Ishii Yoshiteru, Saito Masato, and others were the primary developers of the NEAC-2202, an online, real-time computer intended to mechanize Yamaichi Securities’ processing of buy and sell chits. The first unit was completed and shipped in December 1959. In order to immediately process requests from up to seven terminals, a time-sharing methodology was devised to transfer data between the terminals and the storage unit by stealing CPU cycles. And to reduce the amount of CPU hardware, programs were put on patch boards, each with 50 program steps, and plug-in boards were developed that contained up to 100 constant values, such as tax rates. These innovations meant that the entire CPU was compact enough to fit on a single rack. Because the computer had a small footprint and consumed little power, wiring was easy and no air-conditioning was needed.

Specifications of the NEAC-2202
Completed December 1959
Computation method Control method Fixed-point, serial, base10 Patch board, max. 50 steps
Logic elements transistors 350
diodes 7,000
magnetic cores 360
Word structure 8 digits and 3 decimal places in base10 (negative numbers: 7 digits with a sign)
Instructions 3 1/2 address ing system 11 computation types
Computation speed Addition and subtraction: 1.2 ms Multiplication: 30 ms Division: 40 ms
Internal storage unit (core) 3 words/I/O unit Fixed: 6 words Example: 3 x 7 + 6 = 27 (for seven I/O units)
Constant value memory (mounted by plugs or jacks) 3 digits in base10 x 100 constants
Other I/O units Up to seven tape-punch writers

NEC NEAC-2202 main computer unit (left) and a tape-punch writer (right)Mounting side of a package