Investigation of computer-to-computer communications systems
Peter T. Kirstein, A R Duncan, H R Gamble, I. H. Gould · ITNOW · 1971
Abstract The PDP-9 at the University of London Institute of Computer Science (ICS), has been developed into a flexible communication machine. It has two synchronous and three asynchronous data adapters. The former can run at any speed up to 50 kbps, dependent only on the timing of the modem attached, and the latter can be adjusted to speeds up to 100 kbps. Most of the work has been at low to medium speeds of 110 to 4800 bps. For various purposes software has been developed for linking the PDP-9 to the IBM 360/75 at the Rutherford Laboratory, the CDC 6600 at the University of London Computer Centre, and the Modular One at ICS. All these links have been at 2400 bps over standard telephone lines. A parallel link to the LUCS ATLAS computer is also in standard operation. Other peripherals have also been connected over the communication channels: these include teletypewriter terminals, a storage tube display, a character printer and a card reader. The computer has a drum backing store, and a comprehensive operating system that allows most of the communication equipment to be used together. The software for the links to the remote computers is in separate overlays, so that message translation and forwarding is possible currently only at that level. Some of the communication facilities implemented are described in the paper.