The patent document describes a display controller that maintains a primary display image on a computer monitor in compressed subregions or chunks. The controller emulates a conventional frame buffer by making the compressed image appear as if it has a linear address space. Most of the image is compressed, and the remainder is selectively decompressed and cached to satisfy read and write requests. The controller decompresses the display image's constituent subregions and buffers the decompressed data for scanning to the display monitor. The invention provides several advantages, including reduced memory requirements and lower memory bandwidth, while maintaining compatibility with existing operating systems and graphics software. The display controller can be implemented in software or hardware, and it supports various compression techniques, including lossy and lossless forms. The virtual frame buffer control ensures that the display image appears as if it resides in a linear address space, allowing read and write requests to be directed to the appropriate location in the cache. The display controller can handle cache misses by fetching and decompressing the necessary subregion, and it can optimize write operations by allowing writes to the cache without immediately decompressing the corresponding region. The invention is designed to improve the efficiency and compatibility of display architectures in computer systems.The patent document describes a display controller that maintains a primary display image on a computer monitor in compressed subregions or chunks. The controller emulates a conventional frame buffer by making the compressed image appear as if it has a linear address space. Most of the image is compressed, and the remainder is selectively decompressed and cached to satisfy read and write requests. The controller decompresses the display image's constituent subregions and buffers the decompressed data for scanning to the display monitor. The invention provides several advantages, including reduced memory requirements and lower memory bandwidth, while maintaining compatibility with existing operating systems and graphics software. The display controller can be implemented in software or hardware, and it supports various compression techniques, including lossy and lossless forms. The virtual frame buffer control ensures that the display image appears as if it resides in a linear address space, allowing read and write requests to be directed to the appropriate location in the cache. The display controller can handle cache misses by fetching and decompressing the necessary subregion, and it can optimize write operations by allowing writes to the cache without immediately decompressing the corresponding region. The invention is designed to improve the efficiency and compatibility of display architectures in computer systems.