Legend has it that the 1604 designation was chosen by adding CDC's first street address (501 Park Avenue) to Cray's former project, the ERA-UNIVAC 1103.

[4] The first 1604 was delivered to the U.S. Navy Post Graduate School in January 1960[5] for JOVIAL applications supporting major Fleet Operations Control Centers primarily for weather prediction in Hawaii, London, and Norfolk, Virginia.

[6] One of the 1604s was shipped to the Pentagon to DASA (Defense Atomic Support Agency) and used during the Cuban missile crises to predict possible strikes by the Soviet Union against the United States.

[10] The most-significant three bits of the accumulator are converted from digital to analog and connected to a tube audio amplifier contained in the console.

Those familiar with the inner workings of the software could often hear what parts of a task were being performed by the CDC 1604; as a debugging aid, for example, a never-ending repetitive musical phrase indicated the program was stuck in a loop.

Masquerade was a text-mining program that used syntactic structures underlying text data to mask out words and phrases for searching purposes.

The smaller, more elegant, single silo design incorporated two redundant CDC 1604 computer systems, each equipped with dual cabinets containing four 200 bpi magnetic tape drives.

Their BESM-6 computer, which entered production in 1968, was designed to be somewhat software compatible with the CDC 1604,[15] but it ran 10 times faster and had additional registers.