Brief Summary
This glossary provides definitions for a wide range of terms related to data centers, covering aspects from infrastructure and power to cooling, security, and sustainability. It includes technical terms, acronyms, and industry jargon, offering a comprehensive reference for professionals and anyone seeking to understand data center operations and technology.
- Infrastructure and Power: Terms related to power distribution, backup systems, and electrical components.
- Cooling and Environmental Control: Definitions for cooling systems, airflow management, and environmental considerations.
- Security and Safety: Terms related to physical and digital security measures, as well as fire protection systems.
- Data Management and Networking: Definitions for data storage, networking technologies, and data center management practices.
- Efficiency and Sustainability: Terms related to energy efficiency metrics, green data center practices, and resource utilization.
[Terms: # - A]
This section defines terms starting with numbers and the letter "A." 2N redundancy ensures no single point of failure with complete component backup. "A" stands for Ampere, the unit of electric current. AaS (as a Service) is an operational model where IT services are delivered to businesses. AC (Alternating Current) is power delivered in sinusoidal waveform, favored over DC due to easy voltage transformation. AC/DC refers to alternating and direct current, respectively. ACAE (Air Conditioning Airflow Efficiency) measures heat removed per airflow. Access Points are hubs for wireless devices connecting to wired LANs. AHU stands for Air Handling Unit. Air-Sampling smoke detectors detect microscopic smoke particles. Air Mixing is the unintended mixing of hot and cold air. AI (Artificial Intelligence) enables machines to think and act autonomously. Airside Economizers use outside air for cooling when conditions allow. An Aisle is the open space between racks, ideally arranged for cold and hot aisles. Anti-Static environments reduce or prevent static electricity buildup. Arc Flash is current flow through air, releasing radiant energy. ASHRAE is the American Society of Heating, Refrigerating and Air-Conditioning Engineers. ATS (Automatic Transfer Switch) automatically switches electrical loads to backup power. Available Space is the total leasable space marketed. Auto Transfer Switch automatically transfers power sources.
[Terms: B]
This section defines terms starting with the letter "B." A Battery consists of electrically connected cells for required voltage and current. Big Data refers to datasets too large for typical database tools. Biometric Access uses physical characteristics for authentication. A Blade Server is a space and power-optimized computer. Blanking Panels improve cooling efficiency by blocking air transfer in empty rack spaces. Bonding is the permanent joining of metallic parts for electrical continuity. A Branch Circuit is the circuit conductors between the final overcurrent device and the outlet. BTU (British Thermal Unit) is used to rate air conditioners. Build-To-Suit is property developed for a specific tenant's needs. Burn-In is an extended test to detect problems. Bypass Airflow is conditioned air that doesn't reach equipment.
[Terms: C]
This section defines terms starting with the letter "C." A Cabinet is a device for holding IT equipment, also called a rack. CAC (Cold Aisle Containment) directs cooled air to rack inlets. CADE (Corporate Average Data Center Efficiency) is a data center efficiency metric. A Cage is an enclosure subdividing colocation space. Calibrated Vectored Cooling optimizes airflow in server systems. CapEx (Capital Expenditure) is the cost of purchasing capital equipment. Carrier Neutral data centers allow clients to choose any telecommunication provider. Carrier Hotels are primary internet exchange points. Category 6 Cable (Cat-6) is a cable standard for Gigabit Ethernet. CCTV (Circuit Television) is a private television system for security. Ceiling to Deck Height is the space between a suspended ceiling and the structural surface above. CFD (Computational Fluid Dynamics) predicts airflow and temperature. CFM (Cubic Feet per Minute) is a unit of flow rate. A Chilled Water System uses water as a cooling medium. A Chiller chills water to cool and dehumidify air. Chiller Feeds are a type of precision cooling system widely used in mid-sized to large IT environments. Closed-Coupled Cooling is installed adjacent to server racks. Cloud Computing delivers hosted services over the Internet. Cloud Storage API connects local applications to cloud storage. A Cold Aisle has rack fronts facing into it. A Cold Spot is an area with below-desired temperatures. Colocation is locating technology assets in an off-site data center. Commissioning uncovers deficiencies in design or installation. Concurrently Maintainable allows maintenance without disrupting operation. Condensate Piping removes water from dehumidification. A Condenser condenses vapor into liquid. Containment maintains a physical barrier between hot and cold aisles. Content Delivery Network accelerates content delivery. Converged Infrastructure relies on a vendor for pre-configured hardware and software. A Cooling Tower transfers heat to the atmosphere via water evaporation. CPU is a hardware device in a computer that executes all the instructions from the software. CR is a secure environment for equipment and cabling directly related to the critical load. CRAC (Computer Room Air Conditioning) controls air temperature and humidity. CRAH (Computer Room Air Handler) uses chilled water to cool air. Critical Load is computer equipment whose uptime is critical. Critical Cooling Load is the usable cooling capacity at the data center floor. A Cutout is an open area in a raised floor for airflow or cable feeds. CW stands for Chilled Water. CWR is the abbreviation for chilled water return. CWS is the abbreviation for chilled water supply. Cybersecurity protects systems and networks from digital attacks. Cybersecurity Systems protects networks, devices and data from unauthorized access or criminal use.
