ServerNet Cluster 6780 Operations Guide (G06.28+, H06.05+)

Glossary
ServerNet Cluster 6780 Operations Guide—525606-003
Glossary-3
cluster
cluster. (1) A collection of servers, or nodes, that can function either independently or
collectively as a processing unit. See also ServerNet cluster. (2) A term used to
describe a system in a Fiber Optic Extension (FOX) ring. More specifically, a FOX
cluster is a collection of processors and I/O devices functioning as a logical group. In
FOX nomenclature, the term is synonymous with system or node.
cluster number. A number that uniquely identifies a node in a FOX ring. This number can
range from 1 through 14. See also node number.
cluster switch. An assembly that routes ServerNet messages across an external fabric of a
ServerNet cluster. See HP NonStop Cluster Switch (model 6770) and HP NonStop
ServerNet Switch (model 6780).
cluster switch group. Within an external ServerNet fabric, all of the 6780 switches that
belong to the same cluster switch zone. The cluster switches within a group are
connected via four vertical tetrahedrons. A cluster switch group can consist of up to
four 6780 switches. All of the cluster switches that form a cluster switch group typically
are installed in the same cluster switch rack. See also cluster switch layer and cluster
switch zone.
cluster switch layer. The topological cluster switch position within a cluster switch group.
Each cluster switch group consists of four layers, numbered 1 to 4 from bottom to top.
A cluster switch layer is equivalent to a cluster switch and provides connections for up
to eight ServerNet nodes. See also cluster switch layer number.
cluster switch layer number. A number in the range 1 through 4 that identifies the position
of a cluster switch within a cluster switch group. See also cluster switch group.
cluster switch logic board. A circuit board that provides switching logic for the HP
NonStop ServerNet Switch (model 6780). The logic board (LB) has a front panel for
operator and maintenance functions.
cluster switch rack. A mechanical frame consisting of or based on a 19-inch rack that
supports the hardware necessary for a cluster switch group.
cluster switch zone. A pair of X-fabric and Y-fabric cluster switch groups and the ServerNet
nodes connected to them. The zone always contains two cluster switch groups with
the cluster switches on each fabric connected by intrazone cables. A cluster switch
zone can support up to 32 nodes.
CME. See correctable memory error (CME).
cold load. A synonym for system load or load (in the case of single processor load). System
load or load is the preferred term in this and other NonStop S-series system manuals.
See system image tape (SIT) and load.
command. A demand for action by or information from a subsystem or the operation
demanded by an operator or application. A command is typically conveyed as an
interprocess message from an application to a subsystem.