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.

Search Definitions
  • N

    NAS accelerator

    A NAS accelerator (network-attached storage accelerator) is a printed circuit card that offloads TCP/IP processing from a microprocessor.

  • NAS Appliance

    NAS appliances are commodity hardware that includes their own dedicated storage disks and RAID that can easily scale as more capacity is needed.

  • NAS enclosure (network-attached storage enclosure)

    NAS enclosures provide shared storage to all users connected to a network, and vary in models appropriate for home offices to enterprises.

  • NAS filer (network-attached storage filer)

    NAS filers add scalable, expandable storage for file-serving purposes in data sharing, cloud applications, Internet and enterprise networks, in both Fibre Channel SANs and Ethernet LANs.

  • NDMP (Network Data Management Protocol)

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

  • nearline storage

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

  • NetApp

    NetApp, formerly Network Appliance Inc., is a company in the computer technologies industry specializing in data storage hardware and associated management software.

  • NetApp Data Fabric

    The products and services that compose NetApp’s Data Fabric are designed to provide customers with the agility they need to quickly and efficiently move data to and from the cloud.

  • NetApp SolidFire

    NetApp SolidFire is a business division of NetApp Inc. that specializes in all-flash storage systems.

  • network-attached storage (NAS)

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

  • non-disruptive data migration

    Non-disruptive data migration is a feature that allows data movement from one storage device to another without causing downtime in the environment.

  • non-disruptive upgrade (NDU)

    A non-disruptive upgrade (NDU) is an update to software or hardware done without interruption to system service or data access.

  • non-volatile memory (NVM)

    Non-volatile memory (NVMe) is a semiconductor technology that does not require a continuous power supply to retain the data or program code stored in a computing device.

  • non-volatile storage (NVS)

    Non-volatile storage (NVS) is a broad collection of technologies and devices that do not require a continuous power supply to retain data or program code persistently on a short- or long-term basis.

  • NOR flash memory

    NOR flash memory is one of two types of non-volatile storage technologies.

  • 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.

  • NVMe (non-volatile memory express)

    NVMe (non-volatile memory express) is a host controller interface and storage protocol created to accelerate the transfer of data between enterprise and client systems and solid-state drives over a computer's high-speed PCIe bus.

  • NVMe over Fabrics (NVMe-oF)

    NVMe over Fabrics, also known as NVMe-oF and non-volatile memory express over fabrics, is a protocol specification designed to connect hosts to storage across a network fabric using the NVMe protocol.

  • NVMe over Fibre Channel (NVMe over FC) or FC-NVMe standard

    Nonvolatile memory express over Fibre Channel (NVMe over FC) -- which is implemented through the Fibre Channel-NVMe (FC-NVMe) standard -- 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.

  • 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.

  • O

    object storage

    Object storage, also called object-based storage, is an approach to addressing and manipulating units of storage called objects, in which files and metadata are combined.

  • ODCA (Open Data Center Alliance)

    The Open Data Center Alliance (ODCA) is an independent information technology (IT) consortium whose goal is to develop a unified vision of cloud requirements.

  • ODX (Offloaded Data Transfer)

    Offloaded Data Transfer (ODX) is a feature in Microsoft Windows Server 2012 that speeds up copy and move operations by allowing them to be performed by the storage hardware rather than the operating system.

  • open source cloud storage

    Open source cloud storage is a cloud storage architecture that uses freely available source code to build and manage a private cloud storage platform.

  • open source storage

    Open source storage is data storage software developed in a public, collaborative manner that permits the free use, distribution and modification of the source code.

  • OpenNebula

    OpenNebula is an open source management tool that helps virtualized data centers enable private clouds, public clouds and hybrid clouds.

  • OpenStack Swift

    OpenStack Swift, also known as OpenStack Object Storage, is an open source object storage system that is licensed under the Apache 2.0 license and runs on standard server hardware.

  • OpenZFS

    OpenZFS is an open-source file system and logical volume manager for highly scalable storage with built-in features such as replication, deduplication, compression, snapshots, and data protection.

