The USAC-3010 and 5010 were ultra-small computers oriented toward the market for office computers, which had still not been established as a concept at the time. These machines were developed by Unoke Electronic Industries (which later became USAC Electronic Industrial, and today is known as PFU) in 1961.
The USAC-5010 was the first computer after the company's founding and ended as a prototype, but the USAC-3010 -- a business machine developed at the same time -- was a general-purpose computer for small and mid-size firms, and it achieved both a compact size and low price (in the 6 to 8 million yen class). Its main features were: (1) a 9-digit decimal word system, (2) 1-1/2 addressing, (3) 40 instructions, (4) 250 kHz dynamic logic circuits, and (5) use of core memory for main memory. The machine employed a system of keeping the sequence counter, index register and buffer register in core memory, and this made it possible to improve programming flexibility and simultaneously achieve a significant reduction of hardware. To distribute weight and make transport easier, the power supply unit of the machine was separate and provided on top of the main unit. The console (provided on the stand to the left of the main unit in the photograph) was used for tasks like main unit operation, and displaying the content of registers during program debugging, but detailed control was done using a keyboard and printer, and this minimized the use of switches and lamps, and thereby reduced costs and simplified the system. Today, the USAC 3010 business machine is preserved at PFU Headquarters.
