Flash memory directory virtualization
Directory virtualization may be achieved in semiconductor memories, such as flash memories, by providing a system in which files and directories are interchangeable. A directory may be stored at a virtual address which points to various files. From the user perspective, a tree hierarchy may be achieved. From a hardware standpoint, a series of entries in a table may be linked together by various pointers.
1. A method comprising:
storing a file lookup table for a flash memory array in a separate random access memory;
providing an entry in said file lookup table associated with each file or directory in said flash memory array, said flash lookup table storing a shortened file name and a link table index;
providing a dynamic link table in said separate random access memory, said dynamic link table pointed to by said link table index, said dynamic link table pointing to a link list element;
maintaining a link list element in said separate random access memory, said link list element pointing to physical data in said flash memory array;
storing actual files and directories in said flash memory array and storing data, to enable said actual files to be accessed, in said random access memory, each file and directory having an entry in said table;
storing file system data in said random access memory and said flash memory array; and
storing less file system data for each file in said flash memory array than is stored in said random access memory.
2. The method of claim 1 including enabling directories to point to files.
3. The method of claim 1 including populating a file system for the flash memory array using information obtained from a header within said flash memory array.
4. The method of claim 1 including providing the shortened file name in said random access memory which is translatable into a file name for a file stored in said flash memory array.
5. The method of claim 1 including enabling a file to be fragmented into portions, identifying said portions, and providing instance identifiers so that said portions can be accessed from data stored in said random access memory.