System and methods for optimized screen writing

摘要

System and methods are provided whereby screen write operations, such as common in data processing, are performed at a frequency matched to a user's ability to perceive such information. Specifically, screen writing operations are minimized to only those which are really necessary for perception by the user. In all other instances (i.e., time periods when updating is not needed), image information is written to rapid-access memory. At periodic intervals, the system is interrupted so that a display image (maintained in video memory) is updated from the image stored in the rapid-access memory. A screen device (CRT) coupled to the video memory is updated accordingly (upon the next scan of video memory). By maintaining image data locally, the penalty incurred with frequent, large data transfers to video or display memory is avoided.