Method and device for reading FAT ( disk files
A disk file and file technology, applied in special data processing applications, instruments, electrical digital data processing, etc., can solve the problems of occupying memory storage space and increasing hardware costs
Active Publication Date: 2012-07-04
北京炬力北方微电子股份有限公司
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Problems solved by technology
According to the FAT specification commonly used in digital products, it takes up to 80 bytes to save the full path name of a file. When the number of files is huge, the full path name of the saved file will occupy a considerable part of the memory storage space. , will lead to an increase in hardware costs
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[0043] In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention will be further elaborated below in conjunction with the accompanying drawings.
[0044] The size of a FAT disk file, the creation time, the starting position of the file data, that is, the first cluster number information are all recorded in the file directory entry, and the length of the file directory entry is 32 bytes. To read a FAT disk file, you must first find this directory item, obtain information such as file size, creation time, and the first cluster number of the file, that is, the starting position of the actual data of the file. When the data needs to be read, then according to the first cluster number of the file, Find the cluster chains in the FAT table and read them one by one. The files mentioned below are all FAT disk files unless otherwise specified.
[0045] According to the FAT specification, the directory entry location informat...
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The invention discloses a method for reading FAT ( disk files, which comprises the steps of: carrying out full section search on specific type files in disk partitions in FAT formats in advance, allocating the sole index number for each searched file; storing sequences of directory entry locating information of N files with N continuous index numbers in a memory, wherein N is a natural number; judging whether the read file index number i is in the sequences or not, if so, directly obtaining the directory entry locating information of the file corresponding to the index number i from the sequences; otherwise, determining a searching direction, storing the index number i and the directory entry locating information of N files adjacent to the index number i in the sequences, and obtaining the directory entry locating information from the sequences; and reading files according to the directory entry locating information. The invention also discloses a device for reading FAT disk files. Inthe scheme of the invention, FAT disk files are quickly read in the condition of occupying little memory space.
Description
technical field [0001] The invention relates to the technical field of computer storage, in particular to an indexing method and device for reading file allocation table (File Allocation Table, FAT) disk files. Background technique [0002] Portable digital products often adopt an embedded system architecture, which includes an embedded storage module on the main circuit board. The storage module usually includes one or more disk partitions. The disk partitions are used to store pictures, video or audio files; It includes a business module, which has a memory, and is used to read files on the storage module into the memory and perform corresponding services, such as displaying pictures or playing audio and video files. The memory can be flash memory or non-volatile memory. [0003] In the process of some digital products using embedded systems to read files on the storage module and perform corresponding services, they usually search for all pictures, music or video files u...
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IPC IPC(8): G06F17/30
Inventor 何亚康叶凯
Owner 北京炬力北方微电子股份有限公司