TOSBAC-3400

This was a computer for scientific/engineering computation which was completed at the end of 1963 based on the KT-Pilot, and announced in the following year. It employed the asynchronous microprogram system whose practicality was confirmed with the KT-Pilot. During the development the project exploited the advantages of the microprogram system -- such as facilitating software development by adjusting the architecture during development. Once completed, however, in order to ensure a good software line-up, it avoided architecture variability like in the KT-Pilot. The asynchronous control and the use of epitaxial transistors for the circuit elements made it possible for the computer to run some tens to hundreds times faster. On the other hand, as a commercial machine, it achieved a lower price by reducing the number of logic elements. It was a word machine of 24 bits/word, and was equipped with 119 instructions and 16 commands for I/O control. The Add and Subtract instructions took 7　microseconds, and memory cycle time was 1 microsecond.

Kyoto Computer Gakuin (Kyoto Computer School) introduced TOSBAC-3400 in 1972, and still preserved the CPU, the magnetic tape drive, the hard disk drive, the paper tape reader, the card reader, the lineprinter, and the X-Y plotter.