Data processing: software development – installation – and managem – Software program development tool – Translation of code
Reexamination Certificate
1998-11-09
2001-12-11
Chaki, Kakali (Department: 2122)
Data processing: software development, installation, and managem
Software program development tool
Translation of code
C717S152000
Reexamination Certificate
active
06330712
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a compressed data patch system for use on a read-only memory device, and more particularly to a compressed data patch system allowing compressed data in the read-only memory device to be modified as if it were re-written.
BACKGROUND OF THE INVENTION
A conventional system for modifying data stored in non-erasable read-only memory devices (such as Read Only Memory, hereafter described as ROM) is disclosed in Japanese Patent Kokai Publication JP-A No. Hei 7-129396 (1995). However, the publication does not describe a technology for patching compressed data that is stored in memory. Therefore, when compressed data stored in ROM must be modified to increase functionality or to correct errors, ROM must be replaced regardless of the amount of correction.
Another conventional system for patching a micro-program or a program, at a low cost, is disclosed in Japanese Patent Kokai Publication JP-A No. Hei 8-44551 (1996). The technology requires two types of data, that is, compressed data that is to be patched and patch data that is used to patch the compressed data, to reside in the same device. Therefore, when the memory device is a non-erasable read only device such as ROM, ROM must be replaced even if only patch data must be replaced
SUMMARY OF THE DISCLOSURE
According to the inventor's investigation toward the present invention the conventional systems have the following drawbacks.
Japanese Patent Kokai Publication JP-A No. Hei 7-129396 does not disclose the above-described conventional patch system for patching compressed data.
A disadvantage of the technology disclosed in Japanese Patent Kokai Publication JP-A No. Hei 8-44551 is that, when a device containing compressed data to be patched and data used to patch the compressed data is read-only, the device must be replaced even if only the patch data must be replaced.
In addition, the technology disclosed in Japanese Patent Kokai Publication JP-A No. Hei 8-44551 compares decompressed read data with patch data on a one-to-one basis and, if their addresses match, sends patch data, in place of decompressed data, to a higher-level unit, meaning that the amount of patch data equals the amount of data of a decompressed read data unit. Therefore, when the amount of one unit of read data is small, the number of read operations increases and the processing speed slows down. Conversely, when the amount of one unit of read data is large, the amount of patch data also becomes large.
Therefore, it is an object of the present invention to provide a novel compressed data patch system allowing compressed data in the read-only memory device to be modified as if it were re-written.
Particularly, it is a concrete object of the present invention to provide a compressed data patch system which stores patch data in an erasable non-volatile memory device to allow compressed data stored in a non-erasable memory device, such as ROM, to be processed as if the compressed data were re-written. This system eliminates the need for replacing the memory device even when only patch data is changed, allowing patch data to be changed repeatedly. In addition, this system, which reduces the amount of data without affecting the speed, requires less resources, costs, and time for patching compressed data.
A compressed data patch system according to a first aspect of the present invention comprises first storing means for storing compressed data, the first storing means being read-only and non-erasable; second storing means for storing patch data to be used for patching the compressed data, the second storing means being erasable and non-volatile; data decompressing means for reading a predetermined amount of the compressed data in response to a request received from an external device, for decompressing the compressed data stored in the first storing means, for storing the decompressed data temporarily, and for sending patched data to the external device; and patching means for patching the data stored temporarily in the data decompressing means using the patch data stored in the second storing means.
A compressed data patch system according to a second aspect of the present invention provides a compressed data patch system as defined by the first aspect wherein the patch data comprises a patch data block module and an index table, the patch data block module comprising at least one patch data block which contains the patch data, size data thereof, and patch start address data. The index table comprises, in order of indexes, one or more indexes each of which contains start address of one or more patch data blocks corresponding to the index which is a high-order word of a physical address of the decompressed data. The plurality of patch data blocks are stored in the patch data block module in order of indexes and, within the same index, in order of patch start physical addresses.
According to a third aspect of the present invention, the compressed data patch system defined by the second aspect has following features: The patch data block further comprises link flag data which is set to a corresponding value if the patch data block is followed by another patch data block within the same index
According to a fourth aspect, the compressed data patch system as defined by the first aspect has following features: The patching means comprises a patch sector address storing means which registers a sector address calculated by dividing a patch start physical address by a predetermined amount of data. The patch start physical address is contained in the patch data, the predetermined amount of data being a unit of data read from an external device, and a patch sector address table into which the sector address is stored.
According to a fifth aspect, the compressed data patch system as defined by the fourth aspect is featured as follows: The patching means further comprises patch sector address checking means which checks if the sector address of the data stored temporarily in the data decompressing means is registered in the patch sector address table and, if the sector address is registered in the table, starts a patching operation.
According to a sixth aspect, the compressed data patch system as defined by the fifth aspect is featured as follows: In response to the patch sector address checking means, the patching means reads from the second storing means at least one patch data block belonging to the sector address whose matching entry is found in the patch sector address table and embeds the at least one patch data block into the decompressed data stored temporarily in the data decompressing means.
According to a seventh aspect, the compressed data patch system as defined by the first aspect is featured as follows: When the patch data on the compressed data is changed, the patch data in the second string means may be re-written.
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patent: 2-162439 (1990-06-01), None
patent: 3-265948 (1991-11-01), None
patent: 6-36549 (1994-02-01), None
patent: 6-250922 (1994-09-01), None
patent: 7-129396 (1995-05-01), None
patent: 8-44551 (1996-02-01), None
Chaki Kakali
NEC Corporation
Young & Thompson
Zhen Wei
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