【NEC】 NEAC-2203

This was developed, based on the NEAC-2201, by a team organized around Hiromu Kaneda and Yoshio Miyagi, with the aim of achieving true business processing. The #1 machine was delivered to the Japan Electronic Industry Development Association in May 1959.

The vacuum tubes used in the NEAC-2201 were replaced by transistors, and floating point was added as an arithmetic method. Magnetic core memory was still expensive, so the memory unit had a 3-level hierarchical organization comprised of magnetic core (240 words), high-speed magnetic drum (2k words, 10,000 rpm) and magnetic drum (10k words, 1,500 rpm, up to 10 drums). Word length was expanded to 12 decimal digits, and the number of instructions and registers were enhanced.

This development was oriented toward EDPS (Electronic Data Processing Systems), and efforts focused on development of peripheral devices and a control system for them. The devices which were developed and connected included a card reader, card puncher, line printer and magnetic tape unit. This computer had an interrupt function, and could run 3 programs via time sharing.

NEAC-2203 Specifications
First Shipment Date May 1959
Arithmetic system Decimal, serial, 1-2-4-8 code
Fixed point, floating point
Arithmetic element
  Transistors Diodes
Main unit :1,338 17,343
Input/Output tape control section :1,241 14,921
Word configuration Decimal 12 digits, Command word: 2 instructions/word
Numeric value word: Fixed point: Sign + 11 digits
Floating point: Sign + characteristic 2 digits + mantissa 9 digits
Character word: 6/word, alphanumeric (including kana)
Commands (Instructions) 88 types, 1 •1/2 address system, 3 index registers
Operation speed
  Fixed point Floating point
Addition/Subtraction :0.24ms 1-3ms
Multiplication :2.5ms 2.8-5.1ms
Division :6.01ms 5.5-7.7ms
Internal memory unit Magnetic drum: 2,000 words (3ms) + 40 words (0.6ms)
Magnetic core: 240 words
External memory unit Magnetic drum: 10k words (20ms)
Other input/output equipment Magnetic tape memory unit - Tape speed: 8,000digits/s
High-speed line printer- Printing speed: 200 lines/min (with 96 char)
Card reader/punch, paper tape reader/punch, interrupt typewriter seat

NEAC-2203NEAC-2203Operation console
Magnetic drum