Primary Storage Devices Definitions

Search Definitions
  • 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.

  • C

    compact disc (CD)

    A compact disc is a portable storage medium that can record, store and play back audio, video and other data in digital form.

  • 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).

  • 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.

  • D

    Data Dynamics StorageX

    Data Dynamics StorageX is a software suite that specializes in data migration and Microsoft Distributed File System management.

  • direct access

    In computer storage, direct access is the process of reading and writing data on a storage device by going directly to where the data is physically located on the device rather than having to move sequentially from one physical location to the next to find the correct data.

  • 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.

  • E

    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.

  • F

    Fibre Channel

    Fibre Channel is a high-speed networking technology primarily used for transmitting data among data centers, computer servers, switches and storage at data rates of up to 128 Gbps.

  • 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.

  • Fibre Channel over Ethernet (FCoE)

    Fibre Channel over Ethernet (FcoE) is a storage protocol that enables Fibre Channel (FC) communications to run directly over Ethernet.

  • 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 memory card

    A flash memory card -- sometimes called a storage card -- is a small storage device that uses non-volatile semiconductor memory to store data on portable or remote computing devices.

  • floating gate transistor (FGT)

    A floating gate transistor (FGT) is a complementary metal-oxide semiconductor (CMOS) technology capable of holding an electrical charge in a memory device that is used to store data.

  • H

    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.

  • HD-DVD (high-definition DVD)

    HD-DVD (high-definition DVD) is a defunct high-capacity optical storage medium that was once seen as the successor to the DVD.

  • 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.

  • 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.

  • 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.

  • InfiniBand

    InfiniBand is an industry standard communications specification the InfiniBand Trade Association (IBTA) developed.

  • 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.

  • L

    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

    M.2 SSD

    An M.2 SSD is a small form factor solid-state drive (SSD) that internally mounted storage expansion cards use.

  • 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.

  • 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.

  • O

    optical storage

    Optical storage is any storage type in which data is written and read with a laser.

  • overprovisioning (SSD overprovisioning)

    Overprovisioning, in a storage context, is the inclusion of extra storage capacity in a solid-state drive.

  • oversubscription

    Oversubscription in a storage area network (SAN) is the practice of committing more network bandwidth to devices connected to that network than what is physically available.

  • What are optical disks and how do they work?

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

  • P

    parallel file system

    A parallel file system is a software component designed to store data across multiple networked servers.

  • What is a partition in computers?

    A partition is a logical division of a hard disk drive (HDD) that's treated as a separate unit by operating systems (OSes) and file systems.

  • What is pay-as-you-go cloud computing (PAYG cloud computing)?

    Pay-as-you-go cloud computing, or PAYG cloud computing, is a payment method for cloud computing that charges based on usage. The practice is similar to that of utility bills, using only resources that are needed.

  • Q

    queue depth

    Queue depth, in storage, is the number of pending input/output (I/O) requests that a storage resource can handle at any one time.

  • R

    RAID 3 (redundant array of independent disks 3)

    RAID 3 (redundant array of independent disks 3) is a RAID configuration that uses a parity disk to store the information generated by a RAID controller and uses striping to store the data.

  • RAID 4 (redundant array of independent disks)

    RAID 4 (redundant array of independent disks) is a RAID configuration that uses a dedicated parity disk and block-level striping across multiple disks.

  • RAID controller

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

  • What is 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 (SSDs) to protect data in the case of a drive failure.

  • What is 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 disk drives (HDDs) or solid-state drives (SSDs), in a redundant array of independent disks group.

  • What is RAID 5?

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

  • S

    SAN switch (storage area network switch)

    A SAN switch (storage area network switch) is a device that connects servers and shared pools of storage devices and is dedicated to moving storage traffic.

  • SATA Express (SATAe)

    SATA Express (SATAe or Serial ATA Express) is a bus interface to connect storage devices to a computer motherboard, supporting SATA and PCI Express protocols simultaneously.

  • SCSI (Small Computer System Interface)

    SCSI (Small Computer System Interface) is an electronic interface that enables PCs and servers to communicate with peripheral hardware, such as storage devices, printers and scanners, faster and more flexibly than previous parallel data transfer interfaces.

  • Serial ATA (Serial Advanced Technology Attachment or SATA)

    Serial ATA (Serial Advanced Technology Attachment or SATA) is a command and transport protocol that defines how data is transferred between a computer's motherboard and mass storage devices, such as hard disk drives (HDDs), optical drives and solid-state drives (SSDs).

  • Serial-Attached SCSI (SAS)

    Serial-Attached SCSI (SAS) is a method used to access computer peripheral devices that employs a serial -- one bit at a time -- means of digital data transfer over thin cables.

  • server-based storage

    Server-based storage is a re-emerging class of data storage that removes cost and complexity by housing storage media inside servers rather than in dedicated and custom-engineered storage arrays.

  • shingled magnetic recording (SMR)

    Shingled magnetic recording (SMR) is a technique for writing data to a hard disk drive (HDD) whereby the data tracks partially overlap to increase the areal density and overall storage capacity per disk.

  • software redundant array of independent disk (software RAID)

    Software RAID, also known as virtual RAID, is a form of RAID (software redundant array of independent disk) performed on an internal server.

  • storage filer

    A storage filer is a type of file server designed and programmed for high-volume data storage, backup and archiving.

  • storage volume

    A storage volume is an identifiable unit of data storage. It can be a removable hard disk, but it does not have to be a unit that can be physically removed from a computer or storage system.

  • What is SSD RAID (solid-state drive RAID)?

    SSD RAID (solid-state drive RAID) is a methodology commonly used to protect data by distributing redundant data blocks across multiple SSDs.

  • U

    unified storage

    Unified storage -- sometimes called network unified storage or multiprotocol storage -- is a storage system that enables users to run and manage files and applications from a single device.

  • V

    virtual LUN (virtual logical unit number)

    A virtual LUN (virtual logical unit number) is a representation of a storage area that is not tied to any physical storage allocation.

  • virtual SAN appliance (VSA)

    A virtual SAN appliance (VSA) is a software bundle that allows a storage manager to turn the unused storage capacity in his network's virtual servers into a storage area network (SAN).

  • W

    World Wide Name (WWN)

    A World Wide Name (WWN) is a unique identifier that is hard-coded into each Fibre Channel (FC) device by the device's manufacturer.

  • Z

    What is ZFS?

    ZFS is a local file system and logical volume manager created by Sun Microsystems to direct and control the placement, storage and retrieval of data in enterprise-class computing systems.