Data Center Definitions

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

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  • #

    64-bit processor (64-bit computing)

    A 64-bit processor refers to a microprocessor that can process data and instructions in chunks of 64 bits.

  • A

    abend (abnormal end)

    An abend (abnormal end) is an unexpected or abnormal termination of an application or operating system that results from a problem with the software.

  • ambient temperature

    Ambient temperature is the air temperature of any object or environment where equipment is stored.

  • ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers)

    ASHRAE was formed in 1959 by the merger of the American Society of Heating and Air-Conditioning Engineers (ASHAE), founded in 1894, and the American Society of Refrigerating Engineers (ASRE), founded in 1904.

  • assembler

    An assembler is a computer program that takes in basic instructions and converts them into a pattern of bits that the computer's processor can use to perform basic operations.

  • What is an automatic transfer switch?

    An automatic transfer switch (ATS) is a device that automatically transfers a power supply from its primary source to a backup source when it senses a failure or outage in the primary source.

  • B

    baffle

    In data center hot aisle containment, a baffle is anything that disturbs the flow of air through a room, rack or system. A baffle changes the course of airflow or re-directs it.

  • Basic Assembler Language (BAL)

    BAL (Basic Assembler Language) is a version of IBM's assembler language (sometimes called assembly language) for its System/360 and System/370 mainframe operating system.

  • blade server

    A blade server, sometimes referred to as a high-density server, is a compact device containing a computer used to manage and distribute data in a collection of computers and systems, called a network.

  • boot loader (boot manager)

    A boot loader (boot manager) is a small program that places the operating system (OS) of a computer into memory.

  • Bourne shell

    The Bourne shell is the original Unix shell -- command execution program, often called a command interpreter -- that was developed in 1979 at what at the time was Bell Labs.

  • brownfield (brownfield deployment, brownfield site)

    A brownfield deployment, in information technology, is the installation and configuration of new hardware or software that must coexist with legacy IT systems.

  • building management system

    A building management system (BMS) is a control system that can be used to monitor and manage the mechanical, electrical and electromechanical services in a facility.

  • What is Bash (Bourne Again Shell)?

    Bash (Bourne Again Shell) is the free and enhanced version of the Bourne shell distributed with Linux and GNU operating systems.

  • C

    capacity on demand (COD)

    Capacity on demand (COD) is a purchasing option that allows companies to receive equipment with more computer processing, storage or other capacity than the company needs at the time of purchase, and have that extra capacity remain unused and unpaid for until the company actually requires it.

  • Categories of twisted-pair cabling systems

    A twisted-pair cabling system is a cable consisting of one or several pairs of copper wires.

  • CICS (Customer Information Control System)

    CICS (Customer Information Control System) is middleware that sits between the z/OS IBM mainframe operating system and business applications.

  • colocation (colo)

    A colocation facility (colo) is a data center or telecommunications facility in which a business can rent space for servers, storage devices, and other computing and networking hardware.

  • computer room air handler (CRAH)

    A computer room air handler (CRAH) is a device used frequently in data centers to deal with the heat produced by equipment.

  • configuration management database (CMDB)

    A configuration management database (CMDB) is a file -- usually in the form of a standardized database -- that contains all relevant information about the hardware and software components used in an organization's IT services and the relationships among those components.

  • converged infrastructure

    Converged infrastructure, sometimes called 'converged architecture,' is an approach to data center management that packages compute, networking, servers, storage and virtualization tools into a prequalified set of IT hardware.

  • crontab

    Crontab is a Unix command that creates a table or list of commands, each of which is to be executed by the operating system (OS) at a specified time and on a regular schedule.

  • Cygwin

    Cygwin is a collection of open source tools that allows Unix or Linux applications to be compiled and run on a Microsoft Windows operating system (OS) from within a Linux-like interface.

  • What are COTS, MOTS, GOTS and NOTS?

    COTS, MOTS, GOTS and NOTS are abbreviations that describe prepackaged software or -- less commonly -- hardware purchase alternatives. The four acronyms denote different classifications of software and hardware, each with its own unique characteristics and usage scenarios.

  • What is computer room air conditioning (CRAC)? CRAC vs. CRAH unit differences?