[Terms: D]
This section defines terms starting with the letter "D." D/H stands for Dehumidifying/Humidifying. A Data Center houses computer systems and associated components. A Data Center Administrator monitors systems and installs equipment. Data Center Bridging enhances Ethernet for data centers. A Data Center Shell is a building pre-qualified for power and telecom access. A Data Hall is the secure area housing technical infrastructure. Data Integrity ensures digital information is uncorrupted. Data Center Networking interconnects all data center resources. DC (Direct Current) is a non-time varying method of delivering power. DCaaS is the provision of off-site physical data center facilities and infrastructure to clients. DCIE is an efficiency measure calculated by dividing the IT equipment power consumption by the power consumption of the entire data center. Dedicated Hosting provides server capacity to single customers. Dehumidification removes moisture from air. Delta T is the temperature difference across a device. Direct Space is space offered for lease directly from the landlord or owner of a building. Dirty Power is an abnormality in the power quality being delivered to a system. Disaster Recovery resumes normal operations after a disaster. Discharge Rate is the rate at which current is delivered by a battery. Distribution is the way power is routed to various current-using sites or devices. A Distribution Cell is the cellular floor sections from which cables emerge into work areas. A Distribution Frame connects cabling for interconnection or cross-connections. A Distribution Panel provides a patch panel function. A Double Interlock Pre-Action Fire Sprinkler monitors piping for leaks and holds water from system piping. Downtime is a period of time that a system is unavailable or offline. Down Flow air conditioners discharge air downward. Draw Cap is a contractually determined limit on how much power customers can draw/use within their data center cages. DRaaS provides continuous data protection from your primary environment to your target site. Dropout is loss of equipment operation due to noise, sag or interruption. Dropout Voltage is the voltage at which a device fails to operate. Ducting carries heated or cooled air. DX is an abbreviation for direct expansion.
[Terms: E]
This section defines terms starting with the letter "E." An Economizer reduces energy consumption. Economization utilizes the local environment to aid in cooling of the IT load by natural means rather than use more energy. Edge Computing brings computations and data storage closer to the sources of data. An Edge Data Center is a smaller facility located close to the populations they serve. EFC (Equivalent Full Cabinets) is the number of full cabinets if all equipment were concentrated. Electronic Data Interchange securely transfers data via the Internet. Electrical Service connects the electric utility's cables to the building. An Emergency Power System provides backup power during outages. An Enterprise Data Center is a company-owned data center for internal data. EPO (Emergency Power Off) is a single disconnecting means for all power. ESD (Electrostatic Discharge) is more commonly known as ‘static discharge’. An ESD Wrist Strap grounds technicians to prevent static electricity buildup. Evaporative Cooling cools air by vaporizing water. Existing Inventory is the square footage of buildings that have received a certificate of occupancy and are able to be occupied by tenants. E-Waste is refuse from discarded electronic devices.
[Terms: F]
This section defines terms starting with the letter "F." Fault Current is the current that flows as a result of a short-circuit condition. Feeder Conductor are the conductors between the load side of the service equipment and the line side of the final branch circuit overcurrent device. Fire Rated has an official rating or designation as determined by the NFPA. A Fire Stop seals penetrations into a fire-rated area. A Firewall prevents unauthorized network access. Floor Drains provide an opening in a floor that drains water into a plumbing system. A Floor Puller lifts sections of flooring. A Floor Tile is part of a raised-floor system. A Flywheel stores rotational energy. A Fluid Cooler transfers heat energy from a flowing glycol stream to the outside atmosphere. Free Cooling uses the outside atmosphere for cooling. Frequency is the number of occurrences of a repeating event per unit of time, represented in hertz. A Fuel Cell derives energy from combustible substances. Full Service Rental Rate includes all operating expenses.
