International Business Machines Corporation

Charles H Sauer

Todd A Smith

Donavon W Johnson

Grover Herbert Neuman

Larry K Loucks

Amal A Shaheen-Gouda

These master system files define the system characteristics that a user at any node in the system can expect to have. The master system files are mounted remotely from each of the nodes of the system and a local copy of the master system files is kept locally reflecting the current contents of the master system file. If a master system file is not available, the local copy is used in read only mode until the node containing the master is available. In addition, each user has its own file tree organization that dictates the necessary remote mounts of directories to enable a user logged on to any node to have the same view of the system that would be obtained from any other node in the system by that user.

Single system image uniquely defining an environment for each user in a

A distrbuted services program installed on each of a plurality of data processing systems in a network allows the processors to access data files distrbuted across the various nodes of the network. To reduce the network traffic overhead when files at other nodes are accessed, and to preserve the file system semantics, i.e. the file integrity, the accessing of the various files are managed by file synchronization modes. A file is given a first synchronization mode if a file is open at only one node for either read or write access. A file is given a second synchronization mode if a file is opened for read only access at any node. A file is given a third synchronization mode if the file is open for read access in more than one node, and at least one node has the file open for write access. If a file is in either the first or second synchronization mode, the client node, which is the node accessing the file, uses a client cache within its operating system store the file. All read and writes are then sent to this cache. If a file is in the third mode, all read and write requests must go to the server node where the file resides. The node accessing the file does not use the cache in its operating system to access the file data during this third mode.

Growing community of inventors

Austin, TX, United States of America

Charles H Sauer