cluster
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Related to cluster: Cluster analysis, Cluster Headaches
cluster
1. Astronomy an aggregation of stars or galaxies moving together through space
2. Chem
a. a chemical compound or molecule containing groups of metal atoms joined by metal-to-metal bonds
b. the group of linked metal atoms present
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
cluster
A group of stars whose members are sufficiently close to each other to be physically associated. Clusters range from dense congregations of many thousands of stars to loose groups of only a few stars. Current theories of stellar evolution suggest that stars form in associations, whose densest groupings remain bound as clusters while the other stars disperse; this view is supported by the relatively well-defined Hertzsprung–Russell diagrams of clusters, which indicate that cluster members are of essentially the same composition and age (see also turnoff point). Because the stars in a cluster are all at approximately the same distance, the observed differences in appearance are believed to be due mainly to differences in mass. An estimate of distance is obtained from the technique of main-sequence fitting. See globular cluster; open cluster.Cluster
An ESA mission to study in three dimensions the shape and dynamic behavior of small-scale structures in the Earth's plasma environment. In effect, Cluster is examining ‘space weather’ – that is, the interaction between the particles of the solar wind and the Earth's magnetosphere. The mission consists of four identical 500-kg satellites, carrying the same 10 instruments. The satellites were carried into space in two pairs by Russian-made Soyuz rockets during the summer of 2000. The first pair, nicknamed Salsa and Samba, were launched July 16, followed by the second pair, Rumba and Tango, launched Aug. 9. The Cluster craft were scheduled to operate until 2005. The mission, which was designated Cluster II, was the replacement for an earlier failed mission. The original Cluster satellites were to have been sent into space together in June 1996, on an Ariane-5 rocket, but were destroyed when the rocket unexpectedly tilted and broke up soon after liftoff.Collins Dictionary of Astronomy © Market House Books Ltd, 2006
Cluster
Any configuration of elements that are grouped or gathered closely together.
Illustrated Dictionary of Architecture Copyright © 2012, 2002, 1998 by The McGraw-Hill Companies, Inc. All rights reserved
cluster
[′kləs·tər] (astronomy)
(computer science)
In a clustered file, one of the classes into which records with similar sets of content identifiers are grouped.
A grouping of hardware devices in a distributed processing system.
A group of disk sectors that is treated as a single entity by the operating system
(engineering)
A pyrotechnic signal consisting of a group of stars or fireballs.
A grouping of rocket motors fastened together.
(ordnance)
A collection of small bombs held together by an adapter for dropping.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
cluster
i. Several bomblets forming part of a bomb as in cluster bomb. Once a bomb is released from the aircraft, individual bomblets are dispensed by the bomb.
ii. Two or more parachutes linked to support a single load.
iii. Several engines controlled by a single throttle.
ii. Two or more parachutes linked to support a single load.
iii. Several engines controlled by a single throttle.
An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved
cluster
(architecture)Multiple servers providing the same
service. The term may imply resilience to failure and/or
some kind of load balancing between the servers. Compare
RAIS.
cluster
(file system)An elementary unit of allocation of a disk
made up of one or more physical blocks.
A file is made up of a whole number of possibly non-contiguous clusters. The cluster size is a tradeoff between space efficiency (the bigger is the cluster, the bigger is on the average the wasted space at the end of each file) and the length of the FAT.
A file is made up of a whole number of possibly non-contiguous clusters. The cluster size is a tradeoff between space efficiency (the bigger is the cluster, the bigger is on the average the wasted space at the end of each file) and the length of the FAT.
This article is provided by FOLDOC - Free Online Dictionary of Computing (foldoc.org)