File system for enabling the restoration of a deffective file
First Claim
1. A file management apparatus for a file system, including a data area divided into a plurality of clusters, a file allocation table (FAT) having a plurality of table areas mapped in accordance with said clusters, and a directory having a file attribute area containing at least a file name and a head FAT pointer, comprising:
- a processor; and
a memory having instructions executed by the processor to perform;
during data recording, repetitively writing data in a cluster corresponding to a currently processed FAT and storing a succeeding FAT address in said currently processed FAT to generate a FAT chain; and
restoring a FAT of a destroyed file by generating a FAT map by storing a file number in a map area corresponding to each FAT of said FAT chain for each file, when data recording is not normally terminated, in accordance with the head FAT pointer in said file attribute area of said directory and said FAT chain, and storing an end code in a FAT corresponding to an end of the destroyed file stored in said FAT map in which a file number of the destroyed file is stored, by referring to said generated FAT map.
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Accused Products
Abstract
In the invention it is assumed that in a data recording operation, when the data recording is initiated, the data recording module writes the initial value of the file size in the new file attribute area of the directory, and when the data recording is ended, the data recording module writes the number of clusters as the file size in the new file attribute area. With this assumption, the FAT restoration module examines the file size written in the file attribute area, and distinguishes the first file for which the writing is normally terminated, from the second file for which the writing is not normally terminated. The FAT restoration module tracks the FAT chain of the first file and stores the file number of the first file in the map area corresponding to that FAT. Thereafter, the FAT restoration module tracks the FAT chain of the second file, and stores the file number of the second file in the map area corresponding to that FAT. Therefore, at the least, FATs corresponding to clusters in which data may have been recorded can be designated on the FAT map, and the FAT map can be employed to restore the FAT of the defective file.
47 Citations
22 Claims
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1. A file management apparatus for a file system, including a data area divided into a plurality of clusters, a file allocation table (FAT) having a plurality of table areas mapped in accordance with said clusters, and a directory having a file attribute area containing at least a file name and a head FAT pointer, comprising:
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a processor; and a memory having instructions executed by the processor to perform; during data recording, repetitively writing data in a cluster corresponding to a currently processed FAT and storing a succeeding FAT address in said currently processed FAT to generate a FAT chain; and restoring a FAT of a destroyed file by generating a FAT map by storing a file number in a map area corresponding to each FAT of said FAT chain for each file, when data recording is not normally terminated, in accordance with the head FAT pointer in said file attribute area of said directory and said FAT chain, and storing an end code in a FAT corresponding to an end of the destroyed file stored in said FAT map in which a file number of the destroyed file is stored, by referring to said generated FAT map.
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2. A file management apparatus for a file system, including a data area divided into a plurality of clusters, a file allocation table (FAT) having a plurality of table areas mapped in accordance with said clusters, and a directory having a file attribute area containing at least a file name, a head FAT pointer and a file size of a number of said clusters, comprising:
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a processor; and a memory having instructions executed by the processor to perform; during data recording, setting a head FAT address for said head FAT pointer and an initial value for said file size (cluster number) to generate a new file attribute area in said directory, repetitively writing data in a cluster corresponding to a currently processed FAT while storing a succeeding FAT address in said currently processed FAT to generate a FAT chain, and writing an end code in a last FAT and writing a number of used clusters as said file size in said file attribute area of said directory to finish a recording operation; and restoring a FAT of a destroyed file by searching said file attribute area of said directory to detect a first file having a file size other than said initial value, when data recording is not normally terminated, generating a FAT map by storing a file number of said first file in a map area corresponding to each FAT of the FAT chain of said detected first file, and by additionally storing, in said FAT map, a file number of a second file having a file size of said initial value. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A file system, comprising:
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a file device, including a data area divided into a plurality of clusters, a file allocation table (FAT) having a plurality of table areas mapped in accordance with said clusters, and a directory having a file attribute area containing at the least a file name and a head FAT pointer; and a file management apparatus, comprising; a processor; a memory having instructions executed by the processor to perform; during data recording, repetitively writing data in a cluster corresponding to a currently processed FAT and storing a succeeding FAT address in said currently processed FAT to generate a FAT chain, and restoring said FAT of a destroyed file by generating a FAT map by storing a file number in a map area corresponding to each FAT of said FAT chain for each file, when data recording is not normally terminated, in accordance with the head FAT pointer in said file attribute area of said directory and said FAT chain, and storing an end code in a FAT corresponding to an end of the destroyed file stored in said FAT map in which a file number of the destroyed file is stored, by referring to said generated FAT map. - View Dependent Claims (15, 16)
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17. A file system, comprising:
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a file device, including a data area divided into a plurality of clusters, a file allocation table (FAT) having a plurality of table areas mapped in accordance with said clusters, and a directory having a file attribute area containing at the least a file name, a head FAT pointer and a file size of a number of said clusters; and a file management apparatus, comprising; a processor; and a memory having instructions executed by the processor to perform; during data recording, setting a head FAT address for said head FAT pointer and an initial value for said file size (cluster number) to generate a new file attribute area in said directory, repetitively writing data in a cluster corresponding to a currently processed FAT while storing a succeeding FAT address in said currently processed FAT to generate a FAT chain, and writing an end code in a last FAT and writing a number of used clusters as said file size in said file attribute area of said directory to finish a recording operation, and restoring a FAT of a destroyed file by searching said file attribute area of said directory to detect a first file having a file size other than said initial value, when data recording is not normally terminated, generating a FAT map by storing a file number of said first file in a map area corresponding to each FAT of the FAT chain of said detected first file, and by additionally storing, in said FAT map, a file number of a second file having a file size of said initial value. - View Dependent Claims (18, 19, 20, 21, 22)
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Specification