Storage Technology Definitions

This glossary explains the meaning of key words and phrases that information technology (IT) and business professionals use when discussing storage and related software products. You can find additional definitions by visiting WhatIs.com or using the search box below.

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    3D XPoint

    3D XPoint is memory storage technology that was jointly developed by Intel and Micron Technology. The two vendors intended for the technology to fill a gap in the storage market between dynamic RAM (DRAM) and NAND flash.

  • A

    address space

    Address space is the amount of memory allocated for all possible addresses for a computational entity -- for example, a device, a file, a server or a networked computer.

  • Advanced Host Controller Interface (AHCI)

    Advanced Host Controller Interface, or AHCI, is a technical standard for an interface that enables software to communicate with Serial ATA (SATA) devices.

  • archive

    An archive is a collection of data moved to a repository for long-term retention, to be kept separate for compliance reasons or moved off primary storage media.

  • B

    bad block

    A bad block is an area of storage media that is no longer reliable for storing and retrieving data because it has been physically damaged or corrupted.

  • bare-metal cloud

    Bare-metal cloud is a public cloud service that offers dedicated hardware resources without any installed operating systems or virtualization infrastructure.

  • bare-metal restore

    A bare-metal restore (also referred to as bare-metal recovery or bare-metal backup) is a data recovery and restoration process where a computer is restored to a new machine, typically after a catastrophic failure.

  • block storage

    Block storage is an approach to data storage in which each volume acts as an individual hard drive that is configured by the administrator.

  • business impact analysis (BIA)

    A business impact analysis (BIA) is a systematic process to determine and evaluate the potential effects of an interruption to critical business operations as a result of a disaster, accident or emergency.

  • byte

    In most computer systems, a byte is a unit of data that is eight binary digits long.

  • What is bit rot?

    Bit rot is the slow deterioration in the performance and integrity of data stored on storage media.

  • C

    cache

    A cache -- pronounced CASH -- is hardware or software that is used to store something, usually data, temporarily in a computing environment.

  • cache memory

    Cache memory is a chip-based computer component that makes retrieving data from the computer's memory more efficient.

  • charge-coupled device

    A charge-coupled device (CCD) is a light-sensitive integrated circuit that captures images by converting photons to electrons.

  • cloud archive

    A cloud archive is storage as a service for long-term data retention.

  • cloud data management

    Cloud data management is a way to manage data across cloud platforms, either with or instead of on-premises storage.

  • Cloud Data Management Interface (CDMI)

    The Cloud Data Management Interface (CDMI) is an international standard that defines a functional interface that applications use to create, retrieve, update and delete data elements from cloud storage.

  • cloud hosting

    Cloud hosting is the process of outsourcing an organization's computing and storage resources to a service provider that offers its infrastructure services in a utility model.

  • cloud storage

    Cloud storage is a service model in which data is transmitted and stored on remote storage systems, where it is maintained, managed, backed up and made available to users over a network (typically the internet).

  • cloud storage API

    A cloud storage API is an application programming interface that connects a locally based application to a cloud-based storage system so that a user can send data to it and access and work with data stored in it.

  • cloud storage provider

    A cloud storage provider, sometimes referred to as a managed service provider, is a company that offers organizations and individuals the ability to place and retain data in an off-site storage system.

  • cloud storage service

    A cloud storage service is a business that maintains and manages its customers' data and makes that data accessible over a network, usually the internet.

  • cloud washing

    Cloud washing (also spelled cloudwashing) is the purposeful and sometimes deceptive attempt by a vendor to rebrand an old product or service by associating the buzzword 'cloud' with it.

  • cold storage

    Cold storage is a computer system or mode of operation designed for the retention of inactive data.

  • Common Internet File System (CIFS)

    CIFS (Common Internet File System) is a protocol that gained popularity around the year 2000, as vendors worked to establish an Internet Protocol-based file-sharing protocol.

  • computational storage

    Computational storage is an IT architecture in which data is processed at the storage device level to reduce the amount of data that must move between the storage plane and the compute plane.

