The term cluster is used in various contexts in operating systems, computing, storage technology and mobile communications.
- In the computing world, a cluster is understood to be a group of interconnected stand-alone computers that behave like a virtual processor. Accordingly, a cluster consists of at least two nodes that are interconnected via the Scalable Coherent Interface( SCI), via Gigabit Ethernet or Inifiniband. Depending on the application, a distinction is made between high availability clusters( HAC), high performance clusters( HPC), parallel clusters, throughput clusters and failover clusters. However, they can also be several computers - these can be standard PCs, workstations, servers or even supercomputers - which are connected to each other by means of load balancing in order to improve reliability, availability, serviceability, performance, scaling or throughput. Such clusters share resources and use special software to coordinate the activities of the individual components.
- The term cluster has also been used in terminal networks. In these network concepts, the cluster controller forms a computing unit that controls a group of terminals or workstations.
- In mobile communications, a cluster is understood to be a contiguous group of radio cells that makes full use of the available frequency spectrum once.
- In the case of hard disks and floppy disks, a cluster is the grouping of one or more consecutive sectors of a floppy disk into a logical unit that is jointly managed by the operating system. A cluster is located on a track and, as with a file allocation table, a File Allocation Table( FAT), can consist of 8 sectors like FAT32, which corresponds to 4 KB.