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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  • H

    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.

  • hyper-converged appliance

    A hyper-converged appliance is a hardware device that provides multiple data center management technologies within a single box.

  • hyper-converged network

    A hyper-converged network is a network that combines compute and storage network resources into a single preconfigured stack, server or brick with heavy use of virtualization. Typically, a hyper-converged network is built on server hardware that uses virtualized storage, unifying all hard disks or SSD’s into a single storage stack.

  • hyper-converged storage

    Hyper-converged storage is a software-defined approach to storage management that combines storage, compute, virtualization and sometimes networking technologies in one physical unit that is managed as a single system.

  • 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 hyper-converged infrastructure? Guide to HCI

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

  • 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 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 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 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...)

  • indemnification

    In service level agreements (SLAs) and other legal contracts such as end-user license agreements (EULAs), indemnification is the part of an agreement that provides for one party to bear the monetary costs, either directly or by reimbursement, for losses incurred by a second party.

  • 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.

  • integrated stack

    An integrated stack is a vendor product that provides an enterprise information technology (IT) customer with a scalable network, storage and server infrastructure that comes pre-loaded with virtualization, automation and management software.

  • 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.

  • ISO 9000

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

  • ITIL (Information Technology 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

    JCL (job control language)

    JCL (job control language) is a language for describing jobs (units of work) to the MVS, OS/390, and VSE operating systems, which run on IBM's S/390 large server (mainframe) computers.

  • job

    In certain computer operating systems, a job is the unit of work that a computer operator gives to the operating system.

  • job scheduler

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

  • job step

    In certain computer operating systems, a job step is part of a job, a unit of work that a computer operator (or a program called a job scheduler) gives to the operating system.

  • K

    kernel

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

  • kernel panic

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

  • Kyoto cooling (Kyoto wheel)

    KyotoCooling is an energy-efficient free cooling system for data centers. Kyoto cooling uses outside air to remove the heat created by computing equipment instead of using mechanical refrigeration.

  • L

    LEED (Leadership in Energy and Environmental Design)

    LEED (Leadership in Energy and Environmental Design) is an ecology-oriented building certification program run under the auspices of the U.S. Green Building Council (USGBC)... (Continued)

  • 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 kernel panic

    Linux kernel panic occurs when the operating system discovers a potentially fatal error that affects the Linux kernel.

  • 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 stream

    A Linux stream is information traveling in a Linux shell from one process to another via a pipe, or from one file to another via a redirect.

  • Linux swappiness

    Linux swappiness is the rate at which a Linux platform's kernel moves pages into and out of active memory.

  • load bank

    A load bank is a device that generates a prescribed amount of electricity draw to test the reliability of electrical switching, generator output, uninterruptable power supply (UPS) systems and cooling in a data center.

  • load shedding

    Load shedding is a reduction of power demand by a utility provider during peak or stressed times. Participants voluntarily reduce demand for utility power and rely on secondary sources for uninterrupted operation, or lower or lose power supply in an involuntary load shedding event.

  • logical volume management (LVM)

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

  • Lustre

    Lustre is an open source parallel distributed file system (DFS) specialized for large-scale cluster computing. The name is a portmanteau of Linux and cluster.

  • 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)

  • Management and Operations (M&O) Stamp of Approval

    The Management and Operations (M&O) Stamp of Approval from the Uptime Institute is a certification of the critical facilities and management operations procedures of a data center.

  • Mathematical symbols

    This table contains mathematical symbols and links to definitions of what they represent and how they are used.

  • 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.

  • motherboard tattoo

    A motherboard tattoo is a colloquial term once used to denote an ID code that is written in the basic input/output system (BIOS) of a computer to uniquely identify the computer.

  • moves, adds and changes (MAC)

    Moves, adds and changes (MAC) keep computing equipment in line with user needs and up-to-date, with disciplined process management.

  • 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 coordinated processing of programs by more than one computer processor.

  • MVS (Multiple Virtual Storage)

    MVS (Multiple Virtual Storage) is IBM's best-known operating system for mainframe and large servers. Released in 1974, MVS successor systems include OS/390 and z/OS.

  • N

    National Electrical Code (NEC)

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

  • network convergence

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

  • Nutanix

    Nutanix is a hyper-converged infrastructure pioneer that markets its technology as a building block for private clouds.

  • Nutanix Acropolis

    Acropolis is a free server virtualization hypervisor developed by vendor Nutanix that is packaged on hyper-converged appliances, and can be used alongside competing hypervisors.

  • Nutanix Prism

    Users manage Nutanix hyper-converged infrastructure technology through Prism -- software that provides management of clusters, virtual machines and networking through a single interface.

  • O

    OLTP (online transaction processing)

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

  • one throat to choke

    One throat to choke is an expression used in business to describe the advantage of purchasing goods or integrated services from a single vendor.

  • Open Compute Project

    The Open Compute Project is an initiative started by Facebook to share efficient server and data center designs with the general IT industry.

