DEC PDP-7/IBM 1800 HIGH SPEED INTERFACE REFERENCE MANUAL

The report describes an interface between an IBM 1800 computer and a DEC PDP-7 computer. It has the following features: (1) it allows the transfer of blocks of data directly from the memory of one computer to the memory of the other, at up to 125,000 words per second, in parallel with program execution; (2) it allows a program running on one machine to interact asynchronously with one running on the other through a system of 'attention interrupts'; (3) it is relatively simple to control, being symmetric to both computers; (4) it compensates automatically, in either of two modes, for the difference in word length between the PDP-7 and the 1800.