus. (But it would look exactly like addition and subtraction!)
Fast forward to more modern times. Blaise Pascal, in 1642, made an adding and subtracting machine out of toothed wheels that turned one another. People started getting the idea that mechanical systems could do arithmetic. They were right! (Think of the odometer in your car that keeps adding on miles for you. It uses toothed wheels to do the job.) Some of us may remember the old Friden mechanical adding machines found in every engineering office up into the 1960’s. There were also office adding machines--again mechanical.
Jump to World War II. Remember hearing of the Norden bombsight the US used in its heavy bombers? It was a tightly guarded secret during the war. It was a mechanical computer that used gears (toothed wheels) to compute when to drop bombs, based on knowing the planes speed and altitude, etc. It worked very well. It is a good example of a true computer that is totally mechanical. But the problem with mechanical computers, made up of gears and the like, is that they cannot be easily reprogrammed—given a different set of instructions. It requires changing the gears around, which is hardware. (Remember that term. Hardware means physical things you can hold in your hand.)
As science progressed there was a real need to develop a machine that would do calculations very, very fast, and do many different kinds of calculations. That is, it had to be reprogrammable to do different kinds of problems. So the engineers dreamed up a new idea. Use electrical signals to do the calculations! By using very many switches in a certain pattern, the engineers could add, subtract, even multiply and divide. And if the engineers could easily change the pattern—the instructions--a different problem could be tackled. (The pattern is the program. Since the engineers found a way to easily change the program, the programs were called software, opposite of hardware. Software isn’t physical, it’s instructions. It is held on CDRoms, floppy disks, or your computer’s hard disk.. You cannot “hold” software in your hand. You can only hold what it is recorded on.)
The first real computer used vacuum tubes--(remember those?)--as the electrical switches. It was called ENIAC, for Electronic Numerical Integrator and Computer. It was built at the University of Pennsylvania in 1946! ENIAC was 8 feet high and 78 feet long! It used some 18,000 vacuum tubes and could do 5000 additions per second! (If you remember taking vacuum tubes from your early color TV set to the local drugstore to test them to find the bad one, you might imagine the problem with 18,000 vacuum tubes!)
But hey! Transistors were invented in 1947 and perfected in the 1950’s. They replaced vacuum tubes and were millions of times more reliable. Computers got smaller and cheaper but they were still large and expensive. In the 1960’s, the integrated circuit was invented. This placed many transistors on a small “chip”. Miniaturization had started. Computers got still smaller and cheaper yet.
In the 1970’s, the microprocessor was born—a kind of super-integrated chip. They allowed the first microcomputers to be economically made. Commodore and Apple are two names you might remember. In August of 1981, IBM came out with their personal computer, the “PC”. It was a microcomputer of their own design. Many companies copied IBM’s design over the years, and improved it tremendously. Apple continued to improve their designs also and today also builds a very capable computer.
And that’s where computers came from!
