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 large-scale computations for numerical applications. 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.