A Bit-memory Management Unit For Multi-window Displays

There have been various multifunctional workstations developed for office workers and engineers. Most of them can display multi-windows to provide sophisticated user operations. The purpose of this study is to propose a new hardware architecture for the display control unit (DCU) that can provide faster window manipulation. DCUs that are capable of supporting multi-windows have a memory, called a "window buffer,' which keeps a raster image of every window. This paper describes a method to control and manage the window buffer. In this paper, the following methods are proposed: 1) management of each logical screen in the window buffer as an independent two- dimensional address space, 2) bit boundary access to the window buffer and bit block transfer. Construction of the DCU using-these methods is described. It is then clarified by evaluating the performance of the developed DCU that these methods are effective.