CDC 3600

Control Data Corporation
Clock Speed: 
Dates Used: 
Friday, November 1, 1963 to Friday, April 29, 1966
Microprocessor Peak Teraflops: 
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The Control Data Corporation (CDC) 3600 computer arrived at NCAR in November 1963.

NCAR had begun operations in 1960 as a program of the National Science Foundation and managed by the non-profit University Corporation for Atmospheric Research (UCAR). Prior to the construction (groundbreaking in June 1964) and dedication (May 10, 1967) of the NCAR Mesa Laboratory, NCAR was primarily housed on the University of Colorado (CU) campus in Boulder, CO. NCAR's CDC 3600 was installed in an unfinished University of Colorado building being constructed at 3215 Marine Street in Boulder, CO.

During the summer of 1963, NCAR's Computing Facility (CF) staff, at the time a part of NCAR's Atmospheric Technology Division (ATD), judged that the operating software being developed by Control Data would not ready for the system's installation and themselves put together enough of an operating system to be able to utilize the machine, and by early 1964, the CF was able to provide computational services to initial users on the CDC 3600.

The NCAR CF became a national computational facility in March 1964, with a mission to provide large-scale computing facilities to NCAR and the national community engaging in atmospheric and related research. By the end of 1964, usage of the CDC 3600 had grown from an initial 50 hours per month to over 300 hours per month and the CF had run approximately 19,000 jobs through the system.

The CDC 3600 was a beautiful computer with smoked glass panels and a "solid and stunning" look. Seymour Cray had done much of the basic architecture design work on the CDC 3000 series systems.

NCAR's CDC 3600 had 32,700 48-bit words of magnetic core memory and supported a FORTRAN compiler.

In anticipation of the delivery of, and to make facility modifications to accommodate, its CDC 6600 successor, the CDC 3600 was moved to a building owned by Martin Marietta on Prince Street, where it continued to be operated through April 1966.