An article on March 28 incorrectly described the congressional budgetary review of the National Security Agency. The NSA budget is approved by Senate and House committees with responsibility for the agency.

The Washington area's emergence as one of the nation's most important high technology centers is well understood to be a spin-off from the federal government's massive research and development programs.

Not so well known, however, is how the government's most secret agency has spurred the growth of Washington's computer industry and helped build a data-processing climate here second only to the Silicon Valley of California.

The first tantalizing clues--and that is all they are--to the extensive involvement of government intelligence agencies in the computer field can be gleaned from the pages of The Puzzle Palace, the first book every written about the hush-hush National Security Agency.

The sprawling NSA headquarters at Fort George Meade near Baltimore-Washington International Airport is not on any map of the Washington area's high-tech resources, yet it houses what is probably the most sophisticated computer center in the world, suggests author James Bamford.

While the Immigration and Naturalization Service keeps its records on 3-by-5 file cards and the Internal Revenue Service lacks the computer capacity to match up income tax returns with tax-withholding records, NSA is state of the art.

When Cray Research Corp. of Minneapolis produced America's first "super computer"--a machine so powerful it makes a giant IBM 3033 seem like an abacus--NSA was the first customer. The second CRAY-1 manufactured went to NSA's think tank, the Communications Research Division of the Institute for Defense Analysis at Princeton University.

As a clue to the CRAY-1's ability, it can perform 150 million to 200 million calculations per second. Bamford says NSA's computers can store 30 billion words and pluck any one of them from its memory in 80 millionths of a second.

Computers are to NSA's intelligence work what shadowy emigres and turncoat diplomats are to the spymasters created by John LeCarre.

NSA uses its computers for tasks that make finding a needle in a haystack seem like a child's game, which is why Bamford calls the agency "The Puzzle Palace."

Some NSA computers are used to break codes, either by intuitively outsmarting the code-maker or by utilizing what cryptologists call "brute force" to try every possible solution until the right one is found. Other NSA computers are used directly in the agency's primary business--SIGINT, short for "signals intelligence," a euphemism for electronic eavesdroping, wiretapping and bugging.

"Gentlemen don't read each other's mail," Secretary of State Henry Stimson proclaimed in 1929 when he shut down the Black Chamber that had been reading over the shoulder of friend and enemy alike since World War I. Gentlemen no longer have to read each other's mail because NSA's computerized eavesdroping has become America's favorite way to spy.

Massive computer power has long made it possible for NSA to read every international telegram or cable and sort out the messages that are interesting. Applying the same techniques, Bramford says NSA computers can listen to millions of telephone calls with their electronic ears programmed to perk up at the mention of certain words.

Talking computers have been in the toy stores for several years; voice synthesis units are so cheap they can be used to remind motorists to fasten their seat belts. Listening computers are another matter; machines that can hear and respond to a few carefully pronounced words are just now coming onto the market. NSA is widely believed to be on the technological frontier in computer voice recognition. And its computers don't speak just English or Japanese.

Fort Meade also is believed to be the world leader in computerized language translation, with machines capable of scanning a Russian text and almost simultaneously flashing an English translation on the video screen. It may not be coincidental that local firms have recently revealed they are working in the same field.

Though NSA's links to the private sector are a closely guarded secret, the technologies that NSA is most concerned with include several of Washington's high tech specialties--not only computers, but space satellites, telecommunications and electronics.

NSA's technological accomplishments usually are publicized only by accident or international incident--the U-2 crisis, the Pueblo affair, the Liberty incident--but occasionally the veil is lifted. The agency has publicly cautioned private industry about research in such sensitive subjects as cryptology and super computers, when it appeared private scientists were catching up with NSA research.

Like George Smiley's people, NSA employes presumably are not supposed to moonlight. But the private sector undoubtedly lures away some workers who grow restive under the secrecy and discipline of working at Fort Meade, Vint Hill Farm, Friendship Annex, Sugar Grove or one of the other locations whose NSA cover is an open secret.

The 35,000 employes believed to work for NSA--not even Congress gets a budget for the agency--probably constitute the most highly trained work force in the Washington area--computer scientists, programmers, mathematicians, engineers, linguists.

NSA's connections to the private computer companies are through the same revolving door that gives industry executives access to cabinet jobs and lets retired military officers find a second career in defense contracting.

There is no better example of the link between NSA and the computer industry than Admiral Bobby Ray Inman, who at 44 became the youngest director of NSA and later served as deputy director of the CIA, a more visible if not more powerful post.

When Inman left the CIA last year in what was called a policy dispute, he found a job as chief executive of Microelectronics & Computer Technology Corp. Known as MCC, the Washington firm is a research and development consortium created by William C. Norris, chairman of Control Data Corp.

MCC is owned and managed by 10 of the nation's biggest computer and electronics companies and was set up to keep America's computer technology ahead of its Japanese competitors.

Considering Inman's career in intelligence and the crucial role of computer technology in national security, the Japanese may not be all MCC is worried about.