See air, cabinet
TGG Glossary
This is a glossary of older terms. While many of the definitions are unchanged, some of the definitions may be out of date and some of the terms may no longer be in use in the Data Center industry. This legacy glossary provides definitions for hundreds of information and communications technology (ICT) and data center terms and acronyms. Arranged alphabetically and searchable, the glossary explains common industry vocabulary.
Cabinet Air
Cache Battery
A component type of data center class server. Source: Intel
CAF
Conductive anodic failure
CAGR
Compound annual growth rate. Source: ASHRAE
Capacity
The maximum amount that something can contain. Source: Oxford Languages
Carcinogen
A substance or a mixture which induce cancer or increase its incidence. Source: United Nations GHS
CAT3
Category 3 balanced cable
CAT5
Category 5 balanced cable
CAV
Constant air volume
Central Office (CO)
A building within a telephone network that houses equipment for processing (receiving, transmitting, redirecting, etc.) voice signals and digital data, connecting a larger number of lower speed to a smaller number of higher speed lines
Central Processing Unit (CPU)
Also called a processor. In a computer, the CPU is the processor on an IC chip that serves as the heart of the computer, containing a control unit, the arithmetic and logic unit (ALU), and some form of memory. It interprets and carries out instructions, performs numeric computations, and controls the external memory and peripherals connected to it
Central Processing Unit (CPU)
A component type of data center class server. Source: Intel
CFC
Chlorofluorocarbons, an EPA targeted greenhouse gas. Source: United States Department of Energy
CFM
Cubic Feet per Minute. Source: Oxford Languages
CH4
Methane, an EPA targeted greenhouse gas. Source: United States Department of Energy
Chassis
The physical framework of the computer system that houses all electronic components, their interconnections, internal cooling hardware, and power supplies
Chemical stability
Chemical stability, when used in the technical sense, means thermodynamic stability of a chemical system. In corrosion, it is the ability to resist corrosion under specific environmental conditions. It is the tendency of a material to resist change or decomposition due to internal reaction, or due to the action of air, heat, light, pressure, etc. a parameter of evaluation for fluids used to cool data center equipment. Source: Corrosionpedia.com
Chief Executive Officer (CEO)
A chief executive officer, the highest-ranking person in a company or other institution, responsible for making managerial decisions. a stakeholder in the decision to invest, divest, use, source liquid cooled data center environments. Source: Oxford Languages
Chief Financial Officer (CFO)
A chief financial officer, a senior executive with responsibility for the financial affairs of a corporation or other institution. a stakeholder in the decision to invest, divest, use, source liquid cooled data center environments. Source: Oxford Languages
Chief Risk Officer (CRO)
A chief risk officer is a corporate executive responsible for identifying, analyzing, and mitigating internal and external risks. The chief risk officer works to ensure that the company complies with government regulations, such as Sarbanes-Oxley, and reviews factors that could hurt investments or a company's business units. a stakeholder in the decision to invest, divest, use, source liquid cooled data center environments. Source: Investopedia
Chief Technology Officer (CTO)
A chief technology (or technical) officer, a senior executive with responsibility for managing the technological requirements of a company or other institution. a stakeholder in the decision to invest, divest, use, source liquid cooled data center environments. Source: Oxford Languages
Chilled Water
A commodity often used to cool a building's air and equipment, especially in situations where many individual rooms must be controlled separately, such as a hotel. The chilled water can be supplied by a vendor, such as a public utility or created at the location of the building that will use it, which has been the norm. Source: Wikipedia
Chilled Water System
A type of air conditioning system that has no refrigerant in the unit itself. The refrigerant is contained in a chiller, which is located remotely. The chiller cools water, which is piped to the air conditioner to cool the space. An air or process conditioning system containing chiller(s), water pump(s), a water piping distribution system, chilled-water cooling coil(s), and associated controls. The refrigerant cycle is contained in a remotely located water chiller. The chiller cools the water, which is pumped through the piping system to the cooling coils.
