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.

  • #

    64-bit processor

    A 64-bit processor is a microprocessor with a word size of 64 bits, a requirement for memory and data intensive applications such as computer-aided design (CAD) applications, database management systems, technical and scientific applications, and high-performance servers.

  • A

    abend (abnormal end)

    An abend (a combining of two words, abnormal end, when operator messages were as short as possible) is an abnormal, rather than planned, end or termination of a computer program because of some problem with how it is running.

  • access layer

    The access layer is where host computers and end users connect to the network.

  • ACF2 or CA-ACF2 (Access Control Facility)

    ACF2 (more formally, CA-ACF2; the ACF stands for Access Control Facility) is a set of programs from Computer Associates that enable security on mainframes.

  • alien crosstalk (AXT)

    Alien crosstalk (AXT) is electromagnetic noise that can occur in a cable that runs alongside one or more other signal-carrying cables.

  • ambient temperature

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

  • ANSI (American National Standards Institute)

    ANSI, American National Standards Institute, organization for fostering, development of technology standards, industry groups, International Organization for Standardization, ISO, International Electrotechnical Commission, IEC, computer standards, American Standard Code, Information Interchange, ASCI, Small Computer System Interface, SCSI, what is, definition, term, glossary

  • ARM server

    An advanced RISC machine (ARM) server is an enterprise-class computer server that employs a large array of ARM processors rather than a complement of x86-class processors.

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

    ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) is an organization devoted to the advancement of indoor-environment-control technology in the heating, ventilation and air conditioning (HVAC) industry

  • assembler

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

  • automatic transfer switch (ATS)

    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

    back-end

    Front-end and back-end are terms used to characterize program interfaces and services relative to the initial user of these interfaces and services.

  • baffle (data center hot aisle containment)

    Baffle paneling covers unwanted space between racks, under the raised floor and above dropped ceilings in the data center, reducing energy consumption and power use.

  • bash (Bourne Again Shell)

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

  • 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.

  • batch

    In a computer, a batch job is a program that is assigned to the computer to run without further user interaction.

  • 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.

  • Bloom Energy Server (Bloom box)

    A Bloom Box, officially known as an Bloom Energy Server, is a modular stack of solid oxide fuel cells that can produce electricity.

  • bogomips

    Bogomips is a measurement provided in the Linux operating system that indicates in a relative way how fast the computer processor runs.

  • boot loader (boot manager)

    A boot loader, also called a 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 at AT&T. Named for its developer, Stephen Bourne, the Bourne shell is also known by its program name, "sh". The shell prompt (character displayed to indicate readiness for input) used is the "$" symbol. The Bourne shell family includes the Bourne, Korn shell, bash, and zsh shells.

  • 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.

  • BSD (Berkeley Software Distribution)

    BSD (originally: Berkeley Software Distribution) refers to the particular version of the UNIX operating system that was developed at and distributed from the University of California at Berkeley.

  • building management system

    Building management system (BMS) is a computer system that tracks power used by IT equipment and air conditioning systems in the data center.

  • C

    CADE (Corporate Average Data center Efficiency)

    CADE (Corporate Average Data center Efficiency) is a metric used to rate the overall energy efficiency of an organization's data centers. CADE was introduced in a joint Uptime Institute and McKinsey report that proposed the metric as a single key performance indicator that could be used to compare the energy consumption of one data center against another. CADE combines measurements of the energy efficiency and utilization of IT equipment and facilities into a single percentage. (Continued...)

  • 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.

  • carbon usage effectiveness (CUE)

    Carbon usage effectiveness (CUE) is a metric developed by The Green Grid to help organizations measure the amount of carbon used -- or carbon footprint -- in the daily operations of their data centers.

  • Categories of twisted pair cabling systems

    ANSI/EIA (American National Standards Institute/Electronic Industries Association) Standard 568 is one of several standards that specify "categories" (the singular is commonly referred to as "CAT") of twisted pair cabling systems, such as wires, junctions, and connectors.

  • CEEDA (Certified Energy-Efficient Datacenter Award)

    CEEDA is a data center certification for the efficient use of energy.

  • channel

    In telecommunications in general, a channel is a separate path through which signals can flow. Depending on the context, this term has various meanings.

  • CICS (Customer Information Control System)

    CICS (Customer Information Control System) is an online transaction processing (OLTP) program from IBM that, together with the COBOL programming language, has formed over the past several decades the most common set of tools for building customer transaction applications in the world of large enterprise mainframe computing.

