What Happened on March 4th

 
An Wang Sells Core Memory Patent to IBM
An Wang sells his patent for magnetic core memory to IBM for $500,000. One of the most important inventions in computer history, core memory was the principal method of random access storage used in digital computers from the mid-1950s until the mid-1970s. The US Patent Office awarded Wang a patent, for what he called a pulse transfer controlling device and which formed part of the solution to using core memory practically, in 1955. It was MIT's Jay Forrester who ultimately perfected core memory, initially used in the 1951 Whirlwind computer.