Jay Forrester installed magnetic core memory at MIT

Jay Forrester installed magnetic core memory at MIT

On 8 August 1953, engineers installed a component that resembled a chain link fence on the Whirlwind computer, a joint project between the Massachusetts Institute of Technology (MIT) and the U.S. Navy. The project, led by MITís Jay W. Forrester and built by engineer William Papian, entailed a real-time interactive simulator and stabilizer analyzer for Navy flight training. The component was the first magnetic-core memory and helped the Whirlwind compute at an impressive speed. This month marks the 50th anniversary of this momentous event, which forever changed computer history.


Forresterís earlier magnetic-core memory benefited RAMACís disk drive. The magnetic-core, a wire mesh of ferrite rings and metal wire, created a location where binary information could be recorded and retrieved magnetically. The ability to pinpoint specific intersections or addresses within the core rings, from which information could be stored and then recalled at random, created an unparalleled innovation in computing. The computerís central processing unit and its memory of stored data, procedures and programs, could now be operated interactively. This interactivity boiled down to one major innovative gain: speed. Random-access memory was born.


Magnetic-core memoryís popularity lasted until integrated circuitry superceded it in the 1970s. But the greatest legacy that Whirlwind, Forrester and magnetic-core memory left lies in the conceptualization of random-access memory and the instantaneous speed of real-time processing. Where would we be today if we could not withdraw money from the ATM, buy gas, or have our checking accounts updated in real time? Or make a hotel or plane reservation? Or sit down with our laptops and work online while our personal computers encompass storage, memory, real time and networking all in one immediately gratifying package? Magnetic-core memory spawned the birth of the random-access era; its anniversary is one worth noting.


The 1953 breakthrough that caused computers to flourish was the magnetic core: a small ferrite doughnut that could be magnetized either clockwise ("zero") or counter-clockwise ("one"). An Wang at Harvard pioneered the use of core, and Jay Forrester at MIT made it practical by inventing a matrix scheme using two wires at right angles to read and write individual cores without having a separate wire for each one.

Magnetic core became the dominant computer memory for 25 years until semiconductor memories were invented. Forrester, who was inducted as a Museum Fellow in 1995, decided shortly after his invention that all the really interesting problems in computer hardware had been solved, and he moved on to other fields where he made equally brilliant and seminal contributions.


One of the first large computers that core memory made possible was a huge system for the military with the combat-speak name of "Semi-Automatic Ground Environment" or SAGE





Jay Forrester installed magnetic core memory at MIT

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