[Terms: G]
This section defines terms starting with the letter "G." A Generator converts mechanical energy to electrical energy. Generator Electrical Feeds are wires that feed from the electrical generator into the building structure. Glycol is ethylene glycol and water used as a heat removal medium. A Glycol Cooled System absorbs heat from the air and removes it from the room in the form of heated liquid water/glycol solution. GPH stands for Gallons per Hour. GPM stands for Gallons per Minute, a unit of flow rate. A Green Data Center is built considering energy efficiency and sustainability. Ground is a conducting connection to the earth. Ground Fault is an undesired current path between ground and an electrical potential.
[Terms: H]
This section defines terms starting with the letter "H." Hot Aisle Containment directs heated air to air conditioning equipment. Hall-POD is a module or a room, segmented area of a datacenter. Halon is a fire-extinguishing agent. Harmonic Distortion is distortion in the line voltage waveform. A Heat Exchanger transfers heat energy from one medium to another. HEPA is a type of vacuum air filter that catches a very high percentage of all particles that could damage or destroy sensitive data center equipment. HDG stands for Hot Dipped Galvanized. Horizontal Pathways connect telecommunications rooms to outlets. Hosting runs servers on behalf of another party. Hot Air Return is the path for hot air to return to the mechanical unit. A Hot Aisle has rack backs facing into it. Hot Aisle/Cold Aisle is an organized layout separating cooling and exhaust air. A Hot Gas Line connects a compressor to a condensing coil. HPDC (High-Performance Data Center) has above-average kW loading. A Hot Spot is an area with above-acceptable temperatures. Humidification introduces humidity to control electrostatic discharge. A Humidifier provides humidification. HVAC (Heating, Ventilating, and Air Conditioning) regulates temperature and humidity. A Hybrid Cloud combines public and private clouds. A Hyperscale Data Center houses critical compute and network infrastructure. Hybrid IT combines in-house data centers with private and/or public clouds.
[Terms: I]
This section defines terms starting with the letter "I." IEEE is the Institute of Electrical and Electronics Engineers. In-Row Cooling increases cooling efficiency by maximizing airflow. Inergen is an environmentally green fire suppression agent. Infrared Scanning locates defects in electrical equipment. Infrastructure as a Service delivers computer infrastructure as a service. Inlet Air is the air entering the referenced equipment. Inrush Current is the initial surge of current experienced before the load resistance of impedance increases to its normal operating value. Intelligent Data Center is optimized and automated using AI, machine learning and IoT devices. Intelligent Power Management optimizes power distribution and use. An Interconnection System connects two electrical systems for energy transfer. An Intermediate Distribution Frame manages telecommunications cable. An Internet Service Provider provides access to the Internet. An Inverter converts battery DC output to AC. An IP Address identifies each computer using the Internet Protocol.
[Terms: J - K]
This section defines terms starting with the letters "J" and "K." A Junction Box provides space to connect and branch enclosed conductors. kW stands for Kilowatts, one thousand watts. kWh stands for Kilowatt-Hour, one thousand watt hours. kVA stands for Kilovolt Amperes = voltage x current. KVM is an interface technology that enables users to access multiple servers remotely from one or more KVM sites.
[Terms: L]
This section defines terms starting with the letter "L." Latent Cooling is the process of condensing water out of air, then evaporating the water later. Latent Cooling Capacity is the fraction of total capacity an air conditioner or air handler uses to condense liquid water from the air stream being cooled. Latent Heat of Evaporation is a term describing the amount of latent heat transferred during a liquid / vapor phase change for a particular substance. A Lead Acid Battery is the assembly of one or more cells with an electrolyte, based on dilute sulfuric acid and water, a positive electrode of lead dioxide, and negative electrodes of lead. Leak Detection monitors and alarms in the presence of moisture. Leasing Activity is the volume of square footage that is committed to, and signed under, a lease obligation for a specific building or market in a given period of time. Leasing Space is all the space that has a financial lease obligation. A Lightning Arrester protects equipment from high voltage surges. A Lights Out Server Room functions as a center to house various servers. Line Noise is distortions superimposed on the power waveform. Liquid Cooling uses a liquid evacuate heat. A Liquid Line is a refrigerant pipe carrying liquid refrigerant connected the output side of the condensing coil and to the input side of the expansion valve. Load is the demand placed on a system. Load Balancing distributes workload across multiple computers. Load Fault is a malfunction that causes the lead to demand abnormally high amounts of current from the source. Load Shedding distributes demand for electrical power across multiple power sources. A Load Bank creates an electrical load. A Low Voltage System identifies safety considerations of an electricity supply system based on the voltage used.
