I AM writing this on a personal computer. It cost more than the majority of the world's people earn in a year. Each time I tap a key, I am using more technology than was available to produce all of Shakespeare's works, or Jefferson's, or Thoreau's.Yet such writers spoke across centuries, with nothing but candlelight and pens. While today, with all the ROM and RAM at our disposal, writers are doing well to get out a phrase that is remembered until lunch. What is happening? Does the message - and we who convey it - become less, as the technology of production becomes more? It is a good time to ask. As the newspapers have been reminding us, it is now 10 years since International Business Machines put the first personal computers up for sale. In that short time, these devices have so permeated our lives that it is easy to lose track of the changes they have brought. Mostly, the euphoric view of a high-tech future still holds sway. Soon computers will work by voice, we read. They will be in every home. "The main event is yet to come," gushed a techno-futurist from Silicon Valley to the New York Times. But should we play host? It is time to stop gawking at computers, and start asking whether they are really making life better. The realm I know from experience, writing, gives me suspicions. Recently I read over some articles I wrote back in the typewriter days (circa 1984). The mode of production was, by today's standard, primitive. Yet the writing was no worse than what I turn out now with the help of Toshiba, Panasonic, and the WordPerfect and Microsoft corporations. This seems true generally. There has been no great advance in the quality of writing since computers came. Lincoln scratched out the Gettysburg Address on a scrap of paper. The current chief executive can't come close to that level of eloquence, with all the government computers at his disposal. If writing today isn't any better, it is definitely more expensive. The purchase price of a computer is just the entrance fee. After that come the software upgrades ($100 or so), an extended warranty ($249) - it never seems to end. For all this, the thing will probably be worn out or obsolete in three to five years. An act of production - writing - has become one of consumption; computers do less to serve the writer than to enlist the writer in the service of the economy. For years, the central mission of the American economy has been creating a constant state of need. Cars are built to wear out; the mass media propagates images of physical beauty and wealth to arouse unhappiness and a desire to consume. The computer is the full flower of this process - a perpetual need machine. There is no denying that computers make revising more easy. (A few seconds ago this paragraph was someplace else.) But convenience has a price. Back in the typewriter days, the retyping of whole drafts could coax out the larger rhythms of a piece. The clack of keys worked like the sound of railcars on a track, a kind of soothing percussion for the mind. Computers, by contrast, tempt one to fiddle endlessly with sentences. I used to think harder about what I wrote when fixing it wasn't so easy. But the real problem is the way computers always call attention to themselves. I never had to think about the old Royal manual. Change the ribbon. Get it cleaned every few years. That was all it demanded. This computer, by contrast, is a petulant child that requires constant attention. I have spent hours futzing with manuals and the "config. sys" file. All this is a diversion. Whether you write with a Mac or a No. 2 pencil, the task is pretty much the same. It is work not on an instrument but on one's self. "The best that you can write will be the best you are," Thoreau said, adding that his aim was to speak "like a man in a waking moment to men in their waking moments." He wrote that with a pen. I doubt that a software upgrade would have helped him say it better. Had he been vexed by hard-disc failures, he probably wouldn't have been able to say it at all.