BOX 4.1 Project Whirlwind and SAGE

Two closely connected computing projects, Whirlwind and SAGE, demonstrate the influence of federal research and development programs during the early days of computing. They not only generated technical knowledge and human resources, but they also forged a unique relationship among government, universities, and industry. The Whirlwind computer was originally intended to be part of a general-purpose flight simulator, but it evolved into the first real-time, general-purpose digital computer. SAGE, an air-defense system designed to protect against enemy bombers, made several important contributions to computing in areas as diverse as computer graphics, time-sharing, digital communications, and ferrite-core memories. Together, these two projects shared a symbiotic relationship that strengthened the early computer industry.

Whirlwind originated in 1944 as part of the Navy's Airplane Stability and Control Analyzer (ASCA) project. At that time, the Navy made extensive use of flight simulators to test new aircraft designs and train pilots; however, each new aircraft design required a separate computer specially created for its particular design. ASCA was intended to negate the need to build individual computers for the flight simulators by serving as a general-purpose simulator that could emulate any design programmed into it. Jay Forrester, the leader of the computer portion of the ASCA project, soon recognized that analog computers (which were typically used on aircraft simulators) would not be fast enough to operate the trainer in real time. Learning of work in electronic digital computing as part of ENIAC at the University of Pennsylvania, Forrester began investigating the potential for real-time digital computers for Whirlwind. By early 1946, Forrester decided to pursue the digital route, expanding the goal of the Whirlwind program from building a generalizable aircraft simulator to designing a real-time, general-purpose digital computer that could serve many functions other than flight simulation.

Pursuing a digital computer required dramatic increases in computing speeds and reliability, both of which hinged on development of improved computer memory—an innovation that was also needed to handle large amounts of data about incoming airplanes. Mercury delay-line memories, which used sonic pulses to record information and were being pursued by several other research centers, were too slow for the machine Forrester envisioned. He decided instead to use electrostatic storage tubes in which bits of information could be stored as an electrical charge and which claimed read-and-write times of a few milliseconds. Such tubes proved to be expensive, limited in storage capacity, and unreliable. Looking for a new memory alternative, Forrester came across a new magnetic ceramic called Deltamax and began working on the first magnetic core memory, a project to which he later assigned a graduate student, Bill Papian.

The expansion of Whirlwind's technical objectives resulted in expanding project budgets that eventually undermined support for the project. Forrester originally planned Whirlwind as a 2-year, $875,000 program, but he increased his cost estimate for the Whirlwind computer itself to $1.9 million in March 1946 and to almost $3 million by 1947 (Campbell-Kelly and Aspray, 1996, pp. 161-163). By 1949, Whirlwind made up nearly 65 percent of the Office of Naval Research (ONR) mathematics research budget and almost 10 percent of ONR's entire contract research



The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement