4 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 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 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.