TAL Programmer's Guide

Glossary
Glossary–14 096254 Tandem Computers Incorporated
TNS/R system. Tandem NonStop Series/RISC system. Tandem computers that are
based on RISC technology. TNS/R processors implement the RISC instruction set and
are upwardly compatible with the TNS system-level architecture.
Transaction Application Language. See “TAL.”
type transfer. The conversion of a variable from one data type to another data type.
unblocked global data. Global data you declare before any BLOCK declarations.
Identifiers of such data are accessible to all compilation units in a program.
UNSIGNED. A data type that allocates storage for:
Simple variable bit fields that are 1 to 31 bits wide
Array element bit fields that are 1, 2, 4, or 8 bits wide
unsigned arithmetic operators. The following operators—'+' (unsigned addition) '-',
(unsigned subtraction) '
*
' (unsigned multiplication), '/' (unsigned division), and '\'
(unsigned modulo division).
upper 32K-word area. The upper half of the user data segment. You can use pointers to
allocate this area for your data; however, if you use the CRE, the upper 32K-word area
is not available for your data.
USE statement. A statement that reserves an index register for your use.
user data segment. An automatically allocated segment that provides modifiable,
private storage for the variables of your process.
value parameter. An argument for which a procedure (or subprocedure) passes a value,
rather than the address of the argument, to a called procedure (or subprocedure). The
called procedure or subprocedure can modify the passed value but not the original
argument in the caller’s scope. Contrast with “reference parameter.”
variable. A symbolic representation of an item or a group of items or elements. A
simple variable, array, structure, simple pointer, structure pointer, or equivalenced
variable. A variable can store data that can change during program execution.
VARIABLE procedure. A procedure that you declare using the VARIABLE keyword; a
procedure to which you can add formal parameters but then you must recompile all
its callers; a procedure for which the compiler considers all parameters to be optional,
even if some are required by your code. Contrast with “EXTENSIBLE procedure.”
virtual memory. A range of addresses that processes use to reference physical memory
and disk storage.
volume. A disk drive; a pair of disk drives that forms a mirrored disk.
WHILE statement. A statement that executes a pretest loop during a true condition.
word. A 16-bit storage unit for the INT data type. TAL uses a 16-bit word regardless of
the word size used by the system hardware.
XOR. A bitwise logical operator that performs a bitwise exclusive OR operation.