Chiller
A machine for cooling something, especially a cold cabinet or refrigerator for keeping stored food a few degrees above freezing. Water-cooled and air-cooled chillers, modelled at 0.577 kW/ton and 1.2 kW/ton, respectively. Source: Oxford Languages
Chip
Identifies the actual microprocessor, the physical package, containing one or more cores
CIPM
Comité International des Poids et Mesures (CIPM) a.k.a. International Committee on Weights and Measures, manages the Metric system or SI. Source: BIPM
Circuit(s)
A complete and closed path around which a circulating electric current can flow. Source: Oxford
CITE
ASHRAE Compliance for IT Equipment. Source: ASHRAE
Classes of Fires
* Class A: Fires involving ordinary combustibles such as paper, wood, or cloth
* Class B: Fires involving burning liquids
* Class C: Fires involving any fuel and occurring in or on energized electrical equipment
* Class D: Fires involving combustible metals (such as magnesium)
Client
A server system that can operate independently, but has some interdependence with another server system
Climate Change
A change in global or regional climate patterns, in particular a change apparent from the mid to late 20th century onwards and attributed largely to the increased levels of atmospheric carbon dioxide produced by the use of fossil fuels. Source: Oxford Languages
Cloud Data Center
Data center which your organization owns/operates, running cloud infrastructure hosting workloads of other organizations. Source: Uptime Institute
Cluster
Two or more interconnected servers that can access a common storage pool. Clustering prevents the failure of a single file server from denying access to data and adds computing power to the network for large numbers of users
CMOS Electronic Technology
This technology draws considerably less power than bipolar semiconductor technology in standby mode, and so it replaced many of the digital bipolar applications around the early 1990s
CO2
Carbon dioxide, an EPA targeted greenhouse gas. Source: United States Department of Energy
Coefficient of Performance (COP) - Cooling
The ratio of the rate of heat removal to the rate of energy input in consistent units for a complete cooling system or factory-assembled equipment as tested under a nationally recognized standard or designated operating conditions
Cogeneration
The generation of electricity and other energy jointly, especially the utilization of the steam left over from electricity generation to produce heat. Source: Oxford Languages
Cold Aisle
See hot aisle/cold aisle
Cold Plate
Cold plates are typically aluminum or copper plates of metal that are mounted to electronic components. Cold plates can have various liquids circulating within their channels. Typically, a plate with cooling passages through which liquid flows to remove the heat from the electronic component to which it is attached
Cold Plate 2-Phase
A classification type of data center cooling. Source: NVIDIA
Cold Plate Single-Phase
A classification type of data center cooling. Source: NVIDIA
Cold Plates
Liquid Cold Plates are responsible for transferring heat from surfaces with high heat loads to the fluid used within a liquid cooling system. Source: BOYD
Colocation Data Center
Data center which your organization owns/operates, with space leased to tenants of other organizations. Source: Uptime Institute
Combustion turbine
A unit that is a rotary engine driven by a gas under pressure that is created by the combustion of any fuel. Source: United States Department of Energy
Commissioning
The process of ensuring that systems are designed, installed, functionally tested, and capable of being operated and maintained to perform in conformity with the design intent. It begins with planning and includes design, construction, start-up, acceptance, and training, and can be applied throughout the life of the building
Commissioning Levels
* Factory acceptance tests (Level 1 commissioning): Testing of products prior to leaving their place of manufacture
* Field component verification (Level 2 commissioning): Inspection and verification of products upon receipt
* System construction verification (Level 3 commissioning): Field inspections and certifications that components are assembled and properly integrated into systems as required by plans and specifications
* Site acceptance testing (Level 4 commissioning): Activities that demonstrate that related components, equipment, and ancillaries that make up a defined system operate and function to rated, specified, and/or advertised performance criteria
* Integrated systems tests (Level 5 commissioning): Testing of redundant and backup components, systems, and groups of interrelated systems to demonstrate that they respond as predicted to expected and unexpected anomalies
Commissioning Plan
A document that defines the verification and testing process to ensure the project delivers what is expected, including training, documentation, and project close-out
Communication Equipment
Equipment used for information transfer. The information can be in the form of digital data for data communications or analog signals for traditional wireline voice communication
* Core network or equipment: A core network is a central network into which other networks feed. Traditionally, the core network has been the circuit-oriented telephone system. More recently, alternative optical networks bypass the traditional core and implement packet-oriented technologies. Significant to core networks is "the edge," where networks and users exist. The edge may perform intelligent functions that are not performed inside the core network
