TAL Programmer's Guide

Glossary
Glossary–4 096254 Tandem Computers Incorporated
CPU. Central processing unit. Historically, the main data processing unit of a
computer. A Tandem system has multiple cooperating processors rather than a single
CPU; processors are sometimes called CPUs.
CRE. Common Run-Time Environment. Services that facilitate D-series mixed-
language programs.
CREDECS. A file, provided by the CRE, that contains external declarations for CRELIB
functions whose names begin with CRE_. See also “CRELIB.”
CRELIB. A library file, provided by the CRE, that contains functions for sharing files,
manipulating $RECEIVE, terminating the CRE, and performing standard math
functions and other tasks.
Crossref. A stand-alone product that collects cross-reference information for your
program.
CROSSREF. A compiler directive that collects cross-reference information for your
program.
cross-references. Source-level cross-reference information produced for your program
by the CROSSREF compiler directive or the Crossref stand-alone product.
C-series system. A system that is running a C-series release version of the Guardian 90
operating system.
data declaration. A means by which to allocate storage for a variable and to associate an
identifier with a variable, a DEFINE, or a LITERAL.
data segment. A segment that contains information to be processed by the instructions
in the related code segment. Applications can read and write to data segments. Data
segments contain no executable instructions.
data space. The area of virtual memory that is reserved for user data and system data.
The current data space of your process consists of a user data segment, an automatic
extended data segment if needed, and any user-defined extended data segments.
data stack. The local and sublocal storage areas of the user data segment.
data type. A part of a variable declaration that determines the kind of values the
variable can represent, the operations you can perform on the variable, and the
amount of storage to allocate. TAL data types are STRING, INT, INT(32), UNSIGNED,
FIXED, REAL, and REAL(64).
data type alias. An alternate way to specify INT, REAL, and FIXED(0) data types. The
respective aliases are INT(16), REAL(32), and INT(64).
Debug. A machine-level interactive debugger.
DEFINE command. A TACL command that lets you specify a named set of attributes and
values to pass to a process.
DEFINE. A TAL declaration that associates an identifier with text such as a sequence of
statements.