[Terms: M]
This section defines terms starting with the letter "M." Machine Learning allows data center operations to effortlessly track equipment performance and make data-driven decisions about equipment replacement by developing and studying statistical algorithms that can learn from data and perform tasks without explicit instructions. MAH stands for Makeup Air Handler, an air handler that conditions and delivers outside air into an occupied space. A Main Distribution Frame is a panel where communication cables are terminated and connected. Make-Up Air is outside air introduced into the interior. Managed Hosting leases dedicated servers and hardware to a single client. Managed Services manages assets or objects on behalf of a customer. A Mantrap is a small room between two sets of doors for secure access. A Manual Transfer Switch transfers electrical loads to a standby power source. Maximum Temperature Rate of Change is an ASHRAE standard for stable air temperatures. Mass Market Hosting provides services such as web hosting and domain registration. MBP/MBC stands for Maintenance Bypass Panel/Maintenance Bypass Cabinet. MCB stands for Main Circuit Breaker. MDF is commonly a steel rack that allows for the connection of networks within a plant or facility to outside cables and other equipment. Mean Time Between Failures is the mean time between failures of a system. Mean Time to Repair is the maximum time to recovery after an equipment failure. Memory Overcommit allows a virtual machine to use more memory space than the physical host has available. MERV is Minimum Efficiency Reporting Value, ASHRAE 52.2, for air filtration measured in particulate size. Metered Power measures power consumption to ensure the customer only pays for the amount of power used over a designated period of time. A Micro Data Center is essentially an edge data center pushed to the extreme, e.g., a small office closet. Modular, Non-Scalable UPS can modularly increase power capacity. Multiprocessing utilizes two or more central processing units in a single computer system. Multi-Tenant buildings house more than one tenant at a given time. MW stands for Mega Watt, a measure of power equal to one million watts.
[Terms: N]
This section defines terms starting with the letter "N." N+1 Redundancy provides a spare component in case of failure. NEBS are Network Equipment-Building System design guidelines. NEC is the National Electrical Code. Net Absorption is the net change in occupied space over a given period of time. Net Rental Rate excludes certain expenses that a tenant could incur in occupying office space. Network Cabinets hold a series of controllers. Network Cross Connections bridge a telecommunications vendor with a customer’s computer environment inside a data center. New Space refers to space that has never been occupied and/or leased by a tenant. NFPA is the National Fire Protection Association. Nominal Cooling Capacity is the total cooling capacity of air conditioning equipment, includes both latent cooling and sensible cooling capacities.
[Terms: O]
This section defines terms starting with the letter "O." Occupied Space is space that is physically occupied by a tenant. OCP stands for Overcurrent Protection, overcurrent exists when current exceeds the rating of equipment or the ampacity of a conductor. OLA is a contract defining how various IT groups within a company plan to deliver a service or set of services. OpEx stands for Operating Expense, the ongoing expenses related to operating the data center. Overcooling is a situation where air is cooled below optimum levels.
