NEAC-1101

NEC completed the development of its first digital computer, NEAC-1101, in March, 1958. The hardware utilized parametron devices invented by Goto Eiichi in 1954, and adopted a transformer-coupled system with simplified winding structure, originally invented by NEC. This computer aimed at scientific computation and the first computer in Japan which adopted a floating-point arithmetic unit with seven decimal digits. The arithmetic unit had 3600 parametron devices, 29 instructions. As for its performance, an add/subtract instruction took 3.5ms while a multiply/divide instruction took 8.0ms on the average. The memory unit adopted ferrite core memory with the capacity of 256 words (32 digits per word), with core matrix method using two alternating currents. Input/output units consisted of a tape-reader (600 characters per minute), a tape-punch (600 characters per minute) and a typewriter (400 characters per minute). Following the initial development, the memory capacity was doubled to 512 words, along with other enhancements. The computer had been used in laboratories at NEC for eight years for scientific computation. The outcome of this development greatly contributed to the follow-on parametron-based computers at NEC.