  • out-of-order execution (OoOE)

    Out-of-order execution (OoOE) is an approach to processing that allows instructions for high-performance microprocessors to begin execution as soon as their operands are ready.

  • P

    parallel processing

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

  • Paris Agreement

    The Paris Agreement is an international treaty that seeks to reduce the emission of greenhouse gases. The agreement is sponsored by the United Nations Framework Convention on Climate Change (UNFCCC) and seeks to limit temperature increases in the 21st century to below 2 degrees Celsius.

  • Peripheral Component Interconnect Express (PCIe, PCI-E)

    PCIe is a high-speed serial interconnection standard for connecting peripheral devices to a computer's motherboard.

  • 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.

  • plenum

    In buildings, a plenum is a separate space provided for air circulation for heating, ventilation, and air-conditioning (sometimes referred to as HVAC) and typically provided in the space between the structural ceiling and a drop-down ceiling.

  • power cycling

    Power cycling is the process of turning hardware off and then turning it on again. In the data center, technicians use power cycling to test the durability and reliability of network components.

  • power distribution unit (PDU)

    A power distribution unit (PDU) is a device for controlling electrical power in a data center.

  • power usage effectiveness (PUE)

    Power usage effectiveness (PUE) is a metric used to determine the energy efficiency of a data center.

  • private cloud appliance

    A private cloud appliance is a hardware device that provides software-defined converged infrastructure functions for an organization’s proprietary network.

  • R

    raceway

    A raceway is an enclosed conduit that forms a physical pathway for electrical wiring and protect wires and cables from heat, corrosion, water intrusion and other environmental threats.

  • 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.

  • 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.

  • 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.

  • Red Hat Satellite

    Red Hat Satellite is an IT infrastructure management tool primarily used to monitor and manage Red Hat Enterprise Linux environments.

  • remote hands

    Remote hands is the general name for a service offered by colocation providers that enables customers to delegate IT management and maintenance tasks in a colocation facility to technicians hired by the provider.

  • Restriction of Hazardous Substances Directive (RoHS Directive)

    The Restriction of Hazardous Substances (RoHS) Directive is a set of criteria formulated by the European Union (EU) to regulate the use of toxic materials in electrical and electronic devices, systems, and toys... (Continued)

  • RPM Package Manager (Red-hat Package Manager)

    RPM Package Manager (RPM), originally called the Red-hat Package Manager, is a program for installing, uninstalling, and managing software packages in Linux.

  • rsync

    Rsync is a free software utility for Unix- and Linux-like systems that copies files and directories from one host to another. Rsync is available on most Linux distributions by default.

  • runlevel

    A runlevel is a Linux operating state that determines which programs can execute when the operating system restarts.

  • S

    scalability

    Scalability is the ability of a computer application or product (hardware or software) to continue to perform well when it (or its context) is changed in size or volume in order to meet a users need.

  • ScaleIO

    ScaleIO is a software-defined storage software product from Dell EMC that uses existing hardware or EMC servers to turn direct-attached storage (DAS) into shared block storage.

  • screen scraping

    Screen scraping is the act of copying information that shows on a digital display so it can be used for another purpose.

  • SDDC (software-defined data center)

    An SDDC (software-defined data center) is a data storage facility in which networking, storage, CPU and security are virtualized and delivered as a service.

  • SELinux (Security-Enhanced Linux)

    SELinux, or Security-Enhanced Linux, is a part of the Linux security kernel that acts as a protective agent on servers.

  • server consolidation

    Server consolidation is an approach to the efficient usage of computer server resources in order to reduce the total number of servers or server locations that an organization requires.

  • shell

    Shell is a UNIX term for the interactive user interface with an operating system.

  • shell script

    A shell script is a text file that contains a sequence of commands for a UNIX-based operating system.

  • SimpliVity

    SimpliVity Corp. is the Westborough, Massachusetts vendor of the hyper-converged storage product OmniCube.

  • single pane of glass

    A single pane of glass is a management console that presents data from multiple sources in a unified display. The glass, in this case, is a computer monitor or mobile device screen.

  • single point of failure (SPOF)

    A single point of failure (SPOF) is a potential risk posed by a flaw in the design, implementation or configuration of a circuit or system.

  • SMP (symmetric multiprocessing)

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

  • software-defined everything (SDE)

    Software-defined everything (SDE) is an umbrella term that describes how virtualization and abstracting workloads from the underlying hardware can be used to make information technology (IT) infrastructures more flexible and agile.

  • 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.

  • Supermicro

    Supermicro is a company that specializes in x86-64 server technology. The company targets consumer and enterprise markets and maintains a focus on power efficiency and green technology.

  • supervisor call (SVC)

    In computers, especially IBM mainframes, a supervisor call (SVC) 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.

  • SUSE Manager

    SUSE Manager is an open source infrastructure management tool for Linux systems.

  • sysplex and Parallel Sysplex

    A sysplex is IBM's systems complex (the word sysplex comes from the first part of the word system and the last part of the word complex), introduced in 1990 as a platform for the MVS/ESA operating system for IBM mainframe servers.

  • 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.

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