Computer display apparatus for simultaneous display of data of differing resolution

In a computer system having (i) a digital processor and (ii) a display unit coupled to the digital processor, a method of simultaneously displaying on the display unit screen views of different respective resolutions, each screen view generated from display data output by the digital processor, the method comprising the steps of:

• providing a display controller having (i) a first memory for storing display data corresponding to screen views to be displayed at a first spatial resolution, and (ii) at least a second memory for storing display data corresponding to screen views to be displayed at a second spatial resolution;
• coupling the display controller to the digital processor such that the display controller receives display data from the digital processor, the display data comprising a multiplicity of data pixels, and each screen view comprising a multiplicity of display unit pixels;
• outputting and converting display data in the memories of the display controller in a manner such that for each data pixel of display data from the first memory, the data pixel is repeated to form a respective group of display unit pixels, a respective group of display unit pixels being formed for each data pixel of display data from the first memory;
• coupling a data mixer between the display controller and the display unit;
• in the data mixer receiving display data from the first and second memories;
• and
• in the data mixer, forming output signals by multiplexing the display data received from the first and second memories, the output signals for setting display unit pixels such that the first screen view corresponding to the display data from the first memory is displayed on the displayed unit at the first spatial resolution, and the second screen view corresponding to the display data from the second memory is displayed on the display unit simultaneously with the display of the first screen view and superimposed over the first screen view, but at the second spatial resolution.

Display apparatus for receiving display data for forming screen views of respective different spatial resolutions and for displaying the screen views at respective different resolutions on a display unit, the apparatus comprising:

• a digital processor for transmitting display data comprising a multiplicity of data pixels;
• a display controller corrected to the digital processor, the display controller receiving display data from the digital processor, the display controller having (i) a video random access memory for restoring display data representing graphical elements forming a first screen view to be displayed at a first spatial resolution on a display unit, and (ii) a plurality of dynamic random access memories for storing display data representing image elements forming working screen views to be displayed at a second spatial resolution on the display unit, each screen view comprising a multiplicity of display unit pixels, the display unit having periods of active scan line time in which the display unit scans and updates lines of display unit pixels of a displayed screen view, and the display unit having a time of retrace between each period of active scan line time;
• a buffer connected between the digital processor and the display controller for storing display data transmitted from the digital processor, the buffer storing display data until times of retrace of the display unit, the buffer transferring display data to the display controller during times of retrace of the display unit;
• means for outputting and converting the display data in the memories of the display controller such that each data pixel of display data from the video random access memory is repeated for form a respective group of display unit pixels, a respective group of display unit pixels being formed for each data pixel of display data from the video random access memory;
• and
• a data mixer coupled between the display controller and the display unit, the data mixer receiving display data from the memories of the display controller, the data mixer forming output signals by multiplexing the display data from the video access memory and the display data from one dynamic random access memory, the output signals for setting display unit pixels such that the first screen view corresponding to the display data from the video random access memory is displayed on the display unit at the first spatial resolution and one working screen view corresponding to the display data from one dynamic random access memory is displayed on the display unit simultaneously with the display of the first screen view and superimposed over the first screen view, but at the second spatial resolution.