Whirlwind: Going Digital

Analog to Digital Timeline: The Critical Years: 1945-1949

Forrester persuaded the Office of Naval Research to fund his real-time, electronic digital offering, saying, “the potential of the digital computer was so great and the benefits derived from its use so immense that the costs involved, no matter how great, were warranted.”

“I do not think anyone else would have developed core storage, had Forrester not done it. The people in other organizations who said they were doing it seemed too dilatory. The history of computer memory would probably have been that of transistor storage followed directly after storage tubes.” —George Valley

“Magnetic core memory was a classic story of luck and pluck: a true epic out of the nineteenth century. The cores developed while I watched, and like a boy reading a Horatio Alger novel, I was inspired.” —George Valley

From Unknowns to Wizards of Air Defense: Whirlwind Morphs to SAGE Computer
Barta Building to Lincoln Laboratory: 1950-1959


Lincoln Laboratory

"The house that Whirlwind built" (1951). Rushed to completion for air defense and the housing of the XD-1 (Whirlwind's IBM-produced clone) in Building F (foreground), Lincoln Laboratory would become MIT's preeminent research facility.

The Cape Cod System

To prove itself a viable air defense computer, Whirlwind and its builders, conducted experimental radar network tests in the air space over New England (Cape Cod System), beginning in 1953. First use of core memory. Whirlwind successfully demonstrated its viability.

XD-1 Arrives

Whirlwind’s IBM-built clone (referred to as Whirlwind II), arrived at Building F as the XD-1 in 1955. The XD-1’s “digital twin”, the XD-2, remained with IBM for co-development coordination.
The XD-1 soon took on its military name: AN/FSQ-7.


Whirlwind descendants, TX-2 and FSQ-32, one with Larry Roberts at the helm, the other with Tom Marill in Santa Monica, recorded the first-ever exchange of digital packets across the continent. Soon there-after, ARPA funded the start of ARPANET.

A selection committee of Forrester, Everett, Norm Taylor, and Bob Wieser picked IBM for the multi-billion dollar project to clone Whirlwind into AN/FSQ-7s for more than 30 Air Force direction centers: The Semi-Automatic Ground Environment (SAGE). Competing companies vying for the contract: Remington Rand, Raytheon, Sylvania, and Bell Labs. 

IBM’s Tom Watson Jr. said it was the most important contract in the company’s history.
It transformed IBM from a maker of tabulating machines to a maker of computers.