  • optical disc

    An optical disc is an electronic data storage medium that can be written to and read from using a low-powered laser beam.

  • optical media

    Optical media - such as the compact disk (CD) - are storage media that hold content in digital form and that are written and read by a laser; these media include all the various CD and DVD variations, as well as optical jukeboxes and autochangers.

  • optical storage

    Optical storage is any storage type in which data is written and read with a laser. Typically, data is written to optical media, such as compact discs (CDs) and DVDs.

  • Orange Book

    Orange Book is the informal name for Philips and Sony's Recordable CD Standard.

  • orthogonal

    Orthogonal concepts have their roots in advanced mathematics. They are also associated with software development, storage and networking.

  • overprovisioning (SSD overprovisioning)

    Overprovisioning, in a storage context, is the inclusion of extra storage capacity in a flash solid state drive (SSD). The extra capacity is not visible to the host as available storage.

  • oversubscription

    Oversubscription, in a SAN (storage area network) switching environment, is the practice of connecting multiple devices to the same switch port to optimize switch use... (Continued)

  • P

    P/E cycle

    A solid-state-storage program-erase cycle is a sequence of events in which data is written to solid-state NAND flash memory cell (such as the type found in a so-called flash or thumb drive), then erased, and then rewritten.

  • packet writing

    Packet writing is a technology that enables the writing of data to a recordable compact disk (CD-R) incrementally, in multiple small blocks of data, rather than in a single block (as in disk-at-once recording), or in blocks defined by tracks (as in track-at-once recording), the other two common methods.

  • Panasas

    Panasas is a scale-out NAS (network-attached storage) vendor that produces hardware and software for demanding technical and enterprise environments.

  • parallel file system

    A parallel file system is a software component designed to store data across multiple networked servers and to facilitate high-performance access through simultaneous, coordinated input/output operations (IOPS) between clients and storage nodes.

  • parallel I/O

    Parallel I/O is a way of performing multiple input/output operations concurrently, rather than serially.

  • parity

    Parity is a method of detecting errors in data transmissions between computers, while parity bit and parity checking are used in RAID technology to guard against data loss.

  • partition

    Partitioning a hard disk drive is the first step in preparing it for data storage. A disk partition is a carved out logical space used to manage operating systems and files.

  • pay-as-you-go cloud computing (PAYG cloud computing)

    The pay-as-you-go cloud computing (PAYG cloud computing) method charges users only for the services they use, eliminating wasted resources.

  • pay-as-you-grow pricing

    Vendors that offer a pay-as-you-grow storage allow customers with growing environments to acquire capacity after an array has been installed through the purchase of licenses.

  • PCIe SSD (PCIe solid-state drive)

    A PCIe SSD (PCIe solid-state drive) is a high-speed expansion card that attaches a computer to its peripherals.

  • pebibyte (PiB)

    A pebibyte (PiB) is a unit of measure used to describe data capacity.

  • persistent storage

    Persistent storage is any data storage device that retains data after power to that device is shut off. It is also sometimes referred to as non-volatile storage.

  • personal cloud storage (PCS)

    Personal cloud storage (PCS) is a local network-attached storage (NAS) device that lets users store data, photos, music, videos and other files and is optimized for media streaming.

  • petabyte

    A petabyte is a measure of memory or data storage capacity that is equal to 2 to the 50th power of bytes. It's now common to see individual companies or even single storage systems with more than a petabyte of storage capacity.

  • phase change

    Phase change is a type of compact disk (CD) recording technology that enables the disks to be written, erased, and rewritten through the use of a layer of a special material (called the phase change layer) that can be changed repeatedly from an amorphous (formless) to a crystalline state, or phase-through exposure to variably-powered laser beams.

  • pipeline burst cache

    A pipeline burst cache is a cache or storage area for a computer processor that is designed to be read from or written to in a pipelining succession of four data transfers (or bursts) in which later bursts can start to flow or transfer before the first burst has arrived at the processor.

  • pixie dust or antiferromagnetically-coupled (AFC) media

    Pixie dust is the informal name that IBM is using for its antiferromagnetically-coupled (AFC) media technology, which can increase the data capacity of hard drives to up to four times the density possible with current drives.

