NEAC 2204

Ishii Yoshiteru, Saito Masato, Yamada Akihiko, and others started developing the NEAC-2204 in 1960. The first unit was completed and shipped in September 1961.The NEAC-2204 took the online, real-time processing and multi-program processing developed for the NEAC-2202 and added stored-program memory and file and I/O devices. The NEAC-2204 was able to execute seven separate programs simultaneously through CPU time-slicing with its stored-program memory. The developers used a magnetic drum for the main memory, since cost concerns outweighed performance, but they balanced this with the computation speed by using magnetic core buffer memory as cache memory. The NEAC-2204 could control up to seven I/O devices simultaneously thanks to a time-division methodology. Therefore, the computer supported many different I/O devices, including the NEAC-Writer, photoelectric tape readers, high-speed paper-tape punchers, card I/O devices, and high-speed teletypewriters.