  • Cisco Catalyst Blade Switch 3020

    The Cisco Catalyst Blade Switch 3020 is a switch designed for the Hewlett-Packard (HP) BladeSystem c-Class of blade servers... (Continued)

  • CMDB (configuration management database)

    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 (information technology) services and the relationships between those components.

  • colocation (colo)

    A colocation facility, or colo, is a data center facility in which a business can rent space for servers and other computing hardware.

  • colocation marketplace

    A colocation marketplace is an online platform that connects colocation users with managed service providers, IT vendors and potential business partners.

  • compaction

    In a data center, compaction is the reduction or consolidation of hardware to make better use of physical floor space.

  • computer room air conditioning unit (CRAC)

    A computer room air conditioning (CRAC) unit is a device that monitors and maintains the temperature, air distribution and humidity in a network room or data center. CRAC units are replacing air-conditioning units that were used in the past to cool data centers. According to Industrial Market Trends, mainframes and racks of servers can get as hot as a seven-foot tower of powered toaster ovens, so climate control is an important part of the data center's infrastructure.

  • 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.

  • computerized maintenance management system (CMMS)

    A computerized maintenance management system (CMMS) is software that helps operations and maintenance staff identify and track the status of maintenance tasks and availability of replacement parts.

  • converged data center

    A converged data center pre-integrates server, storage and networking hardware with management, hypervisor and operating system platforms, as well as applications and services.

  • COTS, MOTS, GOTS, and NOTS

    COTS, MOTS, GOTS, and NOTS are abbreviations that describe pre-packaged software or hardware purchase alternatives.

  • cow power (biogas)

    Cow power is a term for the conversion of manure to usable energy. The energy produced can supplement the electric power offered by a utility or power a facility, such as a factory or a data center.

  • CRON script

    A CRON script is a list of one or more commands to a computer operating system or application server that are to be executed at a specified time.

  • 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 at a specified time.

  • Cygwin

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

  • D

    data center

    A data center (or datacenter) is a facility composed of networked computers and storage that businesses and other organizations use to organize, process, store and disseminate large amounts of data.

  • data center administrator (DCA)

    A data center administrator monitors systems, installs equipment and cabling, and participates in change processes and everyday procedures that support information technology.

  • data center as a service (DCaaS)

    A data center as a service (DCaaS) provider will supply turnkey physical data center facilities and computing infrastructure (e.g., servers, networking, storage, and so on) to clients in the form of a service.

  • 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 evaporative cooling (swamp cooling)

    Evaporative cooling, also known as swamp cooling, is a strategy for cooling air that takes advantage of the drop in temperature that occurs when water that's exposed to moving air begins to change to gas. You've probably experienced the effects of evaporative cooling if you've ever changed out of wet clothes because you felt chilled.

  • 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 resiliency

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

  • data center services

    Data center services is a collective term for all the supporting components necessary to the proper operation of data center. This includes all the implementation, maintenance and 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. Integrity involves maintaining the consistency, accuracy and trustworthiness of data over its entire life cycle.

  • Debian

    Debian is a popular and freely-available computer operating system that uses the Linux kernel and other program components obtained from the GNU project.

  • distribution

    In marketing, distribution is the process of moving a product from its manufacturing source to its customers. In computer software, distribution is the phase that follows packaging.

  • 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 the use of a metal or plastic pipe to carry air from one place to another.

  • E

    e-cycling

    E-cycling is the practice of reusing, or distributing for reuse, electronic equipment and components rather than discarding them at the end of their life cycle.

  • e-waste

    E-waste is any refuse created by discarded electronic devices and components as well as substances involved in their manufacture or use.

  • economizer

    An economizer is a mechanical device used to reduce energy consumption. Economizers recycle energy produced within a system or leverage environmental temperature differences to achieve efficiency improvements. (Continued...)

  • edge data center

    Edge data centers are small data centers that are 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)

    Following specific standards, EDI is a way for businesses to securely transfer important data, such as invoices and purchase orders, via the Internet.

  • Emergency Power Off (EPO) button

    The Emergency Power Off (EPO) button -- sometimes called an EPO switch -- is a large red device in data centers that kills power to a particular piece of equipment, or to an entire 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. (Continued...)

  • 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)

    The Evaluation Assurance Level (EAL) is a grade assigned to an IT product or system after completing a Common Criteria security evaluation.

  • event forwarding

    Event forwarding is the transmission of information to a centralized computer concerning events that take place on remote computers or servers... (Continued)

  • 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 is a popular open source Linux-based operating system.

  • field-replaceable unit (FRU)

    In computer systems, a field-replaceable unit (FRU) is a circuit board or part that can be removed and replaced without having to send the entire 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.