  • PLEDM (phase-state low electron drive memory)

    PLEDM (phase-state low electron drive memory) is a new memory microchip technology that offers vastly greater capacity than memory devices commonly used in the past.

  • pNFS (Parallel NFS)

    The Parallel Network File System (pNFS) is part of the NFS v4.1 protocol that allows compute clients to access storage devices directly and in parallel.

  • point-in-time snapshot (PIT snapshot)

    Point-in-time snapshots are a method of data protection that allows an administrator to make a full copy of a volume so that a restore can occur based on a specific time.

  • portability

    Portability is a characteristic attributed to a computer program if it can be used in an operating systems other than the one in which it was created without requiring major rework.

  • primary storage (main storage)

    Primary storage is the collective methods and technologies used to capture and retain digital information that is in active use and critical for an organization’s operations.

  • private cloud storage (internal cloud storage)

    Private cloud storage, also called internal cloud storage, is a service delivery model for storage within a large enterprise.

  • production data

    Production data is data that is persistently stored and essential to completing day-to-day business tasks and processes.

  • protected mode

    Protected mode is a mode of program operation in a computer with an Intel-based microprocessor in which the program is restricted to addressing a specific contiguous area of 640 kilobytes.

  • public cloud storage

    Public cloud storage, also called storage-as-a-service or online storage is a service model that provides data storage on a pay-per-use basis, similar to the way a public utility like electric or gas provides and charges for services.

  • Pure Storage

    Pure Storage is a provider of enterprise data flash storage solutions designed to substitute for electromechanical disk arrays.

  • Purple Book

    The Purple Book is the informal name for Philips and Sony's specification document for the double-density compact disk (DDCD) format.

  • Q

    QLC NAND

    QLC NAND (quad-level cell NAND) is a form of NAND flash memory that can store up to four bits of data per memory cell.

  • QNAP Systems Inc. (Quality Network Appliance Provider Systems Inc.)

    QNAP Systems Inc. is a Taiwanese-based storage vendor specializing in hardware systems for file sharing, storage management, virtualization and cloud services as well as surveillance applications for home and businesses.

  • queue depth

    Queue depth, in storage, is the number of pending input/output (I/O) requests for a volume.

  • Quiz: Data Storage

    Computer storage is the holding of data in an electromagnetic form for access by a computer processor.

  • Qumulo

    Qumulo is a Seattle-based storage vendor that specializes in selling its data-aware storage software application called the Qumulo Core. This product provides detailed data analytics, and these analytics are meant to help customers better manage their data storage.

  • R

    race condition

    A race condition is an undesirable situation that occurs when a device or system attempts to perform two or more operations at the same time, but because of the nature of the device or system, the operations must be done in the proper sequence to be done correctly.

  • rack-scale flash

    Rack-scale flash is flash-only storage that uses a high-speed interface to connect the storage more directly to the CPU than with a traditional storage array.

  • Rackspace Cloud

    Cloud provider Rackspace offers several different cloud storage services including Cloud Files, Cloud Block Storage and Cloud Backup.

  • RADOS (Reliable Autonomic Distributed Object Store)

    Reliable Autonomic Distributed Object Store (RADOS) is an object storage service with the ability to scale to thousands of hardware devices by making use of management software that runs on each of the individual nodes. RADOS is an integral part of the Ceph distributed storage system.

  • RADOS Block Device (RBD)

    A RADOS Block Device (RBD) is software that facilitates the storage of block-based data in the open source Ceph distributed storage system.

  • RAID (redundant array of independent disks)

    RAID (redundant array of independent disks) is a way of storing the same data in different places on multiple hard disks or solid-state drives to protect data in the case of a drive failure.

  • RAID 0 (disk striping)

    RAID 0 (disk striping) is the process of dividing a body of data into blocks and spreading the data blocks across multiple storage devices, such as hard disks or solid-state drives (SSDs), in a redundant array of independent disks (RAID) group.

