【NEC】 NEAC-2201

In September 1958, NEC completed their first transistor-based computer, the NEAC-2201. This machine was based on the ETL MARK IV of the Electro Technical Laboratory, and was developed by a team at NEC organized around Hiromu Kaneda and Yoshio Miyagi, and under the guidance of the Electro Technical Laboratory. It was comprised of a computer main unit, a console and input/output devices (a paper tape punch typewriter and a photoelectric tape reader). Germanium alloy high-speed transistors were used as circuit elements, and a magnetic drum was used for the internal memory unit. The system was distinctive in that it was fabricated using only Japanese made components. By using transistors, the system achieved an astonishing level of miniaturization, with a main unit size of only 1.1 meters in width and depth, and 1.6 meters in height. This computer was developed for business use. It employed the decimal system, with 10 decimal digits as 1 word, and addresses were also decimal. A magnetic drum from Hokushin Electric was used for the memory unit. Memory capacity was 1,040 words, with 40 words of that storing the same content 5 times over the circumference, thereby achieving high-speed access with a reduced access time.

This machine was finished in September 1958, and was installed and used in the Electronic Computer Center of the Japan Electronic Industry Development Association (JEIDA). It was displayed at the AUTOMATH Exhibition (an international conference on information processing sponsored by Unesco) held in Paris in June 1959, and provided the world's first public demonstration of a transistor computer. Other countries exhibited transistor computers, but the only one which actually worked was the NEAC-2201. The NEAC-2201 was also more compact and had better performance than the vacuum tube based IBM 650, which was the leading computer model of the time.

NEAC-2201 Specifications
Completion date September 1958
Arithmetic system Decimal, serial, 1-2-4-8 code, fixed point
Arithmetic element Number of transistors: 600
Number of germanium diodes: 7,500
Number of vacuum tubes: 100
Word configuration Word length: Decimal 10 digits
Numeric value length: Fixed point, sign + 9 digits
Command word: Operation part 2 digits + Index register designation part 1 digit + Address 4 digits
Character word: 5 characters
Commands (Instructions) 1•1/2 address system, 63 types
Operation speed Average value including call time
Addition/Subtraction: 5.2ms (1.2ms)
Multiplication: 9.7ms (5.7ms)
Division: 14.1ms (10.1ms)
The value in parentheses is for a high-speed access to the magnetic drum.
Internal memory unit Magnetic drum: 1,000 words (2.5ms)+40 words (0.5ms)
Input/Output unit Photoelectric tape reader
Tape punch typewriter