  • fuel cell

    A fuel cell is an electrochemical cell that derives its energy from combustible substances such as hydrogen, methane, propane, methanol, diesel fuel or even gasoline... (Continued)

  • G

    GNOME (GNU Network Object Model Environment)

    GNOME (GNU Network Object Model Environment, pronounced gah-NOHM) is a graphical user interface (GUI) and set of computer desktop applications for users of the Linux operating system.

  • GNU General Public License (GNU GPL or simply GPL)

    The GNU General Public License, often shortened to GNU GPL (or simply GPL), lists terms and conditions for copying, modifying and distributing free software.

  • GNU Linux

    The GNU Linux project was created for the development of a Unix-like operating system that comes with source code that can be copied, modified, and redistributed... (Continued)

  • green computing

    Green computing is the use of computers and related resources in an environmentally responsible manner. This involves the implementation of energy-efficient central processing units (CPUs), servers and peripherals as well as proper disposal of electronic waste (e-waste)... (Continued)

  • green data center

    A green data center is a repository for the storage, management, and dissemination of data in which the mechanical, lighting, electrical and computer systems are designed for maximum energy efficiency and minimum environmental impact... (Continued)

  • grid computing

    Grid computing uses small, distributed resources from servers and PCs to solve big problems. But will this architecture survive the cloud era?

  • 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)

  • H

    hardware clustering

    Hardware clustering is a hardware-based method of turning multiple servers into a cluster (a group of servers that acts like a single system).

  • Heartbeat

    Heartbeat is a program that runs specialized scripts automatically whenever a system is initialized or rebooted. Originally designed for two-node Linux-based clusters, Heartbeat is extensible to larger configurations... (Continued)

  • high availability (HA)

    High availability (HA) is the ability of a system to operate continuously without failing for a designated period of time.

  • high-performance computing (HPC)

    High-performance computing (HPC) is the use of parallel processing for running advanced application programs efficiently, reliably and quickly. The term applies especially to systems that function above a teraflop or 1012 floating-point operations per second... (Continued)

  • Hot spot/cold spot

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

  • hot/cold aisle

    Hot aisle/cold aisle is a layout design for server racks and other computing equipment in a data center. The goal of a hot aisle/cold aisle configuration is to conserve energy and lower cooling costs by managing air flow.

  • HVAC (heating, ventilation, and air conditioning)

    HVAC stands for heating, ventilation, and air conditioning.

  • hydrofluorocarbon (HFC) clean agent

    Data centers and telecom rooms use hydrofluorocarbon (HFC) clean agent systems for fire protection to avoid damaging electrical and electronic equipment.

  • I

    IBM Integrated Facility for Linux (IFL)

    The Integrated Facility for Linux (IFL) is a specialty engine processor on IBM System z mainframe servers that is dedicated to Linux workloads. Operational efforts, software costs, energy use and hardware footprint are reduced when Linux is deployed on IFL rather than general-purpose processors.

  • IBM Roadrunner

    Roadrunner is the fastest supercomputer in the world, twice as fast as Blue Gene and six times as fast as any of the other current supercomputers. IBM developed Roadrunner for the Los Alamos National Laboratory in New Mexico. (Continued...)

  • IBM System z Application Assist Processor (zAAP)

    The IBM System z Application Assist Processor (zAAP) is a specialty engine that provides a performance environment for Web-based apps and service-oriented architecture-based technologies, e.g. XML and Java.

  • IBM System z Integrated Information Processor (zIIP)

    IBM's System z Integrated Information Processor (zIIP) is a specialty offload engine that helps improve computing performance for a subset of mainframe workloads.

  • IMS (Information Management System)

    IMS (Information Management System) is a database and transaction management system that was first introduced by IBM in 1968. Since then, IMS has gone through many changes in adapting to new programming tools and environments.

  • information technology (IT)

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

  • infrastructure (IT infrastructure)

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

  • intelligent power management (IPM)

    Intelligent Power Management (IPM) is a combination of hardware and software that optimizes the distribution and use of electrical power in computer systems and data centers. While the installation of IPM involves up-front cost and ongoing maintenance, the technology can save money in the long term as a result of reduced electric bills, reduced downtime and prolonged hardware life... (Continued)

  • ISAM (Indexed Sequential Access Method)

    ISAM (Indexed Sequential Access Method) is a file management system that allows records to be accessed either sequentially or randomly.

  • ISO (International Organization for Standardization)

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

  • ISO 50001 (International Organization for Standardization 50001)

    ISO 50001 is a standard for designing, implementing and maintaining an energy management system.

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