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A 1989 look at what computers are and how they work, without any jargon.
  technofile
Al Fasoldt's reviews and commentaries, continuously available online since 1983

Gobledegook demystified: A no-jargon guide to computers


By Al Fasoldt
Copyright © 1989, The Syracuse Newspapers
   It's all mumbo-jumbo.
   It's techno-babble. It's impossible to understand.
   If that's how you feel when someone assaults your ears with the jargon of computers, cheer up. I've got good news for you.
   You're right. It is, indeed, mumbo-jumbo. And it doesn't have to be.
   You have enough things on your mind these days. There's no reason you should have to learn a whole new language just to write a few notes on your computer or balance this month's outgo against last month's income.
   So here's a translator's guide to computer gobbleygook. These descriptions aren't meant to be technically precise, but they're at least easy to understand.
   First, computers come in three basic types. The ones that can fit on your desk or on your lap are personal computers. The ones that are as big as vending machines are business computers. And the ones that are as big as an entire office are mainframe computers.
   Unfortunately for your sanity, the "official" names for the three types are confusing. Don't read the next paragraph unless you're willing to gamble on logic.
   Big computers, the mainframes, are sometimes referred to as plain computers. Medium-size ones, which I call business computers, are one size smaller, so they're sometimes called minicomputers. Personal computers are one size smaller than that, so they're sometimes called microcomputers.
   Computers of any size need to store what they work with. You have closets and drawers to store your own stuff; they have disk drives and memory chips. Computers store things for a long time on disks and for a short time on chips.
   What they store is, of course, data. You can't see a single datum (you can't even make sense of such a strange Latin word), but you can tell the computer to do all sorts of jobs with big groups of data.
   You can think of data as raw numbers. A computer doesn't deal with anything else. It doesn't use words (not even when you are using a word processor to write a letter to Aunt Milly), and it doesn't use pictures (not even when it shows you a trash can on the screen).
   Everything that happens in the computer happens with numbers. For example, words are actually made up of numbers inside the computer, with a separate digit for each letter. The word "computer" is made up of eight numbers, and each time you type "c-o-m-p-u-t-e-r" on your computer keyboard all you are really doing is telling your PC to put those eight numbers away in storage somewhere.
   Usually, they're tucked away on a chip. But if you press the proper keys or click your mouse button just the right way, your computer will also stick those eight numbers onto a disk. That's handy if your computer gets turned off accidentally, since the numbers on the disk are more or less permanent. But now it's time to point out what computer experts know and the rest of us are still learning. When somebody who is talking about computers says something like "more or less," you can bet that there's less to the "more" and more to the "less." In other words, numbers that are stored on disks are less permanent than you might expect.
   That's because disks are made to be magnetized. That's how the computer stores data on them. Inside the computer's disk drive, a tiny magnet goes on and off many times a second while the disk spins underneath it. That's how recording works. It's also called "writing" the data. If the magnet hovers over the same area later, the disk, in turn, makes little on-and-off pulses in the magnet. That's called playback, or "reading" the data. This works amazingly well -- mostly because it's so easy to magnetize the disk. That's the "more" that we talked about above. The "less" comes from the same fact. Since disks can be magnetized easy, they can be re-magnetized easily -- by TV picture tubes, computer monitors, electric motors and all sorts of other devices around the house and around the office.
   So make sure you keep your disks away from anything electric or mechanical. Another way that disks can turn out to be less reliable has to do with the precise order of all the magnetic patterns on the disk. They all represent numbers, of course, since that's the only thing that the computer can work with. And some of those numbers are more important than others. The ones that rule the roost are part of a little map that the computer writes so it can find where all the rest of the numbers are.
   This map, appropriately enough, is called a disk directory. Every time the computer wants to take some numbers out of storage or add some new ones, it takes a look at the map first. Here's where everything gets tricky. If you and I were in charge of storing these numbers in a file cabinet, we'd sort them first and put all the related ones together. We'd put a label called "Letters" on one file drawer and then take an empty folder and mark it "Letters to Millie." We'd stick that folder in the proper drawer. Then all the letters we wrote to Aunt Millie would be in that one place.
   But computers aren't so neat and logical. In order to do things quickly, the computer simply tosses stuff anywhere it wants. Instead of filing that letter to Aunt Millie under the computer equivalent of a file folder called "Letters to Millie," the computer puts one sentence in one place, one sentence in another. If you could look at what the computer put on the disk, starting at the beginning and reading it to the end, you might see nothing but scattered words and phrases. The last line of your letter -- "P.S., the cat is going to have kittens" -- might even be stored before the "Dear Millie" part.
   There's a madness in this method, but it does work -- but only if the map, called the disk directory, is accurate. And that means that every number in that directory has to be exactly right. The numbers can't be almost right or somewhat right. They have to be dead on. Think of the disk directory's numbers the way you think of your paycheck. The numbers "2," "5" and "0" are the same as the numbers "0," "2" and "5" -- but if they aren't in the same order they won't pay your bills.
   The computer is just as finicky as you'd be if your check came through with a few digits transposed. At least you'd be able to find the payroll department and make a stink; the computer just loses track of where the other numbers are and can't find anything. Your letter to Millie could end up being a recipe for duck soup. Or a jumble of crazy letters and symbols.
   So how do you guard against this problem? It's easy, actually. Here are two rules:
  • Never take the disk out of the disk drive while the little red or amber light is on.
  • Never switch disks when a program is running unless something you see on the screen tells you to.

   The first rule is very, very important. The light on the disk drive goes on every time the computer is putting numbers on the disk or reading them off the disk. It puts the numbers on in two steps -- first, by writing down the numbers themselves (in any old order, as we just diskussed), and then by writing down where it put those numbers in the map called the disk directory. If you pull out the disk while this is going on, the computer can lose track of that map. Like an old prospector who knows there's gold in them thar hills but can't find the map he made years ago, you'll know there's something you need on that disk but you won't be able to find it.
   The second rule is especially important if you have a computer with only one disk drive. Lots of times you'll have to take one disk out and put another one in just to run the computer properly. But never, ever (say this to yourself three times) swap one disk for another unless you are told to do so. And even then, do it only when you see very clear instructions on the screen.