Glossary
occurrence of a condition that might affect its operation. Event messages are collected centrally and distributed to files, processes, and terminals that are programmed to receive them. They are displayed in text form as operator messages.
execution priority. A numeric-valued attribute of a Compaq process that determines whether the Compaq NonStop Kernel will preempt execution of the process in favor of other processes running in the same CPU. The NonStop Kernel always executes the highest-priority process that is ready to run. In SCF, the execution priority of an FTAM initiator or responder process is determined using the PRIORITY attribute of the PROCESS object.
Expand network. A network of up to 255 Compaq NonStop systems, interconnected using the Expand network operating software. Compaq NonStop systems on an Expand network are referred to as nodes.
extend (write action). To append the data being written to the end of a file.
external process name. See Guardian process name.
FA (flat all data units). An access context for which data is transferred as a sequence of node-descriptor data elements and file-contents data elements. The transfer begins with the node-descriptor data elements, which mark the beginning of data for each node in the structure. This methodology preserves the structural semantics of the file. In Compaq FTAM, the only document type that uses FA is FTAM-2. See access context; contrast with UA.
FADU (file-access data unit). A unit of the file-access structure on which the transfer, delete, extend, replace, and insert actions can be performed. A FADU contains zero or more data units.
FADU-locking functional unit. A functional unit that allows concurrency control locks to be invoked on FADUs.
fault tolerance. The ability of a computer system to continue performing its designated functions when any part of the system fails.
file-access data unit. See FADU.
file-access functional unit. A functional unit that provides for access to an individual FADU in the file-access structure and allows the FADU to be manipulated within the file-access structure.
file-access service class. The service class that allows access to remote files, and includes data manipulation and file management capabilities.
file-attribute group. See attribute group.
file attributes. Information about a file such as file name, storage account, and date and time of (file) creation. File attributes are present from one file access to another, although the actual values of a file attribute may change. See also activity attributes.
file-availability attribute. An attribute that indicates whether a file is available for immediate or deferred access. For example, a file on a nondemountable device might be classified as having immediate availability, whereas a file on a demountable device might be classified as having deferred availability, because a significant delay could be
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