NonStop System Glossary

hard link
In the Open System Services (OSS) file system, the relationship between two directory entries for
the same file. A hard link acts as an additional pointer to a file. A hard link cannot be used to
point to a file in another fileset. Contrast with symbolic link.
hard reset
An action performed on an HP NonStop Cluster Switch (model 6770) and HP NonStop ServerNet
Switch (model 6780) that reinitializes the router-2 ASIC within the switch, disrupting the routing
of ServerNet messages through the switch for several minutes. When the hard reset is finished, the
paths are restored automatically.
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.
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