    A computer room air conditioning (CRAC) unit is a device that monitors and maintains the temperature, air distribution and humidity in a data center, network or server room.

  • What is continuous modeling (data center continuous modeling)?

    Continuous modeling is an approach to data center management that supplements infrastructure management (DCIM) tools with engineering simulation tools.

  • D

    data center

    A data center is a facility composed of networked computers, storage systems and computing infrastructure that organizations use to assemble, process, store and disseminate large amounts of data.

  • data center as a service (DCaaS)

    Data center as a service (DCaaS) is the provision of off-site physical data center facilities and infrastructure to clients.

  • data center capacity planning

    Data center capacity planning ensures that an IT organization has enough facility space, power and computing resources to support average and peak workloads.

  • data center chiller

    A data center chiller is a cooling system used in a data center to remove heat from one element and deposit it into another element. Chillers are used by industrial facilities to cool the water used in their heating, ventilation and air-conditioning (HVAC) units. (Continued...)

  • data center infrastructure efficiency (DCiE)

    Data Center Infrastructure Efficiency (DCiE) is a metric used to determine the energy efficiency of a data center. The metric, which is expressed as a percentage, is calculated by dividing IT equipment power by total facility power.

  • data center management

    Data center management refers to the set of tasks and activities handled by an organization for the day-to-day requirements of operating a data center.

  • data center resiliency

    Resiliency is the ability of a server, network, storage system or an entire data center to recover quickly and continue operating even when there has been an equipment failure, power outage or other disruption.

  • data center services

    Data center services provide the supporting components necessary to the proper operation of a data center.

  • data integrity

    Data integrity is the assurance that digital information is uncorrupted and can only be accessed or modified by those authorized to do so.

  • DataCore

    DataCore is a software-defined storage (SDS) company, as well as an early storage virtualization software vendor, in Fort Lauderdale, Fla.

  • Debian

    Debian is a popular and freely available computer operating system (OS) that uses a Unix-like kernel -- typically Linux -- alongside other program components, many of which come from GNU Project.

  • Dell EMC VxRail

    Dell EMC VxRail is a hyper-converged appliance. Like VSPEX Blue -- the Dell EMC product that it replaced -- and other hyper-converged infrastructure (HCI) systems, VxRail includes compute, storage, networking and virtualization resources in a single device.

  • DRBD (Distributed Replicated Block Device)

    DRBD (Distributed Replicated Block Device) is a Linux-based software component that facilitates the replacement of shared storage systems by networked mirroring. DRBD makes it possible to maintain consistency of data among multiple systems in a network. DRBD also ensures high availability (HA) for Linux applications... (Continued)

  • ducting (data center cooling)

    Ducting is an approach to air management that uses a series of metal or plastic pipes to carry heated or cooled air from one place to another.

  • What is a data center administrator (DCA)?

    A data center administrator (DCA) is an experienced IT professional who is responsible for overseeing data center operations.

  • What is data center infrastructure management (DCIM)?

    Data center infrastructure management (DCIM) is the convergence of IT infrastructure, operations and building facilities functions within an organization.

  • E

    e-cycling

    E-cycling, also known as 'electronic recycling,' is the reuse or recycling of used electronic materials to limit e-waste.

  • economizer

    An economizer is a mechanical device that reduces the amount of energy used to cool a data center or other buildings.

  • edge data center

    An edge data center is a small data center that is located close to the edge of a network.

  • Electric plugs for each country

    Discover the electrical plugs, outlets and voltages used in different countries around the world.

  • Electronic Data Interchange (EDI)

    Electronic Data Interchange (EDI) is the transfer of data from one computer system to another by standardized message formatting without the need for human intervention.

  • emergency power off (EPO) button

    The emergency power off button, also called an EPO switch or EPO panel, is a safety measure for quickly disconnecting electrical power to a particular piece of equipment or facility in the event of an emergency.

  • Energy Star

    Energy Star is a government-backed labeling program that helps people and organizations save money and reduce greenhouse gas emissions by identifying factories, office equipment, home appliances and electronics that have superior energy efficiency.

  • epoch

    In a computing context, an epoch is the date and time relative to which a computer's clock and timestamp values are determined.