  • RAID 10 (RAID 1+0)

    RAID 10, also known as RAID 1+0, is a RAID configuration that combines disk mirroring and disk striping to protect data.

  • RAID 2

    RAID 2 is a technique that stripes data at the bit level using a Hamming code to detect errors.

  • RAID 3 (redundant array of independent disks)

    RAID 3 is a RAID configuration that uses striping and parity, but it uses a parity disk to store the parity information generated by a RAID controller instead of striping it with the data.

  • RAID 4 (redundant array of independent disks)

    RAID 4 is a RAID configuration that uses a dedicated parity disk and block-level striping across multiple disks.

  • RAID 5

    RAID 5 is a redundant array of independent disks configuration that uses disk striping with parity.

  • RAID 50 (RAID 5+0)

    RAID 50, also known as RAID 5+0, combines distributed parity (RAID 5) with striping (RAID 0).

  • RAID 6 (redundant array of independent disks)

    RAID 6, also known as double-parity RAID, uses two parity stripes on each disk. It allows for two disk failures within the RAID set before any data is lost.

  • RAID 7 (redundant array of independent disks)

    RAID 7 is a trademarked RAID level owned by the now defunct Storage Computer Corp. It is a non-standard RAID level that requires proprietary hardware.

  • RAID controller

    A RAID controller is a hardware device or software program used to manage hard disk drives (HDDs) or solid-state drives (SSDs) in a computer or storage array so they work as a logical unit.

  • RAID rebuild

    A RAID rebuild is the data reconstruction process that occurs in a redundant array of independent disks (RAID) implementation when a hard disk drive fails.

  • RAM (Random Access Memory)

    RAM (Random Access Memory) is the hardware in a computing device where the operating system (OS), application programs and data in current use are kept so they can be quickly reached by the device's processor.

  • RAM-based solid state drive (SSD)

    A RAM-based solid state drive is a storage device that is made from silicon microchips, has no moving parts and stores data electronically instead of magnetically.

  • RAMAC

    (IBM had an earlier system called RAMAC. See RAMAC (original).

  • RAMAC (random access method of accounting and control)

    RAMAC (which stood for 'random access method of accounting and control') was the world's first computer disk storage system... (Continued)

  • RAS (row address strobe)

    In computer memory technology, RAS (row address strobe) is a signal sent to a dynamic random access memory (DRAM) that tells it that an associated address is a row address.

  • RDRAM (Rambus DRAM)

    Rambus Dynamic Random Access Memory, or RDRAM (Rambus DRAM), is a type of computer device active memory developed and licensed by Rambus Inc.

  • read cache

    A read cache is a computer storage component that temporarily keeps a copy of data from a slower permanent storage location in order to accelerate the fulfillment of future requests for the data.

  • read-intensive SSD (read-intensive solid-state drive)

    A read-intensive solid-state drive (SSD) is a NAND flash-based storage or caching device used with applications that write data infrequently, in contrast to SSDs that target write-intensive workloads.

  • recordable DVD (writable DVD)

    Recordable DVD (sometimes called writable DVD) is a DVD technology that allows a PC user to write data one or more times to a DVD with the PC's DVD drive.

  • recovery

    In data management, recovery is a process that involves copying backup files from secondary storage (tape, Zip disk or other backup media) to hard disk.

  • Red Book

    The Red Book is the 1980 document that provides the specifications for the standard compact disc (CD) developed by Sony and Philips.

  • Red Hat OpenStack Platform

    Red Hat OpenStack Platform is a commercially supported distribution of open source OpenStack software designed to build and manage large pools of compute, storage and networking resources in public and private clouds.

  • redundant

    Redundancy can have several meanings, but commonly refers to spare hardware that is kept online or to duplicate data.

  • Remote Direct Memory Access (RDMA)

    Remote Direct Memory Access (RDMA) is a technology that allows computers in a network to exchange data in main memory without involving the processor, cache or OS.

  • RIMM

    In a computer, a RIMM is a memory module developed by Kingston Technology Corp.

-ADS BY GOOGLE

SearchDisasterRecovery

SearchDataBackup

SearchConvergedInfrastructure

Close