Object Code Accelerator Manual

Glossary
Object Code Accelerator Manual—528144-003
Glossary-4
code set
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. that part of virtual memory reserved for user code, user library code, system
code, and system library code. 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.
completion code. A value used to return information about a process to its ancestor
process when the process is deleted. This value is returned in the Process deletion
message, system message -101.
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).
condition code. A status returned in the Environment Register by some file-system
procedure calls to indicate whether the call was successful. A condition-code-greater-
than (CCG) indicates a warning, a condition-code-less-than (CCL) indicates an error,
and a condition-code-equal (=) indicates successful execution.
conversational mode. A mode of communication between a terminal and its I/O process in
which each byte is transferred from the terminal to the processor I/O buffer as it is
typed. Each data-transfer operation finishes when a line-termination character is typed
at the terminal. Contrast with page mode.
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).