Debug Manual

Glossary
Debug Manual—421921-003
Glossary-2
code segment
code segment. A segment that contains program instructions to be executed plus related
information. Code segments cannot be altered by an application program; therefore,
they are read from disk but are never written back to disk.
complex instruction-set computing (CISC). A processor architecture based on a large
instruction set, characterized by numerous addressing modes, multicycle machine
instructions, and many special-purpose instructions. Contrast with reduced instruction-
set computing (RISC).
converted process. An executing program that was written to take advantage of at least
one feature of D-series systems. Contrast with unconverted process.
CPU. See central processing unit (CPU).
creation process ID. See process ID.
CRTPID. See process ID.
current selectable data segment. The selectable data segment that is being accessed by
a process. A process specifies the current selectable data segment by calling the
SEGMENT_USE_ or USESEGMENT procedure. Debug can put another segment in
use if a VQ command is issued.
D-series system. A system that is running a D00.00 or later version of the HP NonStop
operating system.
data segment. A type of segment whose logical pages contain information to be processed
by the instructions in the related code segment.
extended data segment. An area of virtual memory used to contain data. An extended data
segment is allocated with contiguous addresses and is treated programmatically as a
single object. The two types of extended data segments are selectable segments and
flat segments. Extended data segments are allocated by the ALLOCATESEGMENT or
SEGMENT_ALLOCATE_ Guardian procedure.
file number. An integer that represents a particular instance of an open of a file. A file
number is returned by an open procedure and is used in all subsequent input-output
procedures to refer to the file. Internally, the file number is an index into the file table.
file system. A set of operating system procedures and data structures that provides for
communication between a process and a file, which can be a disk file, a device other
than a disk, or another process.
flat segment. An extended data segment that has a distinct range of relative addresses
within the environment for the current process. Contrast with selectable segment.
Guardian. An environment available for interactive or programmatic use with the HP
NonStop operating system. Processes that run in the Guardian environment use the
Guardian system procedure calls as their application program interface; interactive