Glossary
107365 Tandem Computers Incorporated Glossary–3
enclosure. A unit composed of one or more labels, such as |THEN| or |DO|, and the
text associated with each label. Enclosures are found only in the TACL built-in
functions #DEF, #IF, #CASE, and #LOOP, which are enclosed in brackets to provide
boundaries for their enclosures. TACL defers execution of text that is associated with
labels until it determines the correct label to use.
Enscribe. A database record management system.
exception. An unusual event that causes TACL to interrupt the normal flow of
invocations and transfer to special code (see exception handler). This unusual event
could be BREAK, a TACL error, or a user-defined exception.
exception handler. A series of TACL statements that perform resource deallocation and
cleanup after an exception.
exclusion mode. The attribute of a lock that determines whether any process except the
lock holder can access the locked data.
expand. A type of invocation (see invoke). To expand a variable, specify the variable
name in brackets; TACL returns the expansion in place of the variable name.
expression. A text, string, or integer constant, a variable, or a value obtained by
combining constants, variables, and other expressions with operators. Expressions are
used as arguments to commands and built-in functions.
extended data segment. One or more consecutive absolute segments that are
dynamically allocated by a process.
extensible data segment. An extended data segment for which swap file extents are not
allocated until needed.
extent. A contiguous area of a disk allocated to the same file.
fault tolerance. The ability of a computer system to continue operating during and after
a fault (the failure of a system component).
file code. An integer value assigned to a file for application-dependent purposes.
file lock. A mechanism that restricts access to a file by all processes except the lock
owner.
file. As used here, a file refers to an organized collection of data stored on a disk. In
general, a file on a Tandem system can be a disk file, a process, or a device.
file name. A unique name for a file. This name is used to open a file and thereby
provides a connection between the opening process and the file. File names consist of
one to eight alphanumeric characters, the first of which must be alphabetic.
file name template. A sequence of characters including the asterisk (*) and question
mark (?) that matches existing file names by expanding each asterisk to zero or more
letters, digits, dollar signs ($), and pound signs (#) and replacing each question mark
with exactly one letter, digit, dollar sign, or pound sign.
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