Every decade has its sought-after professionals: engineers in the '50s, teachers in the '60s and lawyers and MBAs in the '70s. In the '80s, computers have glutted the work place like an army of eager graduates who all saw the same matchbook cover exhorting them to "Go to school! Change your life! Become a computer!" And they have changed our work lives.

Computers are intimidating and hard to get to know, but once they're ensconced in an office with a daily routine and a job to do, they seem like one of the gang.

In the 1970s, Chesapeake & Potomac Telephone bought the first of what is now a fleet of huge computers, so large that at C&P they call them "Queen Marys."

The queens sprawl over three floors of a deliberately nondescript building in suburban Maryland that has backup power supplies in the basement and on the roof. There is a Queen Mary for almost every job imaginable. Some, like CTOCS/COIN, have jobs most phone users couldn't imagine.

CTOCS/COIN stands for Coin Telephone Operations Center Subsystem/Coin- phone Operational and Information Network. It's called CTOCS (pronounced see-tox) to save a couple of hours of conversation every day. CTOCS keeps an unflinching eye on the 100,000 pay telephones in the area. It knows how many people have called on each pay phone in the past. From this, CTOCS figures out how quickly a particular phone's coin box will fill up.

Every day CTOCS lists the coin boxes that need to be emptied--and tells the coin collector the shortest route to get to all those boxes. When the haul of nickels, dimes and quarters comes back at day's end, it tallies the amount for each phone and the total take.

CTOCS remembers, phone by phone, how much money C&P was gypped out of with slugs. It reports this to C&P's fraud control division.

The biggest Queen Mary is RUBIS (Retrieval Update Billing Information System), which keeps track of 4 million customers' bills.

"Before RUBIS we had The Tub. That was any drawer you looked in to find the customer's bill," said Mike Romeres, DMCCSOD--or District Manager, Computer Communications Systems Operations District. With RUBIS, C&P employes at 2,800 terminals can find any bill in seven seconds or less.

Other Queen Marys help telephone repairers fix broken phones. C&P is now considering buying a mammoth computer that will understand Directory Assistance inquiries and answer in a mechanical voice. Bell has already tried out such a system in Arizona. "They wanted to see if people would drop the phone and run if a computer answered," says Romeres, "and they found out that no one seemed to care."

To the 30,000 people who subscribe to The Source, the computer is wine expert, gamesman, anchorman and financial analyst doling out instant advice.

But to the people who run The Source's $25 million computer center in McLean, it's just "The Barnyard"-- nine identical $250,000 Prime computers. Atop each computer sits a stuffed animal so the operators can tell them apart. The Barnyard--Moose (The Founder), Snoopy, Penguin, Unicorn, Miss Piggy, The Troll, Garfield, Elephant and "Poo" Bear--stand at attention facing the glassed-in computer operators' office, where a poster relays a humbling message: "The attention span of a computer is only as long as its electrical cord."

The Source sells information that people can get from libraries, newspapers and textbooks; it exists because of computers like Snoopy and Garfield that can process 1 million instructions per second, and can talk to anybody who has a phone, a home computer and enough money to pay the $20.75 per hour daytime rate ($7.75 an hour after 6 p.m.).

The Barnyard's tricks include 800 different kinds of programs and information, including lessons in Latin, Spanish, French, German and Esperanto. There are programs to compute the thickness of a molecule in angstroms, plot a graph, check the spelling of all words containing ei and ie, and call up the latest news on wire services. You can reserve a plane ticket, a hotel room or a rental car by typing the enthusiastic command LETSGO.

As they juggle queries, the needs of the gang in The Barnyard resemble those of their animal counterparts: a lot of new material has to be fed in and a lot of old material shoveled out.

A typical day starts at 7 a.m. when The Barnyard is fed the commodity prices. All day long, the computers ingest news stories, magazine articles, lists and letters that arrive by tape, telephone and satellite. News items more than a week old and electronic letters more than a month old are dumped. "We think of this as throwing out the old newspapers and putting them in the parakeet's cage," says Bill Reed, operations manager and chief Barnyard anthropomorphizer.

These computers are hardy stock, but about once a week each of them succumbs to a common computer malady: confusion. If a certain bit of information is requested frequently, a computer gets "dogeared" like an often- thumbed page in a book. Moose may have a hard time retrieving the shopworn bit of data. Not used to difficulties, it begins to worry about why it's having problems. Eventually it refuses to take any calls or talk to any of the other computers.

