Graphical systems - communication : An associative memory approach * by EDGAR

This paper describes the design and preliminary implementation of a graphics system using a large and small computer configuration connected through conventional voice lines. The small computer is driven by both graphical and conventional input/output devices. In this type of system it is extremely important that the communication line carry only messages with high information content, since low speed is one of the major system constraints. Thus, the design of the software system depends heavily on the communication support devices, as well as on the relative power of the computers. Before continuing, it is obviously necessary to define the meaning of some relative terms. Thus . . ' large computer implies, in this article,. anyone of many high-speed, large-memory, timeshared computers, but more 'specifically, an IBM 360/67 working under a general timesharing system developed at the University of Michigan. The graphic system is just another user (i.e., it has no privileged status). The communication link consists of conventional telephone lines using standard tz:ansmission equipment; this means that the transfer rate is in the audible range, which is abysmally slow for intercomputer communication. For those unfamiliar with these transmission rates, a picture of average TV quality would normally require about five to ten