Open System Services Programmer's Guide

Glossary
$RECEIVE A special Guardian file through which a process receives and optionally replies to messages
from other processes.
32-bit address
space
The portion of the address space available to users of 32-bit addresses. On TNS/E systems,
32-bit addresses become 64-bit addresses by sign extension. Addresses 0 through 0x7FFFFFFF
designate the first 2 gigabytes (GB) of per-process address space, starting at address 0. Addresses
0x80000000 through 0xFFFFFFFF designate the last 2 GB of global address space, starting at
address 0xFFFFFFFF 80000000.
See also address space.
32-bit addressable In 32-bit address space; accessible via a 32-bit addresss. If something is 32-bit addressable, it
is also 64-bit addressable on a TNS/E system.
32-bit object file An object file resulting from compilation units that specified or defaulted to the ILP32 data model.
64-bit address
space
See address space.
64-bit addressable On TNS/R systems, all memory is 32-bit addressable. On TNS/E systems, all memory is 64-bit
addressable; a subset is 32-bit addressable. Ranges outside that subset are addressable only by
64-bit addresses.
See also 32-bit addressable.
64-bit object file An object file resulting from compilation units that specified the LP64 data model.
absolute pathname A pathname that begins with a slash (/) character and is resolved beginning with the root directory.
Contrast with relative pathname.
accelerated object
code
The MIPS RISC instructions (in the MIPS region) that result from processing a TNS object file with
the Accelerator or the Intel® Itanium® instructions (in the Itanium instruction region) that result
from processing a TNS object file with the Object Code Accelerator (OCA).
accelerated object
file
A TNS object file that, in addition to its TNS instructions, has been augmented with equivalent
but faster sequences of instructions in the language of the target processor. An object can be
accelerated for TNS/R systems using Accel, or for TNS/E systems using OCA, or both.
See also accelerated object code.
Accelerator A program optimization tool that processes a TNS object file and produces an accelerated object
file that also contains equivalent MIPS RISC instructions (called the MIPS region). TNS object code
that is accelerated runs faster on TNS/R processors than TNS object code that is not accelerated.
Contrast with Object Code Accelerator (OCA).
access control list
(ACL)
A structure attached to a software object that defines access permissions for multiple users and
groups. It extends the permissions defined by the file system permission bits by allowing you
specify the access rights of many individuals and groups instead of just one of each.
ACL See access control list (ACL).
address space The addressable memory ranges. Memory addresses are 32 bits wide on TNS/R processors and
64 bits wide on TNS/E processors. The NonStop Kernel supports distinct mappings for each
process, beginning at address 0. On TNS/R processors, this range extends 2 GB. On TNS/E
processors, it extends to 512 GB, but 2 GB beginning at address 0x00000000 80000000 are
reserved (never mapped), to avoid ambiguity with zero-extended 32-bit global addresses. Negative
addresses are global—shared by all processes. On TNS/R processors, global addresses occupy
2 GB. On TNS/E processors, global mappings span the last 512 GB of the address space,
beginning at 0xFFFFFF80 00000000. (Additional global addresses below that range are used
internally by low-level system code.) Memory references can be made to any currently mapped
area of the address space, subject to access permissions.
ANSI The American National Standards Institute.
API See application program interface (API).
application
program interface
(API)
A set of services (such as programming language functions or procedures) that are called by an
application program to communicate with other software components. For example, an application
program in the form of a client might use an API to communicate with a server program.
566 Glossary