  • content-addressed storage (CAS)

    Content-addressed storage (CAS) -- also called content-addressable storage -- is a method for storing fixed content as objects and providing fast access to that content.

  • converged network adapter (CNA)

    A converged network adapter (CNA) is a single network interface device that provides the functionality of both a Fibre Channel (FC) host bus adapter (HBA) and a TCP/IP Ethernet network interface card (NIC).

  • copy data management (CDM)

    Copy data management (CDM) is an approach to reducing storage consumption that involves eliminating the unnecessary duplication of production data.

  • What is a clustered network-attached storage (NAS) system?

    A clustered network-attached storage (NAS) system is a scale-out storage platform made up of multiple NAS nodes networked together into a single cluster.

  • What is a CompactFlash card (CF card)?

    A CompactFlash card (CF card) is a memory card format developed by SanDisk in 1994 that uses flash memory technology to store data on a very small portable device.

  • What is Ceph?

    Ceph is an open source software solution that provides a unified system for enterprise-level object, block- and file-based storage.

  • What is cloud NAS (cloud network-attached storage)?

    Cloud NAS (network-attached storage) is remote storage that is accessed over the internet as if it is local.

  • What is continuous data protection (CDP)?

    Continuous data protection (CDP), also known as 'continuous backup,' is a backup and recovery storage system in which all the data in an enterprise is backed up whenever any change is made.

  • What is the Common Information Model (CIM)?

    The Common Information Model (CIM) is a computer industry standard that defines device and application characteristics so system administrators and management programs can control devices and applications from different manufacturers.

  • D

    data compression

    Data compression is a reduction in the number of bits needed to represent data.

  • data deduplication

    Data deduplication is a process that eliminates redundant copies of data and reduces storage overhead.

  • data destruction

    Data destruction is the process of destroying data stored on tapes, hard disks and other forms of electronic media so that it's completely unreadable and can't be accessed or used for unauthorized purposes.

  • data lifecycle management (DLM)

    Data lifecycle management (DLM) is a policy-based approach to managing the flow of an information system's data throughout its lifecycle: from creation and initial storage to when it becomes obsolete and is deleted.

  • dedicated cloud

    A dedicated cloud is a single-tenant cloud infrastructure, which essentially acts as an isolated, single-tenant public cloud.

  • DIMM (dual in-line memory module)

    DIMM, or dual in-line memory module, is a type of computer memory that is natively 64 bits, enabling fast data transfer.

  • direct access storage device (DASD)

    A direct access storage device (DASD) is a type of secondary storage device that supports direct access to the stored data, as opposed to sequential access, which is slower and less efficient.

  • disk array

    A disk array, also called a storage array, is a data storage system used for block-based storage, file-based storage or object storage.

  • disk mirroring (RAID 1)

    Disk mirroring, also known as RAID 1, is the replication of data across two or more disks.

  • DRAM (dynamic random access memory)

    DRAM (dynamic random access memory) is a type of semiconductor memory that is typically used for the data or program code needed by a computer processor to function.

  • What is a distributed file system (DFS)?

    A distributed file system (DFS) enables clients to access file storage from multiple hosts through a computer network as if they were accessing local storage.

  • What is data migration? Definition, strategy and best practices

    Data migration is the process of transferring data between data storage systems, data formats or computer systems.

  • What is direct-attached storage (DAS) and how does it work?

    Direct-attached storage (DAS) is a type of data storage that is attached directly to a computer without going through a network.

  • E

    email archiving

    Email archiving is a systematic approach to saving and protecting the data contained in emails to enable fast retrieval.

  • enterprise storage

    Enterprise storage is a centralized repository for business information that provides common data management, protection and sharing functions through connections to computer systems.

  • erasure coding (EC)

    Erasure coding (EC) is a method of data protection in which data is broken into fragments, expanded and encoded with redundant data pieces, and stored across a set of different locations or storage media.

  • exabyte (EB)

    An exabyte (EB) is a large unit of computer data storage, two to the sixtieth power bytes.

