When you snap a cassette into your tape recorder, boot up your personal computer or give a talking doll to your child, you are tapping into the technological legacy of the National Security Agency.
Your cassette is a miniature version of the first tape cassettes, monsters with 12-inch reels developed by NSA in the 1960s to provide faster access to eavesdropping tapes.
The microchip that permits your child's doll to "speak" probably contains a mathematical formula written by NSA engineers seeking the perfect electronic model for human speech.
And NSA's millions supported the first steps of the infant U.S. computer industry at a time when it had few commercial customers.
Without NSA, "it probably would have taken 10 or 15 years longer to get where we are" in computing technology, says Stephen T. Walker, a prominent software engineer who spent the first years of his career at the agency. "I think their influence was that profound."
The agency's contracts gave a crucial boost to the computer development at "10 or 12 companies - Control Data, IBM, Cray, GE, RCA, DEC," Mr. Walker says. "They bought the first two or three of everything produced. NSA fostered them to the point that they had a finished product to take to the commercial market."
The story of NSA's influence on American technology has remained largely untold because of the agency's intense secrecy. But the impact has been profound.
The mathematicians, computer scientists and audio experts at Fort Meade have long been high-tech consultants to the entire government. Watergate investigators called on NSA to try to restore the infamous 18-minute gap in the Nixon White House tapes. When Marine Lt. Col. Oliver L. North started his secret network to supply arms to the contras in Nicaragua, he first went to NSA for 15 encryption machines. When the FBI or CIA needs a piece of high-tech gadgetry, the agencies often turn to NSA's workshops for help.
But NSA's biggest contribution to American technology unquestionably was its early computer history. Back in the early 1950s, when useful "computing machines" seem-ed a distant prospect, the code-breakers recognized that even a primitive computer would outstrip humans in the search for subtle patterns in seemingly random numbers and letters of coded messages.
First there was Abner, a homely monster developed by the Army Security Agency and passed down to NSA upon the agency's creation in 1952.
"Abner look-ed like hell," recalls Samuel S. Snyder, 83, a long-retired code-breaker who has written several papers on NSA and the computer. "But it was the most sophisticated computer of its time."
Named for the comics character Li'l Abner ("a big strong guy that didn't know anything"), the code-breakers' first computer had brains built of vacuum tubes and a memory made from a vial of mercury. It was huge - "the size of these two rooms," Mr. Snyder says, gesturing at the living room and dining room of his house in Silver Spring.
"This machine kept going, along with a copy built by engineers, for eight years," Mr. Snyder recalls. "Somehow, we never took a picture of the thing."
By the late 1950s, NSA had installed Bogart and Solo - the first "desk computers," Mr. Snyder says. Not desktop: "It was a desk machine because it could fit inside a desk."
Working with IBM, NSA financed Harvest, a transistorized computer delivered in 1962 that was 100 times faster than anything then on the market. Even as Harvest was under way, NSA created a project called Lightning that poured millions into Sperry Rand, RCA, IBM, Philco and GE, producing seminal research on semiconductors and high-speed circuitry.
"We were always ahead of the country in the number of computers and their power," Mr. Snyder says.
In the mid-1960s, NSA engineers seeking compact, secure communications for the nose cones of nuclear missiles did important, early research on microelectronics.
Later, NSA financed some of the first supercomputers, designed by Seymour Cray, who learned his trade building code-breaking computers in the 1950s. The first Cray supercomputer made its debut in an NSA basement in 1976.
In the last two years, NSA has begun to promote some 40 of its own inventions for commercial adaptation, including devices capable of recognizing faces and fingerprints, and multimedia language-teaching software based on a 30-minute situation comedy. Already, it has licensed a high-speed computing method known as Splash to 11 companies.
Today, an NSA code-breaker on loan to the Johns Hopkins School of Medicine is exploring how the agency's techniques might help crack the ultimate code: DNA, the genetic blueprint of life itself.
The agency is discussing with University of California astron-omers how its radio-spectrum analyzers might scan the universe for extraterrestrial life, according to Dennis J. Sysko, a veteran NSA engineer who heads the new technology transfer )) program.
While most of the agency's technology remains classified, NSA's willingness to share some inventions with the private sector represents a crack in its traditional armor of secrecy.
"The connections are much more obvious now, since every-one's in the information age," Mr. Sysko says.
"After all," he adds, "we've been in the information age for three decades."