Rom-Pilot (How do it work? <grin>)
Is this the function of Rom-Pilot?
United States Patent 5,836,013
Greene, et. al. Nov. 10, 1998
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Method and apparatus for compressing system read only memory in a computing system
Abstract
A chipset (platform)-independent method and apparatus for compressing and decompressing a system ROM of a computer (e.g., BIOS, setup program, and one or more option ROMs) are disclosed. The setup program, option ROM, and part of the BIOS are compressed using a lossless compression algorithm. A non-compressible portion of the BIOS includes a decompression algorithm and a shadow RAM block table of chipset-specific registers and bit patterns to write-enable and read-enable shadow RAM (RAM that is mapped to the ROM address space). The compressed data is stored in a compressed data block format with the associated location in memory to decompress the compressed data. Thus, the data can be decompressed anywhere in memory of a target computer. For example, the BIOS is decompressed to shadow RAM and the setup program is decompressed to conventional memory. During the BIOS Power-On Self-Test (POST) process, the compressed system ROM is copied to conventional memory, and the decompression program is executed. The decompression program write-enables shadow RAM (with reference to the the chipset-specific information in the shadow RAM block table), copies the non-compressible BIOS from conventional memory to shadow RAM, and read-enables shadow RAM. The decompression program scans the compressed system ROM for compressed data blocks and decompresses the compressed data therein to the associated locations in memory. If compressed data is located in shadow RAM, shadow RAM is enabled for writing and reading with reference to the chipset-specific information in the shadow RAM block table. If compressed data was decompressed to conventional memory space, this space is cleared before exiting the POST process.
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Inventors: Greene; Todd Michael (Hacienda Heights, CA); Hallin, Jr.; John Edward (Aliso Viego, CA).
Assignee: Phoenix Technologies Ltd. (San Jose, CA).
Appl. No.: 289,104
Filed: Aug. 11, 1994 |