[Terms: P]
This section defines terms starting with the letter "P." Packet Acceleration achieves better throughput on an Internet connection than standard TCP achieves, without modifying the end applications. A Parallel Generator System provides large amounts of stand-by power or emergency power by incorporating multiple generators in parallel via a series of switching and controls. Parasitic Load is the power and cooling load for all ancillary equipment and common area operation. A Pedestal is the vertical component of the raised-floor, which supports the flooring system. PDU stands for Power Distribution Unit typically refers to either to the transformer/breaker panel that is used between a UPS supplying voltage higher than that used by the IT equipment and the cabinets. PH stands for Phase, a term that describes the relationship between multiple time-varying waveforms which have a constant frequency but differ in their position relative to time. Platform as a Service rents hardware, operating systems, storage and network capacity over the Internet. Plenum refers to the area where air circulates in systems running heating and air conditioning units. A Pole is a row of power receptacles with power supplied from a PDU. Pole Position is a power receptacle on a pole. A Potential Transformer transforms electrical potential from one level to another with a specific ratio. Power is defined as the rate at which electrical energy is transferred by an electric circuit. Power Cycling is the process of turning hardware off and then turning it on again. Power Density is electrical power used in a space divided by the area of the space. Power Factor is the ratio of energy consumed versus the product of input voltage times input current. A Powered Shell is a data center facility that has it’s exterior completed and is connected to power and connectivity, but has an unfinished interior, allowing for flexibility and adaptability for users’ needs. Prefabrication is a manufacturing process generally taking place at a specialized facility, in which various materials are joing to form a component part of a final installation. Preleased Space is the amount of space in a building that has been leased prior to its construction completion date, or certificate of occupancy date. Premium Colocation are Tier III+ data centers that generally qualify as extremely desirable and command the highest rents or sale prices compared to other buildings in the same market. Pre-Action is an Action involved in a dry system prior to actually flooding the pipe with water and potentially discharging into the protected space. A Pre-Action Fire Sprinkler is a fire sprinkler system that employs the basic concept of a dry pipe system in that water is not normally contained within the pipes. Precision Air Conditioning is specifically designed to cool information technology equipment in a data center or server room. Pressure Differential is the difference in pressure between two locations in the data center. Preventative Maintenance is regularly-performed maintenance on a piece of equipment to lessen the likelihood of it failing. Primary Loop refers to the water loop which cools the condenser side of a chiller. A Private Cloud is a proprietary computing architecture that provides hosted services to a limited number of people behind a firewall. PUE measures the efficiency of power usage in a data center. A Public Cloud infrastructure is available to the general public and is owned by a large provider of cloud services. A Pump Package is a pump or pumps and enclosure or skid used in coordination with a cooling system to circulate condenser water or glycol on applicable systems. Pumps are a pump and enclosure used to circulate condenser water or glycol on applicable systems.
[Terms: R]
This section defines terms starting with the letter "R." Rack is a device for holding IT equipment, also called a cabinet. RAH stands for Recirculation Air Handler, a device that circulates air but does not cool the air. RAT is the air returning to air conditioning equipment. A Raised Floor is a system of pedestals, stringers, and floor tiles that create an elevated floor environment. Recirculation is air which exits IT equipment and then re-enters either the same IT equipment or another piece of IT equipment without being cooled. Redundancy is the duplication of critical infrastructure support systems with the intention of backing up the primary systems and protecting against system down-time due to failure. Redundancy is a backup system or component. Refrigerant is the working fluid used in the refrigeration cycle. Relative Humidity is the amount of water vapor contained in air relative to the maximum amount the air is capable of holding. Reliability is classically defined as the probability that some item will perform satisfactorily for a specified period of time under a stated set of conditions. Remote Data Backup is the process of backing up data created by remote and branch offices and storing it securely. Remote Replication is the process of copying production data to a device at a remote location for data protection or disaster recovery purposes. Return Air is the heated air returning to air conditioning equipment. RFI stands for Radio Frequency Interference. Rh stands for Relative Humidity. A Rope Detector is a leak detection instrument used to detect the presence of moisture along its length. Row-Based Cooling solutions provide cooling directly to multiple adjacent cabinets. RPM is used for measuring fan speeds/flywheel rotation. RPP stands for Remote Power Panel. RTU stands for Rooftop Unit, an air handler designed for outdoor use mounted on a rooftop.
