The article discusses the Arma Micro Computer from 1962, which predates common references to the first microcomputer. This 20-pound, transistorized computer was designed for aerospace applications, including navigation and engine control. Despite its advanced features for the time, like a 22-bit serial architecture and a small instruction set with complex operations, it does not meet modern definitions of a microcomputer due to its use of discrete components. The computer used unique storage called transfluxors for non-destructive readouts, contributing to its reliability in aerospace environments.
For more detailed information, you can read the full article at Ken Shirriff’s blog.