4th March 1956
Wang sells core memory patent to IBM

An Wang, working at the Harvard Computation Lab, developed a magnetic pulse controlling device, the founding principle for all magnetic core memory. In 1949, Wang submitted a patent which was subsequently awarded in 1955.

In 1956, Wang sold the rights for his core memory patent to IBM for $500,000.

The key problem that Wang solved was how to read magnetically stored information without destroying it. Wang's solution was to realize that destroying the data did not matter if it was rewritten immediately after reading. Wang wrote in his June 29 1948 notebook entry:

"...it is very possible that the information can stay there and be transferred many times before the information [is lost]..."

Wang later expanded on this concept:

"The idea is that by destroying the information - I know it."

Despite Wang's important breakthrough, it is Jay Forrester who is considered the inventor of core memory. Forrester ultimately perfected core memory at MIT, initially using it in the 1951 Whirlwind computer.

Related information:

• Centre for Computing History: Magnetic core memory
• IEEE Computer Society: Computer Pioneers - An Wang
• US Patent 2708722, An Wang, "Pulse transfer controlling device"

Image:

• Front cover of Wang's 1949 core memory patent
  Credit: Public domain.

Related Items in the Collection:

Jay Forrester records idea for core memory

Jay Forrester installs magnetic core memory at MIT

Core memory inventor Jay Forrester is born

Jay Forrester patents magnetic-core memory