This was a series of ultra-small computers developed by USAC Electronic Industrial Co., (currently PFU), and marketed by Uchida Yoko. It was the first series in its class in Japan to feature uniform architecture and software throughout the series. The USAC 720 Series was comprised of 5 models and the first model (the USAC 720/10) was completed in September 1971. This series had the following features.
(1) It employed the byte system.
(2) It achieved simultaneous input/output operation and input/output unit standardization by using a true channel mechanism.
(3) An automatic inserter mechanism was standard equipment (font type serial printer).
(4) A macro assembler was provided.
(5) It achieved the functionality of a multi-billing system, which was the forerunner of multi-task systems.
| Model name | USAC 720/10 |
USAC 720/30 |
USAC 720/50 |
USAC 720/70 |
USAC 720/90 |
|
|---|---|---|---|---|---|---|
| Application | Direct Data Processing (DDPS*) | Primarily used for general ledger processing | Multi-billing processing (simultaneously issuing different types of bills) | Primarily online processing for aggregation and distribution of data | Batch processing of high-volume data | |
| Completion date | September 1971 | 1972 | January 1973 | |||
| Main mem- ory unit |
Memory element | Magnetic core | ||||
| Capacity | Max. 8KB | Max. 16KB | ||||
| External memory | Externally mounted drum 131KB | Disk cartridge 278KB | ||||
| Printer | Font type serial printer 15.5char/s (88 fonts), 130digit/line Automatic inserter (standard) |
Same as at left + Line printer (240line/min) | ||||
| Other | Bottom-end machine Model completed first Established DDPS |
Employed magnetic general ledger (single-side 256B) | Connection of a maximum of 3 workstations | Dedicated line connection (1,200bps) | Top-end machine First use of a CRT display |
|
*: "DDPS (Direct Data Processing System" is a system where the generated data is processed by directly inputting it to the system, on the spot, via a keyboard.
