CDC 3600

NCAR began operations in 1960 as a National Science Foundation program managed by the non-profit University Corporation for Atmospheric Research. When the Control Data Corporation (CDC) 3600 computer arrived in November 1963, it was installed in a University of Colorado building being constructed at 3215 Marine Street in Boulder, Colo. (Before construction of the Mesa Lab – groundbreaking was in June 1964 and dedication on May 10, 1967 – NCAR was housed primarily on the University of Colorado campus.)

During the summer of 1963, NCAR's Computing Facility (CF) staff – part of the Atmospheric Technology Division at the time – determined that the operating software Control Data was developing would not be ready for the system's installation, and they put together enough of an operating system to be able to use the machine. By early 1964, the CF was able to provide computational services to initial users on the CDC 3600.

The CF became a national computational facility in March 1964, tasked with providing large-scale computing facilities to NCAR and to the national community engaged in atmospheric and related research. By the end of 1964, use of the CDC 3600 had grown from an initial 50 hours per month to more than 300, and the CF had run approximately 19,000 jobs through the system. The CDC 3600 had 32,700 48-bit words of magnetic core memory and supported a FORTRAN compiler.

The CDC 3600 was described as 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.

To make room for some facility modifications and prepare for the arrival of the next system – a CDC 6600 – NCAR moved the CDC 3600 to a building owned by Martin Marietta on Prince Street, where it continued in operation through April 1966.