Whirlwind was a large scale, general purpose digital computer begun at the Servomechanisms Laboratory of the Massachusetts Institute of Technology in 1946. It went operational in 1949. The project originated with a contract from the U.S. Navy for MIT to develop an "aircraft stability and control analyzer" (ASCA). MIT took on the ASCA project in 1944, with Jay Forrester as its director.

		In April 1946, it was decided that a digital computer would be required, rather than an analog computer as originally envisioned. The program to build the digital computer, called the Whirlwind, was officially launched. Project Whirlwind was sponsored by the Special Devices Division of the Office of Research and Inventions of the U.S. Navy. The plans called for using the Whirlwind to investigate the problems associated with aircraft stability and control using flight simulation. Jay Forester was the Whirlwind Project director, Robert Everett was associate director. By 1947, Forrester and Robert Everett completed the design of a high-speed stored-program computer for this task. In 1948 construction of the Whirlwind machine started, an effort that employed 175 people including 70 engineers and technicians. Whirlwind took 3 years to build and first demonstrated on April 20, 1951. The project's budget was $1 million a year, and after three years the Navy had already lost interest.
1952 Jay Forrester (far left, standing) and Norman Taylor (far left, pointing) inspect completed circuitry.

Forester and the Whirlwind computer research group soon split away from MIT's Servomechanisms Laboratory and formed the Digital Computer Laboratory. The group became involved with Project Lincoln and became Division VI of the Lincoln Laboratory. Lincoln Labs were formed at MIT in 1951 with F. Wheeler Loomis as director. Division VI of Lincoln Labs also did research on the Whirlwind II (FSQ-7) computer. Jack Gilmore wrote the first assembler program for the Whirlwind in 1951. Up until this point all computers constructed were dedicated to single tasks, run in batch mode. A series of inputs were set up in advance and fed into the computer, which would work out the answers and print them. This was not appropriate for the Whirlwind system, which needed to operate continually on an ever-changing series of inputs. Speed became a major issue, whereas with other systems it simply meant waiting longer for the printout, with Whirlwind it meant seriously limiting the amount of complexity the simulation could include.
		The electrostatic storage tube, like television picture tube, uses a movable electron beam to distribute information over a surface.

The Whirlwind itself took up 3,300 square feet within a two-story building. The drum storage system and data communications interface was located on the ground floor. The CPU, control console and CRT displays were located on the second floor. Power supplies were located in the building's basement and the roof was covered with air conditioning equipment to cool down the system. Power generation was approximately 150 KW. The Whirlwind contained 12,500 tubes, 23,803 crystal rectifiers, 1,800 relays, magnetic drum, magnetic tape. Used for real-time control problems, also general-purpose calculations. The computer was a 16-bit parallel, single-address, binary computer. Instructions and data occupied 16 bit words in memory.

		In the early years of Project Whirlwind, Jay Forrester recognized the limitations of the computer memory systems then available. Electrostatic storage tubes, magnetic drums, tapes, and disks lacked the speed and reliability required for the project. With Forrester's invention of random-access coincident-current core memory, information could be extracted immediately rather than searched for sequentially on tapes or disks. Working with graduate student Bill Papian, Forrester's invention led to an array of ferrite magnetic materials for storing information. In his thesis, entitled "A Coincident-Current Magnetic Memory Unit" (1950), Papian described magnetic core memories, honeycombs of minute magnetic cores strung on wires, through which storage information was read to electronic circuits in the computer. This 1952 invention provided the speed and reliability the project required. Only the arrival of Intel's Solid State technology in 1970 replaced the technology.
The Whirlwind team demonstrated mathematical programs such as simple differential equations.

The first bank of core memory was installed in the Whirlwind on August 8, 1953. Computing speed doubled, and useful operating time increased to more than 90 percent. The same year, Raytheon, Remington Rand, and RCA shifted commercial machine storage emphasis to magnetic core storage, followed a year later by IBM. Although initially unappreciated except by the engineers, scientists, and researchers working on this new technology, its impact on the history of computing would be great. After Whirlwind was completed and running, a design for a larger and faster machine to be called Whirlwind II was begun. But the design soon became too much for MIT's resources. It was decided to shelve the Whirlwind II design without building it and concentrate MIT's resources on programming and applications for the original machine, now called Whirlwind I. When the Air Force decided to construct the SAGE air defense system, IBM, the prime contractor for the AN/FSQ-7 computer based the machine's design more on the stillborn Whirlwind II design than on the original Whirlwind. Thus the AN/FSQ-7 is sometimes incorrectly referred to as "Whirlwind II", even though they were not the same machine or design.
		1951 15 August, Whirlwind mathematical waveform. Oscilloscope display example from the Whirlwind sales booklet.

		Whirlwind I ran in a support role for SAGE until June 30, 1959. Which became the "brain" for the Semi-Automatic Ground Environment air defense system developed by MIT's Lincoln Laboratory in the 1950s. "The SAGE system coordinated the complex system of radar, aircraft, telephone lines, radio links and ships that would detect and identify aircraft when they entered US airspace. This project enabled the American computer industry to learn how to build large, interconnected, real-time data processing systems. Components of the Whirlwind are now located at the Smithsonian Institution in Washington, D.C. and in the Digital Computer Museum in Marlboro, Massachusetts. Jay Forester left Lincoln Labs in 1956 and took a teaching position at MIT. Robert Everett and others eventually left Lincoln Labs in 1959 to form the MITRE Corporation.
1954 Jay Forrester, inventor of magnetic-core memory, holds a 64x64 core memory.