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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  • 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).

  • 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.

  • 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), 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)

  • 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) 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.

  • 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.

  • 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.

  • 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 colocation providers offer that enables customers to delegate IT management and maintenance tasks in a colocation facility to technicians hired by the provider.

  • 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.

  • runlevel

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

  • 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 a data collection method used to gather information shown on a display to use 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.

  • shell program

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

  • shell script

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

  • 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.

  • 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

    TCO (total cost of ownership)

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

  • technological convergence

    Technological convergence is a term that describes bringing previously unrelated technologies together, often in a single device.

  • The Green Grid Performance Indicator (PI)

    The Green Grid Performance Indicator (PI) is a set of metrics designed to help information technology (IT) teams assess current and future data center cooling performance. PI was developed by The Green Grid in 2016.

  • the Open19 project

    The Open19 project is aimed at standardizing servers, storage and networking components into a common set of form factors for any Electronic Industries Association (EIA) 19-inch data center rack. The initiative was launched by LinkedIn Corp. in 2016.

  • total benefit of ownership (TBO)

    Total benefit of ownership is the sum of measurable and intangible returns that a company receives from investing in assets and/or personnel.

  • twin server (0.5 U server)

    A twin server has two compute nodes housed side-by-side in 1U of data center rack space. Because each server node fills half of 1U, a twin server may also be referred to as a 0.5U server.

  • twisted pair

    Twisted pair is the ordinary copper wire that connects home and many business computers to the telephone company. (Continued...)

  • U

    U (measurement)

    A U is a standard unit of measure for designating the height in computer enclosures and server rack cabinets.

  • 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.

  • uninterruptible power supply (UPS)

    An uninterruptible power supply (UPS) is a device that allows a computer to keep running for at least a short time when incoming power is interrupted.

  • Unisys

    Unisys is an American multinational information technology company that provides hardware, software, IT services and consulting.

  • Unix

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

  • Uptime Institute's data center tier standards

    Data center tiers are a system created by Uptime Institute LLC to describe the availability of infrastructure resources in a facility.

  • utility computing

    Utility computing is a service provisioning model where a provider makes computing resources, infrastructure management and technical services available to customers as they need them.

  • 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.

  • VSAM (Virtual Storage Access Method)

    VSAM (Virtual Storage Access Method) is a file management system for IBM's larger operating systems now called z/OS.

  • VSPEX

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

  • 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.

  • water cooling

    Water cooling, also called liquid cooling, is a method used to lower the temperature of computer processor units (CPUs), and sometimes graphics processor units (GPUs).

  • wetware

    Wetware refers to programmers, developers, systems administrators, cloud and IT architects and other employees that directly affect how servers, applications, networks and the rest of an IT system functions.

  • white box server

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

  • wireless sensor network (WSN)

    A wireless sensor network is a group of specialized transducers with a communications infrastructure that uses radio to monitor and record physical or environmental conditions.

  • workload

    In computing, a workload, typically, is any program or application that runs on any computer.

  • Y

    Yellowdog Updater, Modified (YUM)

    Yellowdog Update, Modified (YUM) is a program that manages installation, updates and removal for Red Hat package manager (RPM) systems. YUM allows the user to update groups of machines without having to update each RPM separately.

  • Yet another Setup Tool (YaST)

    YaST handles much of the administration load, offers a simple graphical interface and sets up setting system parameters easily.

  • Z

    z/OS

    Introduced in 2000, IBM z/OS is a 64-bit mainframe operating system (OS) developed by IBM for its family of enterprise z/Architecture mainframe computers.

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