TACL Reference Manual

Glossary
HP NonStop TACL Reference Manual—429513-018
Glossary-3
device subtype.
device subtype. A value that further qualifies a device type. For example, a device type of
4 indicates a magnetic tape drive; if the same device has a device subtype of 2, then
the magnetic tape drive has a 3206 controller.
disk volume. Also called a disk or a volume; a magnetic storage medium. Disk names
consist of a dollar sign ($) followed by one to seven alphanumeric characters (network)
or one to eight alphanumeric characters (local), the first of which must be alphabetic.
EDIT file. . A file in a format defined by the EDIT product.
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.