"That's when the Troll steps in, and Moose has what we call an 'out-of-body experience,'" says Reed. Moose's brain and memory are lifted out and replaced with the Troll's.

Mental lapses aside, it's unlikely that the Barnyard will be put out to pasture anytime soon. "They're good at talking to each other and the rest of the world," says Reed.

In 1979 the Nature Conservancy took a chance on a new hire. The kid didn't know anything about the environment or endangered species but seemed like a quick study and a hard worker.

They put him in a room with an air conditioner and told him all about egrets, box turtles and cypress groves and pretty soon he knew more about those things than anyone at the Conservancy.

An idiot savant of sorts, he could rank any species from most populuous to most endangered, and name a suitable habitat for a species in any state--but he couldn't draw even a rough map of the United States.

Soon the new worker could pinpoint the parcel of land that would most efficiently protect the greatest number of species and warn the people at the Conservancy of legal snags they might encounter in trying to acquire the land. But he still couldn't draw a map.

Now that the Conservancy owns the largest private network of land preserves in the United States, the new worker tells them if they are preserving what they set out to preserve.

The worker's heritage-- being a member of the computer genus (Hewlett-Packard species) rather than the human genus--caused some initial problems. Distrustful, the staff would update their laborious manual files before entering new data in the computer. But hard work won allies. Now they go right to the computer with new information. Meanwhile, a line of new converts has formed, waiting to use the computer to solve their printing, accounting and membership problems.

All this is viewed as a mixed blessing. "It made our lives a lot harder than they were before," said Robert Jenkins, vice president for science programs. "Charitably speaking, a computer fills one with aspirations one didn't have before. It's good, but it's also a tar baby."

Meanwhile the HP, with his one-of-a-kind environmental data base, has made the Conservancy a source of information for people who want to know the ecological implications of tampering with a piece of land.

Almost everyone at the Conservancy will now concede that the computer is a member of the team. But he still can't draw a map.

At Boeing Computer Services, the computers do double duty. Twenty-four hours a day they work as time-sharing computers powerful enough to add up all the telephone numbers in the Manhattan phone book in one second. And the heat they produce from their electronic gymnastics warms the other buildings of the company's Vienna, Va., plant.

Time sharing at Boeing means that 1,500 government agencies, companies and now even personal computers worldwide rent computer time by the minute and get the equivalent of 6,000 data processors and $240 million worth of equipment.

This makes the Boeing computers "experts" at everything. They track the number of bears and visitors in the national parks for the National Park Service. They process $100,000 worth of queries a month from the Department of Labor, now that Labor has scrapped its own computer system. The American Psychological Association turns over its statistics problems to the computers; the Department of Transportation uses them to field questions for their Car Recall Hotline; the computers keep a list of every chair and painting in the White House.

Because they bring in enough revenue to put Boeing among the top 10 of the $20 billion-a-year "time sharing" industry, the computers are treated well.

They reside in their own $15 million building. There are sprinklers in the ceilings every few feet in case of fire and the floors are slightly slanted so water will run off in case the sprinklers sprinkle. All other office machinery, especially the printers that produce an invisible paper dust that computers hate, are kept in a separate room. The incoming power is filtered so there are no power surges that might upset the machines, and everything is kept at a constant 68 degrees.

Because they hold government and private industries' most valued secrets close to their chips, the computers are also guarded well. Motion sensors surround the building. Inside, closed-circuit TV cameras take over the guard duty. Passage through any door requires two specially coded cards. Fire and hazard warning lights can pinpoint a potential disaster. Most of these security systems are run by--what else--small computers, supported in turn by around-the-clock human guards.

More than $2 million was spent on 700 batteries, five Cadillac-sized diesel engines and a 20,000-gallon fuel tank to keep the computers running even if the power fails.

Company officials point with pride to their latest water-cooled models. In a world where big is bad and old is 1977, the big IBM 3033, whose debut in 1977 was widely considered a technological breakthrough, is a stepchild. Its unwieldly size is now a joke and visitors are prankishly urged to try to circumnavigate it. Its duties are described in simplistic terms: chewing and spitting out. Everything is relative.