A file sharing system, comprising a file access processor and a plurality of application support processors; and the file access processor, in turn, includes a central data access system and a storage system is provided to form directories from data in the database, and to change data in that database. Each support processor includes a local cache to acquire and hold directories formed by the data access system; and for each directory acquired by at least one support processor, the data access system further includes a directory gate and a multitude of directory change blocks holding information describing changes in the database that affect the directory. The directory change blocks established for a given directory are arranged in a first chain anchored to the directory gate established for the directory. For each support processor that has acquired at least one directory, the data access system further includes a directory acquired block for each directory acquired by the support processor. Preferably, the directory acquired blocks established for a given directory are arranged in a second chain also anchored to the directory gate established for the given directory.
In an information processing system including a file shared by computer systems each having a central processing system and a main memory, a method for controlling access to the shared file includes a step of storing blocks read from the file into the main memory when the blocks of the file are updated, and a step of comparing at least a portion of the blocks held in a cache memory with at least a portion of the blocks stored in the main memory. When the comparison of at least the portion of the blocks held in the cache memory with at least the portion of the blocks stored in the main memory indicates mismatching, the block is read from the file into the main memory, and when the comparison indicates matching, the block of the main memory is updated. The data to be updated may be in a resident area, an input/output buffer or a same area.
A system for a distributed computing network for managing instrumentation information from a plurality of network-connected managed entities. One or more instrumentation processes are coupled to each of the network-connected managed entities and configured to gather performance metric values. A first classification process is responsive to information describing a type of input/output operation being performed and is configured to select one or more counters based upon the type of input/output operation being performed. A second classification process is coupled to receive a performance metric value from the one or more instrumentation processes. The second classification process is responsive to a computed logarithm of a measured value of at least one metric to select and increment a particular counter of the one or more counters selected by the first classification process.
A distributed storage system provides a method and apparatus for storing, retrieving, and sharing data items across multiple physical storage devices that may not always be connected with one another. The distributed storage system of the present invention comprises one or more `partitions` on distinct storage devices, with each partition comprising of a group of associated data files. Partitions can be of various types. Journal partitions may be written to by a user and contain the user's updates to shared files. In the preferred embodiment, journal partitions reside on a storage device associated with a client computer in a client-server architecture. Other types of partitions, library and archive partitions, may reside on storage devices associated with a server computer in a client-server architecture. The files on the journal partitions of the various clients may, at various times, be merged into a consolidation file or a file resident within the library partition. If two or more clients attempt to update or alter data related to the same file, the system resolves the conflict between the clients to determine which updates, if any, should be stored in the library partition. The merge operation may occur at various time intervals or be event driven. The archive partition stores files from the library partition.
A data retrieval method and apparatus in a distributed database system. Data is retrieved from a distributed database quickly with a minimum load on each terminal. A contents file is provided in each terminal, and a link file is provided in a center system to coordinate access to the distributed data in each terminal.
A procedure document is maintained by storing procedure records identifying each procedure in the document, step records describing the steps performed in each procedure and substep records for steps broken into substeps. Internal references in one step to another step are delimited so that when the step sequence of a procedure is changed the internal step references can be automatically modified to correspond to the change which is made. In addition, the steps and substeps may contain references to instrument and equipment and setpoints of, e.g., pressure, which are pertinent to the procedure. The procedure records may contain a number of columns indicator which indicates whether the steps and substeps of that procedure will use one column or two columns. Seperate files are maintained to provide cross-referencing for the instruments and equipment as well as the setpoints. A description of the setpoints is maintained in a separate file containing unique setpoint identifiers. Exit conditions in the steps and substeps to another step or substep are also delimited and stored in another file to provide cross-indexing of the exit conditions. Yet another file is maintained with cautions and notes which are desired to appear at particular points in the procedure. Regardless of whether the procedure has one or two columns, the cautions and notes are output using the full two-column width.
