Abstract: A data display system in which input-output display devices are connected to a central processor, and users select application programs that are run on the central processor. The control system of the central processor includes a display manager control system and a windowing control mechanism which allows a plurality of tasks to be performed concurrently and the results displayed in areas of a display screen. The windowing control mechanism includes, a task manager control program which runs as an application in the display manager control system and includes means to interact, via the display manager, with the operator to allow applications to be initiated, means to create tasks to control the processing of the application in such a way that the applications can be suspended or resumed according to whether the operator is ready for them, and means to identify to the display manager a coordination controller that the display manager can call to allow the task manager to suspend and resume applications.

Abstract: A digital data display in which each display unit includes a random access, read/write character definition buffer store and a screen buffer. The character definitions and screen buffer for each picture to be displayed are constructed in a remote host central processing unit. In order to minimize the time that a user has a blank screen while new character definition and screen buffer data is sent from the c.p.u. to the display unit, this information is sent in groups relating to rows of character cells on the screen and a coherent picture is displayed growing from the top downwards, giving a roller blind effect. Data relating to the first significant row is sent initially followed by groups of character definitions and screen buffer data, the size of the groups dependent upon the characteristics of the transmission buffer.