File system and file storage method based on large-capacity optical disc library

A file storage method based on a large-capacity optical disc library, comprising:

• receiving a file access request initiated by an application or a user, wherein the file access request carries a file identifier;
• finding a file directory tree according to the file identifier, and determining that a file corresponding to the file identifier is stored in a temporary storage or an optical disc library;
• if the file corresponding to the file identifier is stored in the temporary storage, opening the corresponding file in the temporary storage according to a virtual address recorded in the file directory tree to complete corresponding access operation;
• if the file corresponding to the file identifier does not exist in the temporary storage but exists in the optical disc library instead, according to a physical address recorded in the file directory tree, reading file content stored in the optical disc library into the temporary storage and completing the corresponding access operation via the temporary storage;
• and
• if the file corresponding to the file identifier is not found in the file directory tree, creating the file corresponding to the file identifier in the temporary storage, and adding the virtual address thereof to the file directory tree.