Whirlwind

Whirlwind was one of the very first computers; it was enormously influential, for several reasons. It was the first real-time computer, unlike all the other first-generation computers, which were intended only for numerical computation. It was also the first computer with core memory, which was invented for it.

It was built out of vacuum tubes, and used a predecessor to microcode for internal control logic.

Whirlwind was orginally built for use in a flight simulator, but wound up being used to prototype the SAGE air defence system.