In the years during and after World War II, MIT played a prominent role in developing technologies that helped the U.S. military defeat Nazi Germany and imperial Japan, and later in creating systems used to track aircraft during the Cold War. In the process, the Institute created the world’s first real-time digital computer and the first electronic navigation system — a forerunner of today’s GPS.These pioneering developments were among those recognized Wednesday at the Boston-area dedications of three commemorative plaques from the IEEE recognizing the projects as “Milestones” in the field.MIT’s Project Whirlwind computer, developed beginning in 1944 in a building at 211 Massachusetts Ave. in Cambridge, was the first computer ever to use magnetic-core memory — a system that went on to dominate the computer industry for two decades. It was also the first to use a CRT display to show its output, and the first that was fast enough to provide real-time computations, allowing it to be used to control an aircraft simulator for bomber pilots.Jay Forrester, an MIT professor emeritus of management who was in charge of the Whirlwind project, spoke at this week’s IEEE event. Forrester summed up the daunting obstacles to this giant leap forward in computing — which also spurred other new technologies along the way.The project began with the U.S. Navy approaching MIT in search of computer systems for future military applications. “This was at a time when no general-purpose, reliable, high-speed computer had yet functioned,” Forrester recalled. Indeed, it wasn’t clear that the demanding specs the Navy wanted to meet were even possible: In one of the initial meetings over the concept, he said, the MIT researchers met with Navy officials who thought the project might cost $100,000; instead, the project wound up costing many millions.“There was a big communication gap in that meeting,” Forrester said. But after further discussions, MIT got the go-ahead for the project it had envisioned.To make the computer feasible, Forrester — the manager of the entire project — rolled up his sleeves and went to work developing a new type of memory storage based on tiny magnets whose orientation could represent ones or zeros. Unlike other memory systems at the time, the cores kept their data even if the power was turned off; they also worked much faster and more reliably than other systems.Advanced as it was for its day, the Whirlwind computer had less computing power than today’s pocket calculators. Its total core memory (now known as RAM) amounted to 2,024 16-bit words, or 4,048 bytes (4 Kb). The computer’s memory, control systems and input and output devices were arrayed in towering racks that took up most of a 2,500-square-foot building.As the Cold War began, the U.S. Air Force became interested in harnessing this computer’s impressive power to develop a real-time monitoring system for radar (which MIT had helped to develop during World War II) to detect possible bomber attacks. That led to the development of a technology recognized this week by the IEEE as another of its Milestones: SAGE , or Semi-Automatic Ground Environment. This system, for which MIT created its Lincoln Laboratory, was not only the first electronic air-defense system, but also a forerunner of today’s air-traffic-control systems and computer networks.“The original plan was for Lincoln Laboratory to shut down after SAGE was developed,” recalled Eric Evans, currently the director of the Lincoln Lab — which is still very much alive, with a staff of 3,700 and a budget of $950 million. After SAGE was developed, and MITRE Corp. spun off to continue its operation and development, the launch of the Soviet Union’s Sputnik and the resulting push for development of aerospace technology led the lab to grow and thrive, Evans said.A third technology developed by MIT during World War II was also recognized this week as an IEEE Milestone: The first electronic navigation system, called LORAN (for LOng RAnge Navigation). Using precisely calibrated signals from an array of transmitters, it provided the first accurate, visibility-independent navigation for planes and ships, proving crucial in enabling the U.S. air campaign against Japan in the Pacific.Though LORAN was ultimately superseded by satellite-based GPS, it remained widely used in air traffic, shipping and timing applications until its official decommissioning in 2010. Even now, a successor system, called LORAN-e, remains in use.The three Milestones will each be commemorated with plaques to be installed near the locations of the original work. Seven other IEEE Milestones are already in the Boston area, including one for the MIT-developed Apollo guidance computer, as well as others for the first electric fire-alarm system and Alexander Graham Bell’s telephone.Looking back at the rapid development of these technologies under intense pressure, Forrester said, “Some people think of it as just a technical problem.” But it takes more than engineering skill to solve such great challenges, he said: “It takes vision, and courage, to stand up to all kinds of doubt and opposition.”At the IEEE Milestones dedication ceremony, Robert Everett — who started at MIT’s Servomechanisms Laboratory in 1943, worked on the Whirlwind project, headed the SAGE project, and then became president of MITRE Corp. — praised Forrester’s leadership. “I worked for Jay for many years,” he said. “He was responsible for Whirlwind, and therefore for the construction of SAGE, and the creation of Lincoln Lab, and MITRE Corp. If it were not for him, the whole computer industry would be quite different.”