Browse Definitions :
Definition

cluster

1) In a computer system, a cluster is a group of servers and other resources that act like a single system and enable high availability and, in some cases, load balancing and parallel processing. See clustering.

2) In personal computer storage technology, a cluster is the logical unit of file storage on a hard disk; it's managed by the computer's operating system. Any file stored on a hard disk takes up one or more clusters of storage. A file's clusters can be scattered among different locations on the hard disk. The clusters associated with a file are kept track of in the hard disk's file allocation table (FAT). When you read a file, the entire file is obtained for you and you aren't aware of the clusters it is stored in.

Since a cluster is a logical rather than a physical unit (it's not built into the hard disk itself), the size of a cluster can be varied. The maximum number of clusters on a hard disk depends on the size of a FAT table entry. Beginning with DOS 4.0, the FAT entries were 16 bits in length, allowing for a maximum of 65,536 clusters. Beginnning with the Windows 95 OSR2 service release, a 32-bit FAT entry is supported, allowing an entry to address enough clusters to support up to two terabytes of data (assuming the hard disk is that large!).

The tradeoff in cluster size is that even the smallest file (and even a directory itself) takes up the entire cluster. Thus, a 10-byte file will take up 2,048 bytes if that's the cluster size. In fact, many operating systems set the cluster size default at 4,096 or 8,192 bytes. Until the file allocation table support in Windows 95 OSR2, the largest size hard disk that could be supported in a single partition was 512 megabytes. Larger hard disks could be divided into up to four partitions, each with a FAT capable of supporting 512 megabytes of clusters.

3) In some products, a cluster is a group of terminals or workstations attached to a common control unit.

This was last updated in April 2006

Continue Reading About cluster

Join the conversation

1 comment

Send me notifications when other members comment.

Please create a username to comment.

In a NVR which hanged but the storage of previous records are available but further recording not done. How can I save that files and start recording without formatting hdds by using clusters.
Cancel

-ADS BY GOOGLE

File Extensions and File Formats

SearchCompliance

  • Whistleblower Protection Act

    The Whistleblower Protection Act of 1989 is a law that protects federal government employees in the United States from ...

  • smart contract

    A smart contract, also known as a cryptocontract, is a computer program that directly controls the transfer of digital currencies...

  • risk map (risk heat map)

    A risk map, also known as a risk heat map, is a data visualization tool for communicating specific risks an organization faces. A...

SearchSecurity

  • certificate authority (CA)

    A certificate authority (CA) is a trusted entity that issues digital certificates, which are data files used to cryptographically...

  • hacktivism

    Hacktivism is the act of hacking, or breaking into a computer system, for a politically or socially motivated purpose.

  • advanced persistent threat (APT)

    An advanced persistent threat (APT) is a prolonged and targeted cyberattack in which an intruder gains access to a network and ...

SearchHealthIT

  • Cerner Corp.

    Cerner Corp. is a public company in North Kansas City, Mo., that provides various health information technologies, ranging from ...

  • clinical decision support system (CDSS)

    A clinical decision support system (CDSS) is an application that analyzes data to help healthcare providers make decisions and ...

  • Health IT (health information technology)

    Health IT (health information technology) is the area of IT involving the design, development, creation, use and maintenance of ...

SearchDisasterRecovery

  • tabletop exercise (TTX)

    A tabletop exercise (TTX) is a disaster preparedness activity that takes participants through the process of dealing with a ...

  • risk mitigation

    Risk mitigation is a strategy to prepare for and lessen the effects of threats faced by a data center.

  • ransomware recovery

    Ransomware recovery is the process of resuming options following a cyberattack that demands payment in exchange for unlocking ...

SearchStorage

  • SSD (solid-state drive)

    An SSD (solid-state drive) is a type of nonvolatile storage media that stores persistent data on solid-state flash memory.

  • file system

    In a computer, a file system -- sometimes written filesystem -- is the way in which files are named and where they are placed ...

  • storage virtualization

    Storage virtualization is the pooling of physical storage from multiple storage devices into what appears to be a single storage ...

Close