Method for controlling file request access

摘要

A mirror file number corresponding to a file being requested is transmitted to a host OS. A determination is made as to whether or not caching is performed in the host OS, and reading of the data of the mirror file number is requested to a block device if it is determined that the data of the mirror file number that was transmitted is not cached. The block device acquires the memory address where the corresponding actual contents are stored, corresponding to the sector number, acquires the sequence number corresponding to the contents, changes the acquired sequence number, and reads the data of the acquired memory address. The read data is converted to data with a modified sequence number attached, and the data is provided to the host OS. If it is determined that the data is cached in the host OS, the cached data is provided.

主权项

1. A method of performing a file request access by a user application running on a host operating system (OS) of a programmed computing device, comprising:
receiving at the host OS, from the user application, a sequence number corresponding to the requested file; determining, by the host OS, whether the requested file is a mirror file, the determining including:
identifying a sector number of the requested file;accessing a mirror file entry table (MFET) whose entries list a sector number of each mirror file and an address of the each mirror file;comparing the identified sector number of the requested file with sector numbers listed in the mirror file entry table;upon finding a match between the identified sector number and a sector number listed in the mirror file entry table, determining that the requested file is the mirror file, each mirror file being a different file but accessed via a same physical memory address; andotherwise, determining that the requested file is not the mirror file; determining by the host OS whether or not the data associated with the sequence number that was received is cached in the host OS, the data including the requested file; requesting, by the host OS, to read the data associated with the sequence number to a block device if the host OS determines that the data associated with the sequence number that was received is not cached in the host OS; acquiring, by the block device, a memory address where the data corresponding to a sector number of the sequence number is stored and changing the sequence number; reading, by the block device, the data stored in the acquired memory address; the block device converting the data that was read to data with the changed sequence number attached, and providing the data to the host OS; providing, by the host OS, the data provided from the block device to the user application; and providing, by the host OS, the user application with data for the user application that has been cached in the host OS, if it is determined that the data associated with the sequence number that was received is cached in the host OS.