  • Evaluation Assurance Level (EAL)

    An Evaluation Assurance Level (EAL) is a category ranking assigned to an IT product or system after a Common Criteria security evaluation.

  • What is edge computing? Everything you need to know

    Edge computing is a distributed information technology (IT) architecture in which client data is processed at the periphery of the network, as close to the originating source as possible.

  • F

    Fedora

    Fedora, also known as Fedora Linux, is a popular open source Linux-based operating system (OS).

  • field-replaceable unit (FRU)

    In electronic hardware, particularly computer systems, a field-replaceable unit (FRU) is a circuit board or part that can be easily removed and replaced by the user or technician without having to send the product or system to a repair facility.

  • free cooling

    Free cooling is an approach to lowering the air temperature in a building or data center by using naturally cool air or water instead of mechanical refrigeration.

  • Fujitsu Ltd.

    Fujitsu Ltd. is a Japanese technology company that specializes in consumer and industrial electronics. Fujitsu’s products include servers, PCs, laptops, media centers, tablets, storage hardware, displays, air conditioning and heat pump units.

  • NetApp FlexPod

    NetApp FlexPod is a reference architecture for server, storage and networking components that are pretested and validated to work together as an integrated infrastructure stack.

  • G

    GNOME (GNU Network Object Model Environment)

    GNOME (GNU Network Object Model Environment) is a graphical user interface (GUI) and set of computer desktop applications for Linux operating system (OS) users.

  • GNU General Public License (GNU GPL or GPL)

    The GNU General Public License, often shortened to GNU GPL (or simply GPL), lists terms and conditions for the copying, modification and redistribution of open source software.

  • GNU/Linux

    GNU/Linux is a Unix-like operating system made up of different OS components and services that create the Linux OS.

  • grid computing

    Grid computing is a system for connecting a large number of computer nodes into a distributed architecture that delivers the compute resources necessary to solve complex problems.

  • gzip (GNU zip)

    Gzip (GNU zip) is a free and open source algorithm for file compression. The software is overseen by the GNU project.... (Continued)

  • What is a green data center?

    A green data center is a repository for the storage, processing, management and dissemination of data in which the physical space and the mechanical and electrical subsystems are designed to maximize energy efficiency and minimize the environmental impact.

  • What is green computing?

    Green computing, also known as sustainable computing, is the use of computers and other computing devices and equipment in energy-efficient and eco-friendly ways.

  • H

    hardware clustering

    Hardware clustering, sometimes called OS clustering, is a hardware-based method of turning multiple servers into a cluster -- a group of servers that acts like a single system.

  • heartbeat (computing)

    In computing, a heartbeat is a program that runs specialized scripts automatically whenever a system is initialized or rebooted.

  • high-performance computing

    High-performance computing (HPC) is the practice of using parallel data processing to improve computing performance and perform complex calculations.

  • HVAC (heating, ventilation and air conditioning)

    HVAC stands for heating, ventilation and air conditioning.

  • hyperconverged appliance (HCI appliance)

    A hyperconverged appliance (HCI appliance) is a hardware device that provides multiple data center management technologies within a single box.

  • HyperGrid

    HyperGrid is a cloud computing provider that offers Infrastructure as a Service (IaaS), Platform as a Service (PaaS) and application management services. To support the DevOps movement which breaks down the silos between software development and operations teams, HyperGrid can provide support for application lifecycle management (ALM) as well as virtual machine (VM), bare metal and container deployments.

  • What are hot and cold aisles in the data center?

    Hot and cold aisles in the data center are part of an energy-efficient layout for server racks and other computing equipment.

  • What is high availability (HA)? Definition and guide

    High availability (HA) is the ability of a system to operate continuously for a designated period of time even if components within the system fail.

  • What is Hitachi Vantara?

    Hitachi Vantara is a data storage systems provider, previously known as Hitachi Data Systems (HDS).

  • What is hot spot/cold spot?

    A hot spot/cold spot is an undesirable, tightly focused local temperature variation that often occurs when data center equipment is improperly cooled.

  • What is hyperconverged infrastructure? Guide to HCI

    Hyperconverged infrastructure is a software-centric architecture that tightly integrates compute, storage and virtualization resources in a single system that usually consists of x86 hardware.

