NonStop S-Series Server Description Manual (G06.24+)

Glossary
HP NonStop S-Series Server Description Manual—520331-003
Glossary-23
device
device. A computer peripheral or an object that appears to an application as such. See
also terminal.
dial-out point. A system console from which incident reports are sent to a service provider.
Incident reports are sent only from system consoles defined as the primary and backup
dial-out points (the primary and backup system consoles).
DID. See destination ServerNet ID (DID).
DIMM. See dual inline memory module (DIMM).
direct current (DC). Electric current that flows in only one direction. Contrast with
alternating current (AC).
direct jump area. One of sixteen 256-megabyte portions of the 4-gigabyte virtual address
space. A RISC jump instruction has the ability to jump directly to any location within its
own direct jump area without having to use a far jump table.
directory. A type of Open System Services (OSS) special file that contains directory
entries, which associate names with files. No two directory entries in the same
directory have the same name.
directory entry. In the Open System Services (OSS) file system, an object that associates
a filename with a file. Several directory entries can associate names with the same
file. See also link.
directory loop. In the Open System Services (OSS) file system, an error condition in which
a directory is identified as its own parent directory.
directory special file. See directory.
directory stream. In the Open System Services (OSS) file system, an object with an
opaque data type. A process can sequentially read directory entries from a directory
stream.
directory tree. A hierarchy of directories. In the Open System Services (OSS) environment,
directories are connected to each other in a branching hierarchical fashion such that
only one path exists between any two directories (if no backtracking occurs).
disconnecting means. A device, group of devices, or other means by which the conductors
of a circuit can be disconnected from their source of supply.
discovery. For the OSM and TSM client software, the process of identifying the resources
that exist on an HP NonStop™ S-series server. See also incremental discovery and
initial discovery.
disk bootstrap. A software entity residing on disk that is used to load the HP NonStop™
Kernel operating system image (OSIMAGE) into memory during a system load. A disk
that contains the disk bootstrap is referred to as a bootable disk. The disk bootstrap is