Jay Forrester filed the first practical computer RAM patent 75 years ago this week — his Magnetic Core Memory patent would be granted five years later

Jay Forrester filed a patent for coincident-current magnetic core memory on May 11, 1951, laying the groundwork for practical computer RAM.

MIT’s Project Whirlwind showed the technology could replace unreliable vacuum-tube memory, and the patent was granted in 1956 as U.S. Patent 2736880.

Magnetic core memory became the dominant computer memory for about two decades and helped power early real-time systems, including SAGE air defense.

The patent later led to disputes with RCA and IBM, eventually ending in a major IBM settlement.