The Hunt for Red October (Jack Ryan, #3)

by Tom Clancy

Throughout the oceans of the world, and especially astride the passages that Soviet submarines had to cross to reach the open sea, the United States and other NATO countries had deployed gangs of highly sensitive sonar receptors. The hundreds of SOSUS sensors received and forwarded an unimaginably vast amount of information, and to help the system operators classify and analyze it a whole new family of computers had to be designed, the supercomputers. SOSUS served its purpose admirably well. Very little could cross a barrier without being detected. Even the ultraquiet American and British attack submarines were generally picked up. The sensors, lying on the bottom of the sea, were periodically updated; many now had their own signal processors to presort the data they forwarded, lightening the load on the central computers and enabling more rapid and accurate classification of targets.