【Hitachi】HITAC 201

After the completion of the HITAC 301, Hitachi started working on an affordable compact computer in 1960 that was easy to set up for smaller businesses to do their business accounting on. The result of this development was the HITAC 201.

Hitachi set the HITAC 201’s development targets by getting feedback from its personnel in office managerial departments on the initial specifications. The eventual targets were: (1) develop an inexpensive magnetic tape unit and make it possible to connect around four sortable decks; (2) connect a kana-character line printer; and (3) have a storage capacity of about 4,000 words and an instruction set tailored for business accounting.

The HITAC 201 improved upon the 301’s basic circuitry and achieved a higher mounting density with a different mounting method.

Hitachi added storage capacity to and reduced the cost of the magnetic drum from the HITAC 101’s magnetic drum and increased the belt drive speed to 9,000 RDM. Most magnetic drums at the time were coated and were cooled by drawing in external air, but the 201’s magnetic drum was notable because it used a mechanical mechanism and was completely sealed.

Despite having only just developed its first-ever magnetic tape unit for the KDC-1, Hitachi quickly went about trying to reduce the cost by using small reels (storage capacity of 300,000 digits) and placing four units within one module, with a speed specification of 1,000 digits per second, to share the control circuit.

The HITAC 201 prototype was completed in March 1961. The powerful compact business computer’s entrance made quite a splash in the market.

Specifications of the HITAC 201
Computation method Serial, base10
Fixed-point values
Word length Sign + 11 digits
Instructions 1 1/2 addressing system
37 instructions
Computation speed
 Addition and subtraction
 Multiplication and division
(excluding wait time)
4 ms
30 ms
Storage unit
Average wait time
Magnetic drum
4,000 words
3.3 ms
I/O units Photoelectric paper tape reader
Tape-punch writer
Line printer (120 lines/minute)
Magnetic tape unit

Four decks
0.5 m/s
1,000 digits/s/s
2 digits/mm/mm
300,000 digits/reel

Hitachi HITAC 201 systemHitachi HITAC 201 enclosure