Accelerator Manual Data Alignment Addendum

Accelerator Manual Data Alignment Addendum—524963-001
Glossary-1
Glossary
aligned. In TNS/R native mode, a data item is aligned if its address is a multiple of its size;
for example, a 4-byte data item is aligned if its byte address is a multiple of 4.
misaligned. In TNS mode and accelerated mode, an erroneous address that is odd-byte
aligned; in TNS/R native mode, an inefficient address that is not aligned.
signal. A software interrupt that provides a way of handling certain events, such as
detection of a hardware (or software) fault, a timer expiration, a lack of system
resources, a process sending a signal to itself, or (for OSS processes) a change in the
execution state of another process or another process sending a signal. A signal is an
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 and all OSS processes. (TNS Guardian
processes receive traps instead.) The signal mechanism is much richer for OSS than
for Guardian processes. A SIGILL signal indicates that an instruction could not be
executed because the instruction or its data were invalid. Compare to trap.
TNS/R native mode. The operational environment in which unaccelerated native-compiled
RISC instructions execute.
trap. A software interrupt that provides a way of handling certain events, such as detection
of a hardware (or software) fault, a timer expiration, or a lack of system resources. A
trap is often an indication of a run-time event that requires immediate attention; most
such events preclude continuing the interrupted instruction stream. Traps are
generated for TNS Guardian processes. (TNS/R native Guardian processes and all
OSS processes receive signals instead.) An Instruction Failure trap indicates that an
instruction could not executed because the instruction or its data were invalid.
Compare to signal.