pTAL Reference Manual (H06.08+)

Glossary
HP pTAL Reference Manual—523746-006
Glossary-11
register
register. A facility that stores information about a running process. Registers include the
program register, the instruction register, the local register, the stack register, the
register stack, and the environment register.
relational operator. A signed (<, =, >, <=, >= <>) or unsigned ('<', '=', '>', '<=', '>=', '<>')
operator that performs signed or unsigned comparison, respectively, of two operands
and then returns a true or false state.
release version update (RVU). A collection of compatible revisions of NonStop OS
software products, identified by an RVU ID, and shipped and supported as a unit. An
RVU consists of the object modules, supporting files, and documentation for the
product revisions. An RVU also includes a set of documentation for the overall RVU.
RESIDENT procedure. A procedure you declare using the RESIDENT keyword; a
procedure that remains in main memory for the duration of program execution. The
operating system does not swap pages of RESIDENT code.
RISC. See reduced instruction set computing (RISC).
root operator. The last operator executed on the right side of an assignment statement.
RVU. See release version update (RVU).
scope. The set of levels—global, local, or sublocal—at which you can access each
identifier.
selectable segment. A type of logical segment formerly known as an extended data
segment. The data area for a selectable segment always begins with relative segment
4, and this area can be dynamically switched among several selectable segments by
calls to the Guardian SEGMENT_USE_ procedure. The effect is similar to a rapid
overlaying of one large data area. Compare to flat segment.
shared code. See PIC (position-independent code).
signal. The method by which an environment notifies a process of an event. Signals are
used to notify a process when an error that is not related to input or output has
occurred. A signal is often an indication of a run-time event that requires immediate
attention. Many such events preclude continuing the interrupted instruction stream.
Signals are generated for TNS/R native Guardian processes. (TNS Guardian
processes receive traps instead.) A SIGILL signal indicates that an instruction cannot
be executed because the instruction or its data are invalid. Compare to trap.
simple pointer. A variable that contains the address of a memory location, usually of a
simple variable or an array element, that you can access with this simple pointer.
simple variable. A variable that contains one item of a specified data type.