  • external storage device

    An external storage device, also referred to as auxiliary storage and secondary storage, is a device that contains all the addressable data storage that is not inside a computer's main storage or memory.

  • What is an embedded MultiMediaCard (eMMC)?

    An embedded MultiMediaCard (eMMC) is a small storage device made up of NAND flash memory and a storage controller.

  • F

    Fibre Channel (FC) port types

    A Fibre Channel port is a hardware pathway into and out of a node that performs data communications over an FC link.

  • file synchronization (file sync)

    File synchronization (file sync) is a method of keeping files that are stored in several different physical locations up to date.

  • file system

    In computing, a file system -- sometimes written filesystem -- is a logical and physical system for organizing, managing and accessing the files and directories on a device's solid-state drive (SSD), hard-disk drive (HDD) or other media.

  • flash solid-state drive (SSD)

    A flash solid-state drive (SSD) is a non-volatile storage device that stores persistent data in flash memory.

  • G

    garbage collection (GC)

    Garbage collection (GC) is a memory recovery feature built into programming languages such as C# and Java.

  • gibibyte (GiB)

    A gibibyte (GiB) is a unit of measure of capacity in computing.

  • gigabyte (GB)

    A gigabyte (GB) -- pronounced with two hard Gs -- is a unit of data storage capacity that is roughly equivalent to 1 billion bytes.

  • green cloud

    Green cloud refers to the potential environmental benefits that green IT services delivered over the internet can offer to individual companies and society as a whole.

  • H

    Hadoop as a service (HaaS)

    Hadoop as a service (HaaS), also known as Hadoop in the cloud, is a big data analytics framework that stores and analyzes data in the cloud using Hadoop.

  • hardware RAID (hardware redundant array of independent disk)

    Hardware RAID is a form of RAID (redundant array of independent disks) where processing is done on the motherboard or a separate RAID card.

  • HDD form factor (hard disk drive form factor)

    HDD form factor (hard disk drive form factor) is the size or geometry of a data storage device equipped with one or more magnetic-coated spinning platters and one or more moving actuator arms with magnetic heads to read and write information.

  • hierarchical storage management (HSM)

    Hierarchical storage management (HSM) is policy-based management of data files that uses storage media economically and without the user being aware of when files are retrieved from storage.

  • holographic storage (holostorage)

    Holographic storage is computer storage that uses laser beams to store computer-generated data in three dimensions.

  • host bus adapter (HBA)

    A host bus adapter (HBA) is a circuit board or integrated circuit adapter that connects a host system, such as a server, to a storage or network device.

  • hot plugging

    Hot plugging is the addition of a component to a running computer system without significant interruption to the operation of the system.

  • hybrid cloud storage

    Hybrid cloud storage is an approach to managing cloud storage that uses both local and off-site resources.

  • hybrid hard drive (HHD)

    A hybrid hard drive (HHD), sometimes known as a solid-state hybrid drive (SSHD), is a mass storage device that combines a conventional hard disk drive (HDD) and a NAND flash memory module.

  • What is a hard disk drive (HDD)?

    A computer hard disk drive (HDD) is a non-volatile data storage device.

  • I

    IDE (Integrated Drive Electronics)

    IDE (Integrated Drive Electronics) is an electronic interface standard that defines the connection between a bus on a computer's motherboard and the computer's disk storage devices.

  • information lifecycle management (ILM)

    Information lifecycle management (ILM) is a comprehensive approach to managing an organization's data and associated metadata, starting with its creation and acquisition through when it becomes obsolete and is deleted.

  • IOPS (input/output operations per second)

    IOPS (input/output operations per second) is the standard unit of measurement for the maximum number of reads/writes to noncontiguous storage locations.

  • iSCSI (Internet Small Computer System Interface)

    ISCSI is a transport layer protocol that describes how Small Computer System Interface (SCSI) packets should be transported over a TCP/IP network.

  • iSCSI initiator

    An Internet Small Computer System Interface initiator is software or hardware that lets a host computer send data to an external iSCSI-based storage array through an Ethernet network adapter over a TCP-based IP network.

