EDUCATORS first became intrigued with the potential of computers as teaching tools back in the 1950s when the technology was first being developed. Recently, however, there has a mad scramble to fill America's classrooms with general purpose microcomputers. The Department of Education estimates that the number of computer terminals in U.S. elementary and secondary schools, which doubled last year, is expected to double again this year. Sales to school systems already make up better than 20 percent of the domestic market in microcomputers, accessories and software.

Those who advocate getting the costly little boxes--which two decades ago would have filled entire rooms--onto every student's desktop claim that computer technology's ability to improve the quality of learning at virtually every level is limitless. Proponents argue that the computer's unique ability to "teach" individuals at their own pace, to tabulate and evaluate performance, and to key in on specific strengths and weaknesses, makes the technology the most powerful teaching tool to come along in decades.

Now, from the heart of Silicon Valley, comes a dissenting voice: computers and schools don't mix.

A. Daniel Peck, an education professor at San Francisco State University, is typical of an increasingly vocal body of skeptics. "We're in a computer religion explosion to the detriment of basic-skills education," Peck says. "We ought to be looking at the extent to which the computer splurge is diluting education; it most certainly is not helping." Peck has organized an ad hoc committee of educators and business people, called the Committee on Basic Skills Education, to combat the march of computers into the schools. A position paper by the group calls for help to "stop the bandwagon" before "the educational system goes overboard on its reliance on microcomputers."

Peck and many others across the land dismiss the clarion call for "computer literacy" in the schools as "a merchandising scam" thrust upon unwitting school boards, teachers and PTAs by overzealous computer salesmen. "Manufacturers are shouting from the rooftops that kids have to be technically literate," says Eric Burtis, a Menlo Park, Calif., electronics firm executive who belongs to Peck's group. "But the gurus of the computer movement in education are in it for selfish reasons."

Meanwhile, others criticize the use of computers in schools on what are almost moral grounds. There are those who believe that "once a computer walks into the classroom, we will lose control over what information flows into the ids of the students," observes Michael Resnik, assistant executive director of the National School Board Association. "They figure we can control the teachers, and we can certainly control what goes into the textbooks, but how can you control a computer once you turn it on?"

Peck's group and others are asking educators to refrain from embracing what may very well be the most important technological development since moveable type.

"When you spit into the wind, you're liable to get a little wet" is the way Peck sees it. That wind is today approaching gale force. The proportion of school districts using instructional computers jumped from 39 percent in the 1981-82 school year to 58 percent by last fall, according to a survey by Connecticut-based Market Data Retrieval. A recent report for the National Science Board on K-12 mathematics curriculum recommends that computers "be introduced into the classroom at the earliest grade practicable." Even the Department of Education has initiated a modest research effort to encourage development of instructional applications for personal computers.

Perhaps the most astonishing thing about the massive investment in computers and "courseware" by school systems--projected to reach $1.5 billion in hardware alone by 1985--is that it comes at a time when many districts are hard pressed to repair leaky roofs and replace faulty boilers. Salaries for math and science teachers, meanwhile, can't be kept competitive enough to prevent instructors from defecting to industry. School administrators are quite simply feeling pressure--from parents, from teachers, and some people feel, from manufacturers.

One thing the Market Data Retrieval survey clearly bears out is that the penetration of computers into schools is uneven. Of the 2,000 largest, richest high schools, 80 percent owned instructional computers as of last spring. But computers were used for educational purposes in only 40 percent of the nation's smaller, poorer schools. That pattern persists at the lower levels as well,

By far the most ambitious proposal to equip American classrooms with minicomputers is one crafted by Apple Computer chairman Steven Jobs under which his company would donate a terminal to every school in the country--all 103,000 of them--in return for a generous tax break from Congress. A modified version passed the House last year and came very close to clearing the Senate, where it has strong support. But even among the ''education technologists," the Apple bill has its critics. "If you think companies are going to donate computers where they don't expect future sales, you're nuts," says a former product manager for a large manufacturer.

The anti-computer activists agree that the new technology will only broaden disparities between wealthy and less privileged students, but they also argue that even in the best school systems, a lot of ground needs to be covered before computer gimmickry can help. They are generally less concerned about computer literacy than functional illiteracy--the 1-in-6 high-school graduates who can't read or write above an eighth-grade level.

"There simply is no way computers are ever going to be able to teach reading, writing and arithmetic," states Burtis. Peck's group labels computer-assisted instruction "the most outlandishly expensive means ever conceived to teach the three Rs." Others, however, maintain that computer competency is on the verge of becoming the fourth R.

Those on both sides of the fence agree there are a number of key issues to be resolved before microcomputers can really make a difference in the classroom. First, teachers need to be educated about the technology; not just how to operate the hardware, but how to integrate the computer into the curriculum. "I'm dubious whether most teachers are sufficiently sophisticated," says Graham Downey, director of the influential Council for Basic Education.

Another critical factor is how computers are applied; as "electronic flashcards" or in interactive learning activities. "The computer is one of many teaching tools," says June Wright of the University of Maryland's Computer Discovery Center. "The whole thing boils down to how are you using it. Are you using it as a gimmick or are you using it to enhance other learning activities in the classroom?"

So far, most of the evidence shows that sophisticated computer technology is often used for fairly primitive learning tasks. A National Education Association teacher- survey conducted last spring, for instance, found that computers are used primarily for mundane drill and practice exercises by 86 percent of the computer-using instructors.

Most educators point to software quality as another major ingredient for the successful application of computers in the classroom. Instructional courseware development has become a burgeoning industry. By almost all accounts, however, most of the software now on the market is mediocre at best. A recent report by Congress' Office of Technology Assessment found that what is sold today is "in general, not very good," and concluded that ''the provision of high quality, reasonably priced educational software is the principal technological challenge."

One group that has zeroed in on the software problem is the Educational Products Information Exchange Institute in New York. The nonprofit institute was founded in the late 1960s to conduct independent evaluations of textbooks. Recently, EPIE graduated into the electronic age, offering analyses of microcomputer hardware, courseware, and even instruction manuals.

"In the past year we've seen enormous developmental changes in the software," says Barbara Garris, who markets EPIE's research results to school districts. Still, she estimates that 80 percent of the courseware being sold is not up to the standards of conventional textbooks. "Even the best that's out now is not all that terrific," agrees Ellen Bialo, who coordinates EPIE's courseware evaluation. "In terms of utilizing the full potential of the computer, it just barely scratches the surface."

Garris, who formerly worked for Commodore Business Systems, suspects that the biggest reason why there are so few companies designing good instructional software is that the payback period is too long. A company can spend thousands of dollars on research and development to design an arcade game (or software for businesses or military applications) and see a return on investment almost immediately, she says, while money spent on educational R&D won't be recaptured for years.

EPIE's mission is to educate educators--whom Garris and Bialo see as unwary consumers of computer products. Only after school administrators and teachers demand better products and develop greater sophistication about how to use them will manufacturers respond with good courseware and hardware, they predict. As a major first step, EPIE recently joined forces with the national Consumers Union to promote its various education projects.

The bottom line in the computers-in-school debate is the need to develop technology that meets the particular needs of the classroom--instead of expecting the educational system to adapt to the technology. To date, most of the instructional software and virtually all of the hardware has been designed to fit the requirements of another user --usually business. The biggest challenge of the 1980s, if the computer "revolution" is going to bear fruit, will be to mold the technology to serve the process of learning, and to breed a new generation of teachers and students who can master that technology.

As one leading educational technology expert recently put it: "The computer is not a magical machine; it's a machine."