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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  • L

    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.

  • 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.

  • 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.

  • 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

    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.

  • plenum

    In building construction, a plenum (pronounced PLEH-nuhm, from Latin meaning full) is a separate space provided for air circulation for heating, ventilation and air conditioning (sometimes referred to as HVAC).

  • power cycling

    Power cycling is the process of turning hardware off and then turning it on again.

  • 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.

  • 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.

  • 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.

  • 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.

  • single pane of glass

    A single pane of glass is a management console that presents data from multiple sources in a unified display.

  • 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.

  • 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

    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.

  • twisted pair

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

  • 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.

  • 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.

  • What is an 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.

  • 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.

  • 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 name-brand vendor.

  • workload

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

  • 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.