* Edge equipment or devices: In general, edge devices provide access to faster, more efficient backbone and core networks. The trend is to make the edge smart and the core "dumb and fast." Edge devices may translate between one type of network protocol and another
Competent Authority
Any national body(ies) or authority(ies) designated or otherwise recognized as such in connection with the Globally Harmonized Systems of Classification and Labelling of Chemicals (GHS). Source: United Nations GHS
Compiler
A program that translates (presumably) human-readable source code into a form that is native for a particular machine
Computational Fluid Dynamics (CFD)
A computational technology that enables you to study the dynamics of fluid flow and heat transfer numerically
Compute Server
Servers dedicated for computation or processing that are typically required to have greater processing power (and, hence, dissipate more heat) than servers dedicated solely for storage (also see server)
Compute-intensive
Term that applies to any computer application that demands a lot of computation, such as meteorology programs and other scientific applications. A similar but distinct term, computer-intensive, refers to applications that require a lot of computers, such as grid computing. The two types of applications are not necessarily mutually exclusive. Some applications are both compute- and computer-intensive
Computer rack component
Various accessories or components for computer racks (including rack shelves, panels, doors, conversion kits, etc.) [ KEY=145100;UNSPSC=43201618;V23.07 || IDEA || ISO 22745-11 COMPLIANCE Source: eOTD ECCMA Open Technical Dictionary is an ISO 22745 compliant dictionary managed by ECCMA
Computer Room Air Conditioning (CRAC)
A modular packaged environmental control unit designed specifically to maintain the ambient air temperature and/or humidity of spaces that typically contain data communcations equipment. These products can typically perform all (or a subset) of the following functions: cool, reheat, humidify, dehumidify. They may have multiple steps for some of these functions. CRAC units should be specifically designed for data and communications equipment room applications and meet the requirements of ANSI/ASHRAE Standard 127-2001, Method of Testing for Rating Computer and Data Processing Room Unitary Air Conditioners
Computer System Availability
Probability that a computer system will be operable at a future time (takes into account the effects of failure and repair/maintenance of the system)
Computer System Reliability
Probability that a computer system will be operable throughout its mission duration (only takes into account the effects of failure of the system)
Computer Workstation
A high-end microcomputer designed for technical or scientific applications. It has sufficient RAM, storage capacity and processing speed to facilitate computation intensive design and technical analysis. They are optimized for the visualization and manipulation of different types of complex data such as 3D mechanical design, engineering simulation, animation and rendering of images, and mathematical plots. Consoles consist of a high-resolution display, a keyboard, and a mouse at a minimum, but also offer multiple displays, graphics tablets, 3D mice, etc. [ KEY=166799;UNSPSC=43211515;V23.07 || IDEA || ISO 22745- 11 COMPLIANCE Source: eOTD ECCMA Open Technical Dictionary is an ISO 22745 compliant dictionary managed by ECCMA
Condenser
Heat exchanger in which vapor is liquefied (state change) by the rejection of heat as a part of the refrigeration cycle
Conditioned Air
See air, conditioned
Conduit
A tube or trough for protecting electric wiring or channel for conveying water or other fluid. Source: Oxford Languages
Connector
A device for keeping two parts of an electric circuit in contact, a component of liquid cooling solutions. Source: Oxford Languages
Coolant
A liquid or gas that is used to remove heat from something. Source: Oxford Languages
Cooling
Removal of heat
Cooling Distribution Units (CDUs)
Cooling distribution units transfer heat from the rack to the chilled water loop. Source: ASHRAE
Cooling Tower
Cooling towers are specialized heat exchangers that remove heat from water mainly by means of latent heat loss from evaporation while coming into contact with an airstream. Aside from evaporative cooling, water is also cooled by sensible heat transfer due to the temperature difference between air and water. Cooling towers are basically heat exchangers, but instead of the usual conduction-convection of shell and tube or plate heat exchangers, it generates cooling by bringing water and air into contact. Source: iqsdirectory.com
Cooling Tower
Heat-transfer device, often tower-like, in which atmospheric air cools warm water, generally by direct contact (heat transfer and evaporation)
Cooling, Air
Conditioned air is supplied to the inlets of the rack/cabinet/server for convective cooling of the heat rejected by the components of the electronic equipment within the rack. It is understood that within the rack, the transport of heat from the actual source component (e.g., CPU) within the rack itself can be either liquid- or air-based, but the heat rejection media from the rack to the building cooling device outside the rack is air. The use of heat pipes or pumped loops inside a server or rack where the liquid remains is still considered air cooling
