| 摘要 |
<p>An improvement is disclosed to the conventional single node operating system to provide a distributed file management system (DFS) with a plurality of nodes (A,B) and a plurality of files (5). The DFS uses the UNIX operating system tree structure employing inodes (data structure containing administrative information for each file (151,152) to manage the local files and surrogate inodes (s_inode) to manage access to files existing on another node. In addition, the DFS uses a lock table to manage the lock status of files. The method which implements the DFS locking of records and files involves the following steps. If the file is a local file, then the UNIX operating system standard file is used. However, if a remote file is to be locked, the UNIX operating system LOCLF and FCNTL system calls are intercepted and a remote process call (RPC) DFS_LOCK_CONTROL is executed. The server node (A) receives the remote process call and carries out the lock request. The request could entail locking a single record, a set records or the whole file. The server then acknowledges receipt of the RPC by sending a signal while the client surrogate inode is waiting for a reply from the DFS_LOCK_CONTROL RPC. The client confirms the reception of the lock and sends an acknowledgement to the remote server. The server updates the lock table after receiving the ackowledgement, then DFS_LOCK_CONTROL'S acknowledgement, then DFS_LOCK_CONTROL updates the lock table.</p> |
