Supercomputers are the Lamborghinis of data-processing, capable of tearing through more operations in one second than someone with a hand-held calculator could do in several lifetimes.

The nation that makes the world's fastest computers has a special claim to world leadership in high technology. For years, that nation has been the United States. In a decade or so, it may well be Japan.Two events a week apart show how quickly Japan is moving to surpass the United States in supercomputing:

-Last Monday, Japan's NEC Corp. announced it will come out next year with a family of supercom-puters faster than the machines that will be released about the same time by Cray Research Inc., the Minneapolis-based world leader.

-This Monday, Control Data Corp. said it was folding ETA Systems, the supercomputer operation that lost more than $100 million last year.

Once again, Japanese companies are mounting a single-minded campaign to achieve superiority in a field traditionally dominated by Americans. And once again, their long-term focus is paying off.

"They have a one-track mind. They want to build the best, so they find ways of doing it," said Sidney Fernbach, a consultant and retired director of computer operations at Lawrence Livermore National Laboratory.

Fernbach oversaw supercom-puters at Lawrence Livermore that were used for designing nuclear weapons and experimenting with nuclear fusion. Now he chairs a super-computing committee for the Institute of Electrical and Electronics Engineers.

"I have no optimistic things to say about the U.S. supercomputer industry. I am just horrified," he said in an interview.

Disaster for U.S. supercomputing is not imminent. Cray continues to control about two-thirds of the world market, by one measure. Hundreds of programs have been written to run on Cray machines, and that software will keep customers coming back.

Moreover, Cray's total reliance on supercomputers for a living keeps the company sharply focused on its mission.

"Cray has done a lot of things very, very right," said Michael P. Burwen, president of the Palo Alto Management Group consulting firm.

Otherwise, though, most signs are pointing the wrong way.

-Japan's big three (NEC, Hitachi Ltd. and Fujitsu Ltd.) are vertically integrated, meaning they make everything needed for a supercom-puter from microchips on up. They can tailor chips to their own needs. Cray, in contrast, relies on its competitor Fujitsu for high-speed logic chips.

-Japan makes much faster single processors, forcing Cray and other U.S. companies to compete by lashing together many processors (for Cray, eventually 64).

Making that many work together on a problem is diabolically difficult.

-With the help of Americans, Japanese companies are catching up in their one weak area, software. The Houston Area Research Consortium has become a software bonanza for NEC since the consortium agreed to buy the only Japanese-made super-computer in the United States. The trend is sure to continue as software developers adapt their programs for Japanese machines.

What should be done? The federal government, the world's biggest purchaser of supercomputers, already has a buy-American policy, although procurement rules inhibit potentially fruitful cooperation between buyers and sellers.

The National Science Foundation backs a network of supercomputer centers, but it is aimed more at using the machines than designing better ones.

It is not clear how much good an industry-government research partnership like Japan's 10-year project would do.

Fernbach favors it, while Burwen argues that in Japan, NEC, Hitachi and Fujitsu compete so intensely with each other that they never contributed their best work.

Fernbach favors cultivating new U.S. supercomputer producers by having government agencies in effect promise to buy their first machines.

Besides Cray and ETA, Thinking Machines Corp. of Cambridge, Mass., has sold some supercomputers, and others are expected from Evans & Sutherland Computer Co. and Amdahl Corp. (whose largest shareholder is Fujitsu).

The Japanese most fear International Business Machines Corp., which leads in unit sales of supercomputers if its specially equipped mainframes are counted. IBM is the only company that, like the Japanese, is vertically intgrated from chips on up.

IBM is supporting the start-up Supercomputer Systems Inc., which was founded by former Cray designer Steve Chen. It also is working with Los Alamos National Laboratory to develop a powerful new supercomputer.

Still, Fernbach, for one, is pessimistic. "I think the Japanese are going to steal the whole computer business away from us," he said.