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.

Search Definitions
  • A

    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

    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

    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 a 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 services and the relationships among those components.

  • 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

    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.

  • E

    Electric plugs for each country

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

  • F

    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.

  • 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, 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.

  • 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 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.

  • 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.

  • ISO (International Organization for Standardization)

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

  • 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 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.

  • 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 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.

  • What is Linux distros (Linux distribution)?

    A Linux distribution -- often shortened to 'Linux distro' -- is a complete operating system based on Linux.

  • 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.

  • moves, adds and changes (MAC)

    Moves, adds and changes (MAC) refers to a set of tasks that IT teams regularly perform to keep computing equipment up to date and aligned with user and business requirements.

  • multicore processor

    A multicore processor is an integrated circuit that has two or more processors attached for enhanced performance and reduced power consumption. These processors also enable more efficient simultaneous processing of multiple tasks, such as with parallel processing and multithreading.

  • multiprocessing

    Multiprocessing is the utilization of two or more central processing units (CPUs) in a single computer system.

  • What is MVS (Multiple Virtual Storage)?

    MVS (Multiple Virtual Storage) is an OS from IBM that continues to run on many of IBM's mainframe and large servers.

  • N

    network convergence

    Network convergence is the efficient coexistence of telephone, video and data communication within a single network.

  • Nutanix

    Nutanix is a private and hybrid cloud software provider. It started as a hyperconverged infrastructure pioneer that now markets its technology as a building block for private clouds.

  • What is National Electrical Code (NEC)?

    National Electrical Code (NEC) is a set of regularly updated standards for the safe installation of electric wiring in the Americas.

  • O

    OLTP (online transaction processing)

    OLTP (online transaction processing) is a class of software programs capable of supporting transaction-oriented applications.

  • P

    Peripheral Component Interconnect Express (PCIe, PCI-E)

    Peripheral Component Interconnect Express (PCIe or PCI-E) is a serial expansion bus standard for connecting a computer to one or more peripheral devices.

  • pizza box server

    The term 'pizza box server' refers to the shape of a computer server enclosed in a rectangular and horizontally- arranged chassis and often installed in a rack with similar servers.

  • What is parallel processing?

    Parallel processing is a method in computing of running two or more processors, or CPUs, to handle separate parts of an overall task.

  • R

    raceway

    A raceway, sometimes referred to as a raceway system, is an enclosed conduit that forms a physical pathway for electrical wiring.

  • RAIN (redundant/reliable array of inexpensive/independent nodes)

    A reliable array of independent nodes (RAIN) is a heterogeneous cluster of compute and storage nodes connected in a fault-tolerant network topology that incorporates multiple interfaces and redundant hardware.

  • raised floor

    A raised floor is a data center construction model in which a slightly higher floor is constructed above the building's original concrete slab floor, leaving the open space created between the two for wiring or cooling infrastructure.

  • Red Hat

    Red Hat is a software company that combines open source Linux operating system components with related programs into a distribution package that customers can order.

  • Red Hat Enterprise Linux (RHEL)

    Red Hat Enterprise Linux (RHEL) is an enterprise Linux operating system (OS) developed by Red Hat for the business market.

  • runlevel

    A runlevel is an operating state on a Unix and Unix-based operating system that is preset on the Linux-based system.

  • What is a real-time operating system (RTOS)?

    A real-time operating system (RTOS) is an OS that guarantees real-time applications a certain capability within a specified deadline.

  • What is RPM Package Manager?

    RPM Package Manager (RPM), originally called the Red Hat Package Manager, is an open source program for installing, uninstalling and managing software packages in Linux.

  • S

    PowerFlex (formerly ScaleIO)

    PowerFlex is a software-defined storage product from Dell EMC. It is available as software only or as a prebuilt Dell server or rack appliance.

  • scalability

    In information technology, scalability (frequently spelled 'scaleability') has two uses: for a computer application to function with change in size and volume, and to take advantage of a rescale.

  • screen scraping

    Screen scraping is a data collection method used to gather information shown on a display to use for another purpose.

  • SELinux (Security-Enhanced Linux)

    SELinux, or Security-Enhanced Linux, is a part of the Linux kernel that acts as a protective agent to the operating system.

  • shell program

    A shell program is software that provides users with an interface for accessing services in the kernel.

  • SMP (symmetric multiprocessing)

    SMP (symmetric multiprocessing) is the processing of programs by multiple processors that share a common operating system and memory.

  • Spine-leaf (spine-leaf architecture)

    Spine-leaf, or leaf-spine, is a two-layer network topology composed of spine and leaf switches.

  • statistical mean, median, mode and range

    The terms mean, median, mode, and range describe properties of statistical distributions.

  • supervisor call (SVC)

    In computers, especially IBM mainframes, a supervisor call (SVC) instruction is a processor instruction that directs the processor to pass control of the computer to the operating system's supervisor program.

  • SUSE

    SUSE (pronounced soo-sah) is a multinational company that offers enterprise-grade open source products based on Linux technologies.

  • SUSE Linux Enterprise Server (SLES)

    SUSE Linux Enterprise Server (SLES) is a Linux-based server operating system created and maintained by the German-based organization, SUSE.

  • What is a shell script and how does it work?

    A shell script is a text file that contains a sequence of commands for a Unix-based operating system (OS).

  • What is a software-defined data center (SDDC)?

    A software-defined data center (SDDC) is a server management concept in which all infrastructure elements -- networking, storage and compute -- are virtualized and delivered as a service.

  • What is server sprawl and how to prevent it?

    Server sprawl is when multiple underutilized servers take up more space and consume more resources than can be justified by their workload.

  • T

    twisted pair

    Twisted pair is the ordinary copper wire that connects home and business computers to a telephone company.

  • What is total cost of ownership (TCO)?

    Total cost of ownership (TCO) is an estimation of the expenses associated with purchasing, deploying, managing, using and retiring IT assets, such as a product or piece of equipment.

  • U

    Ubuntu

    Ubuntu (pronounced oo-BOON-too) is a free, open source operating system (OS) based on Debian Linux.

  • unified computing system (UCS)

    A unified computing system (UCS) is a converged data center architecture that integrates computing, networking and storage resources to increase efficiency and enable centralized management.

  • Unix

    Unix -- trademarked as UNIX -- is a multiuser, multitasking operating system (OS) designed for flexibility and adaptability.

  • V

    vendor lock-in

    Vendor lock-in is a situation in which a customer using a product or service cannot easily transition to a competitor's product or service.

  • VSPEX

    VSPEX is a platform specification from Dell EMC to guide the building of systems for converged and hyper-converged infrastructure (HCI).

  • What is VSAM (Virtual Storage Access Method)?

    Virtual Storage Access Method (VSAM) is an access method for IBM's mainframe operating system, MVS, now called z/OS.

  • W

    Waste Electrical and Electronic Equipment (WEEE) Directive

    The Waste Electrical and Electronic Equipment (WEEE) Directive is a legislative act that the European Union adopted to address the growing amounts of e-waste that come from electrical and electronic equipment (EEE) at the end of its life.

  • white box server

    A white box server is a data center computer that is not manufactured by a well-known name-brand vendor.