  • What is hyperconverged storage?

    Hyperconverged storage is a software-defined approach to storage management that combines storage, compute, virtualization and networking technologies in one physical unit that's managed as a single virtualized system.

  • I

    IBM IMS (Information Management System)

    IBM IMS (Information Management System) is a database and transaction management system that was first introduced by IBM in 1968.

  • IBM Pureflex

    IBM PureFlex is a combined hardware and software system for data centers that delivers infrastructure as a system (IaaS) optimized for scalable cloud computing.

  • IBM Roadrunner

    Roadrunner was a supercomputer developed by IBM at the Los Alamos National Laboratory in New Mexico.

  • information technology (IT)

    Information technology (IT) is the use of computers, storage, networking and other physical devices, infrastructure and processes to create, process, store, secure and exchange all forms of electronic data.

  • ISAM (Indexed Sequential Access Method)

    ISAM (Indexed Sequential Access Method) is a file management system developed at IBM that enables records to be accessed either sequentially, in the order they were entered or randomly with an index.

  • ISO (International Organization for Standardization)

    ISO (International Organization for Standardization) is a worldwide federation of national standards bodies.

  • ISO 9000

    ISO 9000 is a series of standards, developed and published by the International Organization for Standardization (ISO).

  • What is infrastructure (IT infrastructure)?

    Infrastructure is the foundation or framework that supports a system or organization.

  • What is ISO 50001 (International Organization for Standardization 50001)?

    ISO 50001 (International Organization for Standardization 50001) is a voluntary standard for designing, implementing and maintaining an energy management system.

  • What is ITIL? A guide to the IT Infrastructure Library

    ITIL (Information Technology Infrastructure Library) is a framework designed to standardize the selection, planning, delivery, maintenance and overall lifecycle of IT services within a business.

  • J

    job

    In certain computer operating systems, a job is the unit of work that a computer operator -- or a program called a job scheduler -- gives to the OS.

  • job scheduler

    A job scheduler is a computer program that enables an enterprise to schedule and, in some cases, monitor computer 'batch' jobs (units of work).

  • What is JCL (job control language)?

    JCL (job control language) is a language for describing jobs to the Multiple Virtual Storage (MVS), OS/390 and Virtual Storage Extended (VSE) operating systems (OSes), which run on IBM's S/390 mainframe computers.

  • K

    kernel panic

    A kernel panic refers to a computer error from which the system's operating system (OS) cannot quickly or easily recover.

  • What is a kernel?

    A kernel is the essential foundation of a computer's operating system (OS). It's the core that provides basic services for all other parts of the OS.

  • L

    LEED (Leadership in Energy and Environmental Design)

    Leadership in Energy and Environmental Design, more commonly known as LEED, is an environmentally oriented building certification program run by the U.S. Green Building Council (USGBC).

  • lights-out management (LOM)

    Lights-out management (LOM) is a form of out-of-band management.

  • Linux distros (Linux distribution)

    A Linux distribution -- often shortened to "Linux distro" -- is a version of the open source Linux operating system that is packaged with other components, such as an installation programs, management tools and additional software such as the KVM hypervisor.

  • Linux operating system

    Linux is a Unix-like, open source and community-developed operating system (OS) for computers, servers, mainframes, mobile devices and embedded devices.

  • Linux swappiness

    Linux swappiness is a kernel parameter that determines how aggressively the Linux virtual machine (VM) swaps pages between memory and the swap space on the system's disk.

  • load shedding

    Load shedding (loadshedding) is a way to distribute demand for electrical power across multiple power sources.

  • logical volume management (LVM)

    Logical volume management (LVM) is a form of storage virtualization that offers system administrators a more flexible approach to managing disk storage space than traditional partitioning.

  • M

    mainframe (big iron)

    A mainframe (also known as 'big iron') is a high-performance computer used for large-scale computing purposes that require greater availability and security than a smaller-scale machine can offer... (Continued)

  • mechanical refrigeration

    Mechanical refrigeration, often referred to simply as refrigeration or air conditioning, is a process by which heat is removed from a location using a human-made heat exchange system.