EPTRACE Manual

Glossary
EPTRACE Manual—528811-002
Glossary-2
code file
code file. See object code file.
code segment. A segment that contains executable instructions of a program or library to
be executed plus related information. Code segments can be executed and also
accessed as read-only data but not written to by an application program. These read-
only and execute-only segments are efficiently shared among simultaneous executions
of that program or library. Therefore, they are read from disk but are never written back
to disk. See also TNS code space.
code set. Codes that map a unique numeric value to each character in a character set,
using a designated number of bits to represent each character. Single-byte code sets
use 7 or 8 bits to represent each character. The ASCII and ISO 646 code sets use 7
bits to represent each character in Roman-based alphabets; these code sets are very
limited and are not appropriate for international use. The single-byte ISO 8859 code
sets use 8 bits to represent each character and can therefore support Roman-based
alphabets and many others including Greek, Arabic, Hebrew, and Turkish. Multibyte
code sets represent characters that require more than one byte, such as East Asian
ideographic characters.
code space. See TNS code space.
compiler extended-data segment. A selectable segment, with ID 1024, created and
selected automatically in many (but not all) TNS processes. Within this segment, the
compiler automatically allocates global and local variables and heaps that would not fit
in the TNS user data segment. A programmer must keep this segment selected
whenever those items might be referenced. Any alternative selections of segments
must be temporary and undone before returning.
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 relative pathname.
CPU. See central processing unit (CPU).
cpu, pin. In the Guardian environment, a number pair that uniquely identifies a process
during the lifetime of the process, consisting of the processor (CPU) number and the
process identification number (PIN).
data segment. A virtual memory segment holding data. Every process begins with its own
data segments for program global variables and runtime stacks (and for some libraries,
instance data). Additional data segments can be dynamically created. See also flat
segment and selectable segment.
DEFINE. An HP Tandem Advanced Command Language (TACL) command you can use to
specify a named set of attributes and values to pass to a process.
distributed system. A system that consists of a group of connected, cooperating
computers.