A confessed computer nut, Mark Goldstein says his desktop model "makes me a lot more productive," allowing him to put together complex studies of energy prices for his boss, Washington lawyer Arnold Berkeley.

And to break the tedium, Goldstein finds more entertaining uses for the machine. "I'm also working on a dance program," he explains. "So far it only does your basic sidestep, but I'm working up to something really interesting."

Some computer specialists say the potential for play has been a factor in the revolution that is only now putting a computer at the manager's fingertips: Executives who bought small personal computers originally as home entertainment devices began taking them to work to handle office chores.

A related impetus has been the drastic reduction in the cost of equipment -- called hardware -- and its growing sophistication, which has increased the capabilities of small computers. Hardware manufacturers say the cost per calculation has dropped by 20 percent each year for the past two decades, and similar reductions are expected soon.

But with the trend has come controversy over whether the small micro- and minicomputers offer advantages to executives that outweigh perceived shortcomings.

The first wave of office automation came in the mid-1970s, when word processing began to replace typewriters at the secretary's desk. Using either minicomputer or microcomputer technology, the word processors were generally limited in their ability to compute. But they gave clerical productivity its biggest boost since the eraser, allowing easy formatting, reproduction and error correction for letters and longer documents.

Small businesses were quick to take advantage of the mini- and microcomputers. Thousands of the small machines have been sold to one-person firms like Jerry Rosen's hardware store in Arlington. "I use it for all my inventory control," Rosen says. "And when I need some figures to help me decide how much of a product to buy, this thing saves me one hell of a lot of money."

But large corporations, which usually have their own main-frame computer and a centralized data-processing operation, have been slow to take advantage of the relatively inexpensive personal computer, which is why some managers have brought their own machines into the office.

Bank of America, for instance, is considering whether to add new functions to its mainframe system or to use personal computers, and the choice isn't clear.

"We really don't feel we have all the information on whether we're making management more productive or less productive," says Lloyd Isaacs, the bank's vice president for international information technologies. "If the manager's cost per hour is at some rate, should he really be the person there typing in or reading out reports?"

Computer experts also argue that microcomputers may introduce inefficiencies if they are not tied into a central data bank. "With a large computer there is a ready means of sharing information," says Harvey L. Poppel, senior vice president at the management consulting firm of Booz, Allen & Hamilton Inc. "If each individual were to maintain autonomy in his selection of personal computers, there would be tremendous duplication of effort." This duplication would be especially wasteful where large amounts of data are needed, or where the same computer program has to be duplicated repeatedly by each microcomputer user.

Still, a Booz, Allen 1979 study of managerial efficiency showed that computer technology, properly employed, could save $100 million annually in managers' time by 1985 and $300 million a year by 1990.

David Liddle, vice president of the office systems business unit of Xerox Corp., says a useful distinction for business in deciding whether to use microcomputers is between "professionals" and "managers." Professionals are "project-oriented," Liddle says. "They are individual contributors, and their job is to manage only their own time and skill." Managers are those responsible for production decisions and those requiring the coordination of other workers' activities.

While Liddle says personal computers may be helpful for professionals, he warns they are not well-suited "for the ongoing project of managing a business," where large amounts of data and complex computations will confound the circuits.

A number of companies seeking to avoid the inefficiency that can accompany decentralization are using a variety of systems that combine the easy access and simple operation of the microcomputer with the processing power and centralized data banks of the main frames.

"For many firms, the microcomputer is super, it's just what they need," says Timothy E. Turnpaugh, vice president and manager of the systems research division of Continental Illinois Bank of Chicago. "For us, we'd need entire freight trains of micros."

The bank's solution is an integrated computer network under which personal terminals -- some of which are almost as portable as a briefcase -- are linked to centralized computers which are in turn linked to each other. Continental Illinois' system is more than three years old and still growing.

"The marginal cost of attaching another user is about the cost of a typewriter --$1,000," says Turnpaugh. Furthermore, the system has a range of special features that no microcomputer -- or traditional main-frame system -- could match. An "electronic mail" system allows some 5,000 users to send messages costing less than 10 cents to virtually anyone in the company.

And while "each of the users feels he can have the system in his hands," Turnpaugh says that what the users get is far more computing power than any microcomputer could offer.

In addition to the risk of inefficiency, the arrival of computers invariably raises the question of how well managers will adapt.

Some say the adjustment need be minimal. "It's not the case that particular managers will be favored over others," says Liddle of Xerox. "It's the manufacturer's job to produce a unit so that computing ability is not important."

"These managers are convinced once they see productivity," says Clarence M. (Buzz) Brooks, a vice president of Digital Equipment Corp., which produces a complete line of office computing equipment. "The software leads them through the system, if it's written well."

But some experts -- especially those who don't work for manufacturers -- warn that some managers may be left behind, not by lack of computing skills but by a refusal to accept the new digital automation.

"It's more a question of personality," says Victor J. Krasen, a consultant with Peat, Marwick, Mitchell & Co. "The changes that occur as a result of computers are much like any other changes in life. Those who resist anything new, or something they don't understand, are going to have difficulties. I've seen turnover in whole departments when they put in a computer."

Ironically, some of the most significant adjustments may have to be made by computer processing personnel, who are riding the new technology wave.

"Their role is changing from that of the operator of a set of machines to that of a senior executive," says Poppel of Booz, Hamilton. "They have to learn how to guide other managers in how they can get the most out of the technology. Those that fight the forces of change will get buried."

However much trouble managers may have, the secretaries have become dependent on computers. "We find that when secretaries change jobs," says Brooks of Digital Equipment, "they really want a job where they can stay near a word processor."

"The system makes this job so much fun," says Mary Jane Forbes, secretary to a DEC vice president who has become expert in the new technology. "You finally have time to think."

Forbes and several other secretaries have only one typewriter left in their common work area. "We share it sort of like we share the Xerox," she says.