Cooling, Liquid
Conditioned liquid is supplied to the inlets of the rack/cabinet/server for thermal cooling of the heat rejected by the components of the electronic equipment within the rack. It is understood that within the rack, the transport of heat from the actual source component (e.g., CPU) within the rack itself can be either liquid- or air-based (or any other heat transfer mechanism), but the heat rejection media to the building cooling device outside of the rack is liquid
Core
Used to identify the core set of architectural, computational processing elements that provide the functionality of a CPU
Core Network or Equipment
See communication equipment
Corps of Engineers
An agency of the U.S. Army that provides public engineering services in peace and war to strengthen national security, energize the economy, and reduce risks from disasters. Source: Unites States Army
Corrosive to metal
A substance or a mixture which by chemical action will materially damage, or even destroy, metals. Source: United Nations GHS
Cost–benefit analysis
Monetary assessment of all negative and positive impacts associated with a given action. Cost–benefit analysis enables comparison of different interventions, investments or strategies and reveals how a given investment or policy effort pays off for a particular person, company or country. Cost– benefit analyses representing society’s point of view are important for climate change decision-making, but there are difficulties in aggregating costs and benefits across different actors and across timescales. Source: IPCC
CPU
Central processing unit. Source: ASHRAE
CPU-intensive
SPEC uses often to mean applications that are primarily bound by the available processing power. Typically, these spend most of their time performing calculations, comparisons, or transformations and do little or no I/O and spend very little time in the operating system
CPU2000
CPU2000 is the current version of the CPU component benchmark suite from SPEC. It replaces CPU95
CPU2006
CPU2006 is the name given to the ongoing effort to replace the current CPU2000 product
CPU92
CPU92 is a now outdated CPU component benchmark suite from SPEC. This was replaced by CPU95
CPU95
CPU95 is an earlier version of the CPU component benchmark suite from SPEC, which replaced CPU92 and the even older CPU89. This suite has in turn been replaced by CPU2000
CRAC
Computer room air conditioner also a classification type of data center cooling for high heat density air cooling. Source: ASHRAE and NVIDIA
CRAH
Computer room air handler also a classification type of data center cooling for high heat density air cooling. Source: ASHRAE and NVIDIA
CRC
Cyclic redundancy check
Cross Connect
A group of connection points, often wall- or rack-mounted in a wiring closet, used to mechanically terminate and interconnect twisted-pair building wiring
CTW
Cooling tower water. Source: ASHRAE
Cubic Feet per Minute (CFM)
Commonly used to measure the rate of air flow in systems that move air
Cubic Feet Per Minute (CFM)
A measurement of airflow volume, determined by how many cubic feet of air pass by a stationary point in one minute. Source: Lennox
Cubic Meter Per Hour (CMH)
A measurement of airflow volume, determined by how many cubic meters of air pass by a stationary point in one hour. Note: In the country using metric system, air conditioning engineers use CMH instead of CFM. Source: Schneider Electric
Cubic Meters
Volume of air or liquids transferred typically heated to cooling tower. Source: ASHRAE
Data Center
A large group of networked computer servers typically used by organizations for the remote storage, processing, or distribution of large amounts of data. Source: Oxford Languages
Data Center
A building or portion of a building whose primary function is to house a computer room and its support areas. Data centers typically contain high-end servers and storage products with mission-critical functions
Data Center Availability
Probability that a data center will be operable at a future time (takes into account the effects of failure and repair/maintenance of the data center)
Data Center Electrical & Cooling Systems
Systems residing in, on and next to a Building includes CRAHs, PDUs, CDUs, piping, conduit, and other power/cooling distribution systems. Source: TGG
Data Center Energy Practitioner (DCEP)
The data center industry and DOE partnered to develop the Data Center Energy Practitioner (DCEP) Program. The DCEP training program certifies energy practitioners qualified to evaluate the energy status and efficiency opportunities in data centers. More information at https://datacenters.lbl.gov/dcep
Data Center Reliability
Probability that a data center system will be operable throughout its mission duration (only takes into account the effects of failure of the data center)
Data Center, Air-cooled
Facility cooled by forced air transmitted by raised floor, overhead ducting, or some other method; A data center with only air-cooled equipment
Data Center, Liquid- and Air-cooled
Data center with both chilled air and liquid available
Data Center, Liquid-cooled
Data center with only liquid-cooled equipment
Data Frame
Consists of the destination address, source address, length field, logical link control (LLC) data, PAD, and frame check sequence
Data Terminal Equipment (DTE)
Any source or destination of data connected to the local area network