Tucson, Ariz. — A ''byte'' (pronounced ''bite'') is a computer term meaning ''a unit of information for processing.'' This particular byte of knowledge seems out of place on a sunny Arizona spring afternoon in the playground of Mary Moppets Day Care Center, as about 15 merry moppets enjoy recess. But inside the front door, tacked onto a bulletin board with the announcements and crepe-paper hearts, is the sign: Small Bytes Computer School.
Stepping carefully around tiny tables, blocks, and napping babies, a smiling day-care worker leads a visitor to a closed, unmarked door at the rear of the nursery. One the other side, like spy headquarters in a James Bond thriller, is another world, filled with fluorescent light and the steady hum of computers.
In six large, black desk chairs kneel six toddlers, their hands hovering over the keyboards of six computers, choosing and stabbing at letters with a hesitant but definite purpose. ''I got it!'' yodels a frail four-year-old whose cowboy boot has slipped off in his concentration. On the multicolored screen in front of him appears not a secret formula but a blue rocket ship. Satisfied, he rocks back and forth in his chair as next a blond 31/2-year-old, then a pigtailed four-year-old, also announce their triumphs. ''Teacher! Teacher! Look at mine!''
With infinite calm and patience, teacher Kathy Buchheit moves from terminal to terminal, praising, offering guidance, correcting mistakes. There are very few of the latter. For although none of these preschoolers can officially read yet, all have mastered the computer keyboard and the sequence of steps necessary for basic computer programming.
Greg Hudson, founder of the school, ambles through. He has no extensive training in computers or education; in fact, he hasn't even finished college. A science and technology buff, Mr. Hudson has always been fascinated by the ''hows and whys'' of learning. ''Computers are a wide-open field,'' he says. ''Degrees aren't important - experience is.'' Convinced that computers offer a unique way to learn - especially for the very young - he borrowed money for equipment and struck a deal with Mary Moppets for space in the back. Next he hired Miss Buchheit, who was looking for a way to combine her degrees in education and computer science, and Small Bytes was born, now only a few years younger than most of its students.
''Kids need to learn that computers are tools they can use, an extension of their minds the way a shovel is an extension of their arms,'' Hudson explains. ''Computers can make complicated concepts interesting - kids can 'see' them instead of just reading or hearing about it. I can see a time when the way we absorb information will be completely different, melding visual effects with reading.''
And, Hudson insists, ''Kids need to know computers. One person can suddenly gain a lot of clout, a lot of power, just by drawing on the talents of a computer.''
Most of Small Bytes' 60 students come from middle class families, who pay $4 a lesson for twice-weekly sessions. Students range in age from 31/2 to 16, with the average age being 4 or 5. Although the school only began in December, Small Bytes is already opening a second school across town to satisfy demand for the classes.
Henrietta Hatfield, 31/2, runs eagerly toward a computer terminal as her mother drops her off for class. ''She loves this,'' Mary Hatfield says proudly. ''The computer is a fascinating instrument with no limit except her own imagination. But up till now there's been no place except some game room where she had access to them. We don't want her in game rooms - we want her to learn what computers are for.''
At the terminal, Henrietta is busily turning boxes blue and changing planes into trucks. ''We're really thrilled at the changes in her since she's started here,'' Mrs. Hatfield continues. ''She's more perceptive, details mean more, her logic and reasoning have tremendously increased. I'm not saying she's a unique little girl. All children have these potentials, if they're given the opportunity.''
Hudson and Miss Buchheit design most of the programs used in the classes. A typical hour-long class for 31/2- to 5-year-olds includes a spelling and shape review at a large dummy typewriter keyboard, and hands-on experience at the computers typing in LOGO (a simple computer language) commands to ''magically'' produce trucks, circles, rockets, and other objects. The computers have the capacity to produce moving shapes, colors, and prearranged scenarios, if properly programmed.
''Eventually we want them to be able to construct their own universe on the screen - make planets, stars, orbiting moons - by using the things they've learned,'' says Miss Buchheit. ''But before they can do that they need to know their shapes, colors, numbers, and directions. Then they have to know how to make things move in a circle, which means they must use X and Y coordinates. There's a lot of math involved - how far over and up do you want to move the moon or planet, for example. Plus there's a lot of logic - if you make an error, then you have to examine the entire logical sequence of commands to see what you forgot to do. The only thing holding these kids back is their ability to think abstractly, but that grows as we teach them.''
The idle chitchat of adults holds no interest for the computer programmers at the keyboards. Five-year-old Richard Valdez studies an airplane he's created by typing in the word, then glances up at a list of LOGO commands on the wall which correlate colors to numbers. The first number - zero - is the command for clear.
''What would happen if I typed zero?'' he asks.
''I don't know,'' answers Miss Buchheit. ''What do you think would happen?''
Richard ponders a moment. ''Is the glass clear?'' he asks. ''Yes,'' comes the answer.
''Then I think the plane would disappear,'' he concludes. A second later zero is typed in and the plane vanishes.
Richard throws up his hands with glee. ''I knew it would!''