Visual display system having low energy data storage subsystem with date compression capabilities, and method for operating same

A method for operating a data storage subsystem for a visual display device used in computers, the method comprising the following steps:

• storing visual information data in a particular format in a frame buffer for input to a visual display device;
• pre-analyzing the visual information stored in the frame buffer to determine whether the visual information data should be compressed;
• compressing the visual information data in the event that it should be compressed;
• storing the compressed visual information data in a compressed frame buffer for input to the visual display device;
• and
• selectively using the visual information data stored in the frame buffer or the compressed visual information data stored in the compressed frame buffer to repeatedly update the visual display device.

A low energy data storage subsystem for a visual display device used in computers, the data storage subsystem comprising:

• a frame buffer to hold visual information data in a particular format for input to the visual display device;
• a data compressor to compress the visual information data according to a predefined compression/decompression scheme on some occasions, while leaving the visual information data uncompressed other occasions;
• a compressed frame buffer to store the compressed visual information data from the data compressor for use by the visual display device;
• a data decompressor coupled to the compressed frame buffer to decompress the compressed visual information data in real-time according to the predefined compression/decompression scheme as the compressed visual information is being transferred to the visual display device;
• and
• a data input selector to alternatively select for input to a visual display device (1) the uncompressed visual information data from the frame buffer in the event the visual information data is not compressed or (2) the decompressed visual information data from the data decompressor in the event the visual information data is compressed.

A low energy data storage subsystem for a visual display device used in computers;

• the data storage subsystem comprising:
• a frame buffer to hold visual information data in a particular format for input to the visual display device;
• a data compressor to compress the visual information data according to run length encoding (RLE);
• a compressed frame buffer to store the compressed visual information data from the data compressor for use by the visual display device;
• a data decompressor coupled to the compressed frame buffer to decompress the compressed visual information data in real-time according to the RLE encoding as the compressed visual information is being transferred to the visual display device;
• and
• a data input selector to alternatively select for input to a visual display device (1) the uncompressed visual information data from the frame buffer or (2) the decompressed visual information data from the data decompressor.

A visual display system for use in computers, the visual display system comprising:

• a visual display device to depict images in accordance with visual information data that is input thereto;
• a frame buffer to hold the visual information data in a particular format for input to the visual display device;
• a compression analyzer coupled to the frame buffer to determine whether the visual information data held in the frame buffer should be compressed;
• a data compressor, responsive to the compression analyzer, to compress the visual information data according to the predefined compression/decompression scheme in the event that the compression analyzer determines that the visual information data should be compressed;
• a compressed frame buffer to store the compressed visual information data from the data compressor for use by the visual display device;
• a data compressor coupled between the compressed frame buffer and the visual display device to decompress the compressed visual information data in real-time according to the predefined compression/decompression scheme as the compressed visual information is being transferred to the visual display device;
• and
• a data input selector, responsive to the compression analyzer, to alternately input to the visual display device (1) the visual information data from the frame buffer in the event the analyzer determines that the visual information data should not be compressed or (2) the decompressed visual information data from the data decompressor.

A data decompression circuit for decompressing visual information data used in a visual display system for computers, the visual information data comprising a string of characters and being compressed according to run length encoding (RLE) where a repeating character sequence is reduced to a single character plus an associated count of the number of times the character is repeated;

• the data decompression circuit comprising:
• a compressed data buffer to store a byte string of compressed data consisting of characters and counts;
• a character/count indicator buffer to store a bit string of character/count indicators, the character/count indicators being used to identify whether the compressed data held in the compressed data buffer is a character or a count;
• Nd
• an RLE decoding circuit coupled to the compressed data buffer and the character/count indicator buffer, the RLE decoding circuit converting the byte string of compressed data into uncompressed visual information data by repeating a character in the byte string of compressed data according to the count associated with that character, the RLE decoding circuit selectively identifying characters and counts within the compressed data during conversion in accordance with the character/count indicators from the character/count buffer.

A data compression analyzer for evaluating visual information data used in a visual display system for computers to determine whether the visual information data is conductive to compression;

• the visual information data comprising a string of characters held in a frame buffer which, where appropriate, can be compressed according to run length encoding (RLE) where a repeating character sequence is reduced to a single character plus an associated count of the number of times the character is repeated;
• the data compression analyzer comprising:
• a consecutive match counting circuit to count the number of times characters in the visual information data held in the frame buffer are repeated;
• and
• a microprocessor coupled to receive the count from the consecutive match counting circuit, the microprocessor being programmed to initiate RLE compression when the count reaches a selected threshold value.

A data input circuit for a visual display device used in computers, the visual display device depicting images according to visual information data that is input thereto;

• the visual information data comprising a string of characters which can be compressed according to run length encoding (RLE) where a repeating character sequence is reduced to a single character plus an associated count of the number of times the character is repeated;
• the data input circuit comprising:
• a frame buffer to hold the visual information data in a particular format for input to the visual display device;
• a consecutive match counting circuit coupled to the frame buffer to count the number of times characters in the visual information data are repeated, the count being used to determine whether the visual information data should be compressed via RLE;
• a compressed data buffer to store a byte string of compressed data consisting of characters and counts in the event that the visual information data is compressed;
• a character/count indicator buffer to store a string of character/count indicators associated with the compressed data, the character/count indicators being used to identify whether the compressed data held in the compressed data buffer is a character or a count;
• an RLE decoding circuit coupled to the compressed data buffer and the character/count indicator buffer, the RLE decoding circuit converting the byte string of compressed data into compressed visual information data by repeating a character in the byte string of compressed data according to the count associated with that character, the RLE decoding circuit selectively identifying characters and counts within the byte string of compressed data during conversion in accordance with the character/count indicators from the character/count buffer;
• and
• a data input selector coupled to the frame buffer and the RLE decoding circuit to alternately select for input to the visual display device (1) the visual information data from the frame buffer in the event the data has not been compressed or (2) the compressed visual information data from the RLE decoding circuit in the event the data has not been compressed.