L. Steven Coles

A graphic monitor program is described. It was developed at Carnegie-Mellon University for the CDC G21 computer, which is a general purpose, batch-processing system with remote entry. The existing G21 system and the graphics hardware are described. The graphic monitor is a resident auxiliary monitor which provides comprehensive managerial capability over the graphical system in response to commands from the human user. It also will respond to commands from a user program through a similar interface, where routine calls take the place of manual actions. Thus the human and program can interact on a symmetrical and equal basis through the medium of the graphic monitor. The choices made in designing the graphic monitor, given the constraints of the existing hardware and computer system, are discussed. The structure of the monitor program and the human and program interfaces are described. There is also a transient swapping version with a small resident part, and provision for swapped used submonitors.