  • J

    JBOD (just a bunch of disks)

    JBOD, which stands for 'just a bunch of disks,' is a type of multilevel configuration for disks.

  • JEDEC

    JEDEC is a global industry group that develops open standards for microelectronics.

  • K

    Kilo, mega, giga, tera, peta, exa, zetta and all that

    Kilo, mega, giga, tera, peta, exa and zetta are among the binary prefixes used to denote the quantity of something, such as a byte or bit in computing and telecommunications.

  • kilobyte (KB or Kbyte)

    A kilobyte (KB or Kbyte) is a unit of measurement for computer memory or data storage.

  • L

    litigation hold (legal hold, preservation order or hold order)

    A litigation hold -- also known as legal hold, preservation order or hold order -- is an internal process that an organization undergoes to preserve all data that might relate to a legal action involving the organization.

  • logical unit number (LUN)

    A logical unit number (LUN) is a unique identifier for designating an individual or collection of physical or virtual storage devices that execute input/output (I/O) commands with a host computer, as defined by the Small Computer System Interface (SCSI) standard.

  • LUN masking

    LUN masking is an authorization mechanism used in storage area networks (SANs) to make LUNs available to some hosts but unavailable to other hosts.

  • M

    mebibyte (MiB)

    A mebibyte (MiB) is a unit of measurement used in computer data storage.

  • megabyte (MB)

    A megabyte is a unit of data capacity that is equal to 1,000,000 bytes in decimal notation (base 10) or 1,048,576 bytes in binary notation (base 2).

  • mirror site

    A mirror site is a website or set of files on a computer server that has been copied to another computer server so that the site or files are available from more than one place.

  • MRAM (magnetoresistive random access memory)

    MRAM (magnetoresistive random access memory) is a method of storing data bits using magnetic states instead of the electrical charges used by devices such as dynamic random access memory (DRAM).

  • MTTR (mean time to repair)

    MTTR (mean time to repair) is the average time required to fix a failed component or device and return it to production status.

  • What is an mSATA SSD (mSATA solid-state drive)?

    An mSATA SSD is a solid-state drive that conforms to the mSATA interface specification developed by the Serial ATA (SATA) International Organization.

  • N

    N_Port ID virtualization (NPIV)

    N_Port ID virtualization (NPIV) is a Fibre Channel (FC) standard that makes it possible to create multiple virtual ports on a single physical node port (N_Port), with each virtual port appearing as a unique entity to the FC network.

  • NAND flash wear-out

    NAND flash wear-out is the breakdown of the oxide layer within the floating gate transistors of NAND flash memory.

  • nearline storage

    Nearline storage is the on-site storage of data on removable media.

  • Network Data Management Protocol (NDMP)

    Network Data Management Protocol (NDMP) is an open protocol to control data backup and recovery communications between primary and secondary storage in a heterogeneous network environment.

  • non-volatile memory (NVM)

    Non-volatile memory (NVM) is a type of computer storage medium that retains data even in the absence of a power supply.

  • NVRAM (non-volatile random access memory)

    NVRAM (non-volatile random access memory) refers to computer memory that can hold data even when power to the memory chips has been turned off.

  • What is an NVDIMM (non-volatile dual in-line memory module)?

    An NVDIMM (non-volatile dual in-line memory module) is hybrid computer memory that retains data during a service outage.

  • What is NetApp?

    NetApp, formerly Network Appliance, Inc., is a multinational corporation in the computer technologies industry specializing in data storage hardware, software and cloud services.

  • What is network-attached storage (NAS)? A complete guide

    Network-attached storage (NAS) is dedicated file storage that enables multiple users and heterogeneous client devices to retrieve data from centralized disk capacity.

  • What is NVMe over Fibre Channel (NVMe over FC)? Definition and Guide

    Non-volatile memory express over Fibre Channel (NVMe over FC) is a technology specification designed to enable NVMe-based message commands to transfer data and status information between a host computer and a target storage subsystem over a Fibre Channel network fabric.