System for file and record locking between nodes in a distributed data processing environment maintaining one copy of each file lock
December 17, 2010. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesMultiprogrammed data processing system with improved interlock control Shared storage for multiple processor systems Double redundant processor Method and means for the sharing of data resources in a multiprocessing, multiprogramming environment Multi-processor system with programmable memory-access priority control Computer system key and lock protection mechanism Method and apparatus for controlling a data access in a data base management system Method and means for the retention of locks across system, subsystem, and communication failures in a multiprocessing, multiprogramming, shared data environment Shared resource locking apparatus Fault tolerant and load sharing processing system InventorsApplicationNo. 629073 filed on 12/17/1990US Classes:707/8, Concurrency (e.g., lock management in shared database)710/200ACCESS LOCKINGExaminersPrimary: Lee, Thomas C.Assistant: Coleman, Eric Attorney, Agent or FirmInternational ClassG06F 012/14AbstractA conventional single node operating system is provided with a distributed file management system (DFS) with a plurality of nodes and a plurality of files. The DFS uses the UNIX operating system tree structure employing inodes (data structure containing administrative information for each file) 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 locking is used. However, if a remote file is to be locked, the UNIX operating system LOCKF and FCNTL system calls are intercepted and an remote process call (RPC) DFS-- LOCK-- CONTROL is executed. The server node receives the remote process call and carries out the lock request. The request could entail locking a single record, a set of 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 acknowledgement from the client surrogate inode. If the server does not confirm the reception of DFS-- LOCK-- CONTROL's acknowledgement, then DFS-- LOCK-- CONTROL updates the lock table.Other References
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