7 results about "File allocation table" patented technology

A method for managing access to a file for non-volatile memory is implemented by a processing module of a computer system. The non-volatile memory includes multiple clusters. Upon receipt of a read instruction associated with a file, the processing module acquires cluster numbers corresponding to those clusters that store file data of the file from a file allocation table, and searches a file access permissions table to obtain corresponding data access permission codes, thereby determining whether these file data clusters are read access being permitted. If affirmative, the processing module reads the file data into volatile memory, and transmits the file data to an output module.

The invention discloses a damaged target recovery method, a damaged target recovery device, electronic equipment, a nonvolatile storage medium and a computer program product, which are applied to the technical field of storage. And obtaining free file directory entry data and subsequent free file directory entry data from the disk sector data. The method comprises the following steps: analyzing folder information of current file directory entry data and subsequent file directory entry data to obtain initial position information and cluster occupied space values of a plurality of candidate recovery areas, classifying the file directory entry data, and classifying the candidate recovery area containing the most file directory entry data into a cluster occupied space value; and the target recovery area is used for recovering the damaged target. According to the invention, the problem of unsuccessful target recovery in related technologies can be solved, and the damaged target recovery accuracy and recovery efficiency are effectively improved.

The invention relates to a domestic ARM chip-based inertial navigation high-frequency data long-term storage method, which comprises the following steps of: periodically judging a DMA (Direct Memory Access) double-buffer channel data receiving mark in real time in a highest priority data storage task of a system by configuring and transplanting an exFAT (Extensible File Allocation Table) file system and a FreeRTOS (Real-time Operating System); writing the received inertial navigation high-frequency data into a file in the SD card configured to be in an exFAT format, and if the mark is invalid, releasing CPU resources by the storage task to wait for entering next time; meanwhile, redundant operation is provided, the write-in return state of the data file of the SD card is judged in real time, if the write-in is not successful, the write-in operation is repeated for multiple times until the write-in is successful, and the task is quitted, so that the risk of data storage loss is reduced. According to the invention, the 24-hour data volume under the frequency of 1000Hz is greater than 4GB, the continuous storage time is greater than 2000 hours, and all data are completely stored in the SD card, so that the method is suitable for the long-term storage requirement of the inertial navigation field on high-frequency data, and the application and development of the localization technology in high-frequency data processing are promoted.

The present application provides a method and device for establishing a mapping relationship between a backup file and virtual memory, including: triggering a backup memory mapping establishment request for a first backup file block; determining the size of the first backup file block from a backup file allocation table according to a second parameter in the backup memory mapping establishment request; judging whether there is a free virtual memory block in the virtual memory that meets the size of the first backup file block; if not, determining whether there is a reclaimable historical virtual memory block according to the backup file allocation table; judging whether there is a free virtual memory block that meets the size of the first backup file block in the virtual memory after the recovery is completed; using the starting address of the free virtual memory block that meets the size of the first backup file block as the value of the first parameter, storing the first parameter, and establishing a named memory mapping between the first backup file block and the free virtual memory block through the kernel. This solution can realize the expansion of virtual memory.

The invention discloses a quick file expansion method for an exFAT (Extensible File Allocation Table) file system. Relates to the technical field of rapid file expansion, in particular to the technical field of rapid file expansion of an exFAT file system. The problem that the file expansion speed is low is effectively solved, and the compatibility and flexibility of the file expansion method are improved. The method comprises the following steps: S1, confirming whether a file system has enough storage space or not, and marking the file system as a dirty state; s2, traversing the cluster chain table of the to-be-extended file, and finding the last cluster of the to-be-extended file; s3, calculating the number of new clusters required by the to-be-expanded file, and distributing the new clusters; s4, linking the tail cluster of the to-be-allocated file cluster chain table with the head cluster of the new cluster chain table to form a new complete cluster chain table; s5, updating the size of the file to be expanded; s6, setting file attributes, and updating directory entries and inode; and S7, aligning the expanded file. According to the method, the file system does not need to cancel mounting, efficient file expansion can be achieved, and the method is suitable for large-capacity storage equipment with the file size frequently expanded.

The application discloses a kind of disk data management method, recovery method, device, equipment and medium, comprising: when target disk is set to offline state, create bitmap file, when updating operation is performed to target file, determine the disk and storage address where the data block to be updated is stored according to file allocation table, according to the storage address of target data block to be updated, the data state of target data block to be updated in bitmap file is marked as to be updated state.In the online recovery of target disk, determine target data block according to file allocation table, determine data state according to the storage address of target data block, in combination with bitmap file, if it is to be updated state, then update target data block according to target copy, clear the mark of to be updated state of target data block in bitmap file, until all marks are cleared, set target disk to online state.Shorten the time of offline disk online, reduce the IO load of offline disk online.

The present invention discloses a smart password key file storage method based on the SKF standard. The method divides the NORFLASH space into a directory table, a file allocation table, a data area, and a buffer zone, and defines the file system mapping process from the directory table to the file allocation table and then to the data area. For the reading of applications, containers, and files, the file allocation table position is first retrieved from the directory table, and then the file data in the data area is read according to the file allocation table. When writing a file, a linked list structure is adopted, and the current allocation table is sequentially set to record the next allocation table address, and the corresponding directory item is found according to the file name, and the first chain number of the file allocation table is obtained, and data is written to the data address corresponding to the file allocation table address until the writing is completed. The method implements chain file storage management for NORFLASH, implements file storage and access based on the SKF business standard, prevents the generation of fragmented space, and improves query and writing efficiency.