Mark Weiser, a computer science professor at the University of Maryland, spends his days fiddling with programs for "supercomputers" on a miniature model he is building in the back of a lab -- an endeavor akin to learning to pilot a jet fighter by practicing on a DC10.

So when the Defense Department last month unveiled plans to build its Supercomputing Research Center in Prince George's County, Weiser became "pretty excited" about the possibility of programming super-sophisticated equipment.

"They will have the very best facilities of this kind in the country," said Weiser, who tinkers with computers all day at the office and manages to get in a few more hours on his home computer after his wife and children are asleep. "I expect I will be hungering to work there."

The Supercomputing Research Center -- where a team of 100 scientists will work to design a computer that is 10,000 times faster than those currently considered "super" -- has set off a flurry of excitement in the county.

As computer scientists dream of getting their hands on the equipment, county officials and developers, with visions of Silicon Valley dancing in their heads, see the center as their chance -- at last -- to compete on an equal footing with Fairfax and Montgomery counties for high-profile, high-revenue, high-technology business.

"There really was a barrier that was broken" when Prince George's landed the center, said County Executive Parris Glendening, noting that a few weeks earlier the county had come agonizingly close to winning a $109 million Defense Department contract for a software research institute.

"Prince George's County clearly has not been perceived as the center of high-technology development," said Glendening, who has led the crusade to draw such firms to the county. "People's perception has been that most of this action has been in Fairfax and Montgomery." But, he added, "I suspect from here on out when people are talking about it they will be saying this activity is going on in Fairfax, Montogmery, and Prince George's."

Frank Gaegler, a local lawyer who is building the 107-acre Renaissance Center office and commercial complex across the street from the supercomputing center site, said the center offered him the key to luring tenants there.

"People that were lukewarm before the Defense Department announcement about locating in that area are now calling and asking, 'When will we start?' " said Gaegler, who plans to break ground for the development within a few weeks.

Three days after the supercomputer project was announced, he said, a Baltimore engineering firm called to express interest in 125,000 square feet of office space at the Renaissance Center.

"It's a glamorous item, no question," Gaegler said of the supercomputing center.

"Our address in a couple of years will be as good as any in Montomgery County," said Bowie Mayor Richard Logue. "I can guarantee that."

Despite the glowing official projections, some observers note that the county still is facing heavy competition -- both locally and nationally -- in its bid to attract high-technology firms.

Gail Garfield Schwartz, an economic development analyst who wrote a report on the area's high-technology firms that was released by the Greater Washington Research Center the day after the supercomputing center announcement, said the degree to which the project will attract firms to the county is unclear.

Schwartz's report found that Prince George's County lagged far behind Fairfax and Montgomery in high-technology development but that Prince George's had good "growth potential" because of the relatively low price of land and a "nucleus" of high-tech firms and government facilities already there.

The supercomputing center "certainly will enhance the county's image as a high-tech place," Schwartz said. But, she cautioned, "In terms of being a magnet for the location of more commercial firms, that's a lot iffier."

Because it is unlikely that private companies will be able to share time on the supercomputers at the center, and because computer companies can easily communicate and share information with one another over long distances, she said, "I can't see any compelling reason why they would locate nearby."

The center is to be built by the Institute for Defense Analysis, a nonprofit organization that conducts research on national security issues for the Defense Department. The IDA will be doing the work for the National Security Agency, a defense intelligence agency that uses computer technology to intercept electronic communications and crack codes.

"We have to stay not just one step ahead, we have to stay way ahead in the computer field," said NSA spokesman Mike Levin. "It's of particular importance in connection with our mission that we're able to do things and analyze information with great speed and rapidity in order to support national decision-makers."

The supercomputing center is the first tenant for the Maryland Science and Technology Center, a 466-acre computer research and development park at routes 50 and 301 in Bowie. The Science and Technology Center, owned by the University of Maryland Foundation and the Carley Capital Group, a Washington developer, was also to have been home to the software research institute, which the university lost last month to Carnegie-Mellon University.

Now, "Those [software] people are going to have to come to us," said Hans F. Mayer, deputy secretary of the Maryland Department of Economic and Community Development. "They're talking about software for what exists," he sniffed. "We're the future."

Said Robert G. Smith, the vice president for university relations, "If we'd had [the software institute] and the supercomputer center, we'd have had it all." But even the supercomputing center alone, he said, "starts the ball rolling in the direction we wanted."

Smith said the 100,000-square-foot supercomputing center is expected to spur construction of 4 million to 5 million square feet of office space by the year 2000, creating jobs for up to 12,000 persons. Those new jobs, he said, "might actually result in 25,000 jobs in peripheral ways in the region" as companies locating in the science center develop the need for lawyers, accountants, insurance agents, printers and other support persons.

In terms of revenue for the state, Mayer said, "Those scientists and engineers don't make $20,000 a year. Assuming an average $7 million-a-year payroll, that is not an insignificant amount of money."

The supercomputing center "will be recognized internationally," he added. "Whenever it is spoken about, it will be 'Maryland.' . . . It will tell the world that we're right up there in terms of a high-technology area," he said.

The development that officials expect the supercomputing center to spur already was expected as the Maryland Science and Technology Center got under way. But, "Until this stage, it had been a paper concept," Glendening said. "Absolutely nothing had happened . . . . This [the supercomputing center] moves it from a concept to a reality."

The University of Maryland's Smith said the simultaneous negotiations on the software institute and the supercomputing center helped keep the latter project secret, as NSA wanted. Whenever word of a big development leaked, Smith said, "Everybody assumed we were talking about the software center. It turned out to be very easy to maintain confidentiality about the supercomputer project."

The Department of Economic and Community Development spent a year wooing the supercomputing center, enticing decision-makers with a $2 million grant and $10 million in industrial revenue bonds to build the center. Gov. Harry Hughes promised $1 million annually for three years to create an Institute of Advanced Computer Studies at the University of Maryland's College Park campus nearby, with 30 new research professors, and he agreed to speed up completion of a new wing for the crowded computer science building.

The city of Bowie helped by promising to extend water and sewer service to the supercomputing center -- a crucial link because sewer service otherwise was expected to be years away -- and by agreeing to let the center's first $1 million in city property taxes go to pay off the cost of the hookup.

And the Carley Capital Group and the University of Maryland Foundation donated 20 acres of land at the park, worth $1.5 million, for the building site -- a tax deductible contribution because the IDA is a nonprofit organization.

A search is under way for a director for the center, and work is expected to begin early next year at temporary quarters in the county. The permanent building is expected to open in 1987.

"It's a real jewel," conceded Franklyn Collins, economic development coordinator for neighboring Howard County, which was angling to attract the supercomputing center.

Although Collins said he might mention the center in promoting the state, he doubted he would try to attract companies to Howard by noting the existence of the supercomputing center nearby