NonStop S-Series Hardware Installation and FastPath Guide (G06.25+)

Glossary
HP NonStop S-Series Hardware Installation and FastPath Guide—529443-001
Glossary-45
harmonic
harmonic. The sinusoidal component of an alternating-current (AC) voltage that is a
multiple of the waveform frequency.
harmonic distortion. Harmonics that change an alternating-current (AC) waveform from
sinusoidal to complex.
header. An object that, when specified for inclusion in a program’s source code, causes the
program to behave as if the statement including the header were actually a specific set
of other programming statements. A header contains coded information that provides
details (such as data item length) about the data that the header precedes.
In an Open System Services (OSS) program, a header is the name of a file known to
the run-time library used by a process. In a Guardian environment C language
program, a header is the file identifier for a file known to the run-time library used by a
process.
heat sink. A metal conductor specifically designed to absorb and dissipate excess heat.
HEF. Hardware error freeze.
hertz (Hz). A unit of frequency. One hertz equals one cycle/second.
high frequency. A Federal Communications Commission (FCC) designation for a
frequency in the range 30 through 300 megahertz, corresponding to a decametric
wave in the range 10 through 100 meters.
high PIN. A process identification number (PIN) that is greater than 255. Contrast with low
PIN.
hop count. The number of routers that form a route between a ServerNet source and
ServerNet destination. Hop count is used to determine the best route. If two alternate
routes have the same time factor, the path with the lower hop count is the better route.
host database. An SQL database maintained for the host system and containing
information about requests, software inputs, snapshots, targets, and profiles.
host system. (1) A computer system that supports very large databases and does batch
processing, usually for an entire network of smaller systems. (2) The central site on
which the Distributed Systems Management/Software Configuration Manager
(DSM/SCM) is managed, the Archive is maintained, and configuration revisions are
built. The host system is also a target system.
HP NonStop™ Cluster Switch (model 6770). An assembly that routes ServerNet
messages across an external fabric of a ServerNet cluster. The cluster switch consists
of a ServerNet II Switch, an uninterruptible power supply (UPS), and AC transfer
switch, and it can be packaged in a switch enclosure or in a 19-inch rack. The cluster
switch is used with star, split-star, and tri-star topologies. See also HP NonStop™
ServerNet Switch (model 6780).