This was a general-purpose computer from Tokyo Shibaura Electric which was the first commercial computer in Japan to employ providing an ALGOL compiler for practical applications. It was completed in 1960.
Numerical values were expressed in a binary coded decimal format, and floating point calculation was supported. A magnetic drum which did not allow random access was used as the main memory unit, so usedsome design efforts were required, like providing a function for ensuring execution speed by optimizing the arrangement of instruction words by the assembler. Although the TOSBAC-3100 was a general-purpose machine, it was designed particularly for scientific and engineering computation, and was equipped with an ALGOL compiler (WALT) developed with the cooperation of Professors Nakajima and Iwasaki of Waseda University.
On the other hand, the TOSBAC-4200 was developed in 1961 as a dedicated computer for office computation. It used the same circuits as the TOSBAC-3100, magnetic tape for external memory, and magnetic core memory (which had just become practical) as the main memory unit. The development targets included: (1) To enable all the business processing previously performed with PCS (Punch Card Systems), and (2) To enable easy handling of kana characters. The aim was total replacement of the PCSs which were widely used in the business processing field in Japan at that time. One digit (a unit expressing a single character -- numerical, alphabetic or kana) was represented with 8 bits, and thus kana letters could be handled without control codes.