NonStop System Glossary

Versatile I/O (VIO) enclosure
A self-contained, rackmountable enclosure that contains a logic board and supporting power,
cooling, maintenance, and interfacing components that provide I/O, processor, and gigabit
Ethernet connectivity.
vertical tetrahedron
A server topology in which the ServerNet connections between the layers of a cluster switch group
form a tetrahedron. See also tetrahedron, tetrahedral topology, and cluster switch layer.
VIO enclosure
See Versatile I/O (VIO) enclosure.
virtual file system
In UNIX and Open System Services (OSS), a file system that allows files of a fileset to be distributed
across several physical devices.
virtual private network (VPN)
When combined with IP security features such as authentication and content encryption, a method
for securing communications through the public Internet.
visiting interface
Interface resources that have migrated to their failover interface.
Visual Inspect
A symbolic debugger that runs on a Windows workstation. Visual Inspect is an independent product
bundled with the NonStop Enterprise Toolkit (ETK). Visual Inspect supports CISC (TNS), RISC
(TNS/R), and Itanium (TNS/E) machine architectures and compilers (that is, C, C++, COBOL, TAL,
and pTAL) in both the Guardian and HP NonStop Open System Services (OSS) execution
environments. Visual Inspect uses client-server architecture. The client runs on a Windows
workstation, and the server runs on the NonStop host.
volt (V)
The standard unit of measure of the potential difference that is required to move an electric charge.
volume
A logical disk, which can be one or two magnetic disk drives. Volumes have names that begin
with a dollar sign ($), such as $DATA. See also mirrored disk or volume.
voluntary rendezvous opportunity (VRO)
A point in the instruction stream of a processing element at which the operating system is permitted
to establish synchronization among the processor elements of a logical process. Most system calls
are VROs.
voting
Comparison of I/O output streams from one to three processing elements.
VPN
See virtual private network (VPN).
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