[Terms: S]
This section defines terms starting with the letter "S." S+S stands for System plus system. SAN stands for Storage Area Network. Scalability is the ability for the required infrastructure to be enlarged or handle increased capacity input without efficiency or reliability being compromised. SCFM stands for Standard Cubic Feet per Minute, the volumetric flow rate of a gas corrected to standardized conditions of temperature, pressure and relative humidity. Screen Scraping is a data collection method used to gather information shown on a display to use for another purpose. Secondary Loop refers to the water which is used to cool the heat exchangers in AHUs and is cooled via the expansion unit in a chiller. SDDC is a data storage facility where networking, storage, CPU and security are virtualized and delivered as a service. Seebeck Effect is a phenomenon in which a temperature difference between two dissimilar electrical conductors or semiconductors produces a voltage difference between the two substances. Sensible Cooling Capacity is the amount of heat energy the air conditioner can be expected to remove from an environment with computer or server equipment. Sensible Heat is defined as the heat energy that causes a change in temperature of a substance but does not contribute to a change in state for the substance. Sensible Heat Ratio is the ratio between an air conditioner's sensible heat removal capacity and its total heat removal capacity. Server Cabinets are a cabinet designed to hold a network device that combines hardware and software to provide and manage shared services and resources on the network. A Server Room is a location specifically designed to house a high concentration of information technology equipment. A Service Provider is an organization that provides cellular or local exchange telecom services, cloud data center networking services, or other internet-related services. Set Point is the value against which the variable that is being controlled is compared. Shared Hosting is where customers share server capacity. Short Cycling is chilled airflow returning to cooling units without passing through IT equipment, also referred to as bypass. Single Phase electric power refers to the distribution of electric power using a system in which a single leg or phase is taken from a three-phase source either by connection between a phase and neutral or by connecting the load between two phases. Single-Tenant buildings are occupied, or intended to be occupied by a single tenant. A Smart Data Center environment where intelligent, remote, self-service capabilities deliver an elevated level of fluidity to enrich real-time visibility, access and control of critical data center capabilities and assets. Spare/Space are terms used to identify unused electrical circuits in a panel. A Spike is a sudden marked jump in voltage, which can damage electronics and corrupt or destroy data. A Spike/Surge Protector is an appliance designed to protect electrical devices from voltage spikes. A Spot Detector is a leak detection instrument designed to detect moisture that accumulates directly under the detector. SSID stands for Service Set Identifier. Standard Temperature and Pressure refers to nominal conditions in the atmosphere at sea level. A Standby Generator is the main component in a back-up electrical system that operates automatically. A Static Transfer Switch selects between two or more sources of power and provides the best available power to the critical load. Step Down Transformers are a transformer that reduces voltage - an electrical device by which alternating current of one voltage is changed to another voltage. A Stringer is the horizontal component of the raised-floor, which supports the floor panels. Structured Data is data that has a defined length and format, such as number and dates, and is usually stored in a database. STS stands for Static Transfer Switch, a solid state device which transfers the feed of power from one source to another source such as from the incoming utility to a generator. Sub-Floor is the open area underneath a raised computer floor, also called a sub-floor plenum. A Suite is hard-walled rooms within a data hall used for customers who require more data space. Supply Air is the cooled airflow emitted from air conditioning equipment. A Surge is a prolonged over-voltage condition. Switchgear is Electrical Distribution hat breaks out power from high to medium to low voltage.
[Terms: T]
This section defines terms starting with the letter "T." A Thermistor is a type of resistor with resistance varying according to its temperature. Thermoelectric Cooling is a way to remove thermal energy from a medium, device or component by applying a voltage of constant polarity to a junction between dissimilar electrical conductors or semiconductors. THHN is a type of wire primarily used in electrical installations in conduit and is not rated for use in a plenum space outside of conduit do to the PVC jacket. Three-Phase refers to an electric power system having at least three conductors carrying voltage waveforms that are 2ð/3 radians offset in time. Tier I: A Tier 1 data center is a basic server room implementing the general guidelines for computer system installations. Tier II: A Tier 2 data center Includes all requirements of Tier 1, plus a guarantee of 99.741 percent availability with redundant site infrastructure capacity components. Tier III: In addition to fulfilling requirements of Tiers 1 and 2, Tier 3 data centers provide dual-powered IT equipment to receive data from multiple independent distribution paths with an increased availability of 99.982 percent guaranteed. Tier IV: Tier 4 data centers include the components of the first three Tiers with the addition of independently dual-powered cooling equipment. Ton: A ton is heat energy equal to 12,000 BTUs and is the amount of heat energy required to melt 2000 pounds of ice in one hour. Tons: Ton A measurement of heat energy commonly used historically to measure heat loads in data centers and IT rooms in North America. Topology: Network Design, planning data center operations and enhancement require both physical and logical topologies. Traditional, Non-Scalable UPS: Based on a particular size rating. Transformer: An electro-magnetic device used to change the voltage in an alternating current electrical circuit. Transient Voltage Surge Suppressor: A device used to reduce voltage surges. Transition Operating System: An operating system is an interface between hardware and user; it is responsible for the management and coordination of activities and the sharing of the limited resources of the computer. Turning Vane: An air management device installed in many floor stands to assist in redirecting the flow of cooling air from vertical to horizontal as it exits the computer room air conditioner or air handler. TVSS: Transient volt surge suppression; shunt to ground over volt spikes to prevent electrical fires and/or system failures.
[Terms: U]
This section defines terms starting with the letter "U." U: A unit of space in a rack, equal to 1.75″. UL: Underwriters Laboratories, Inc. Unified Computing System: A unified computing system is a data center architecture that integrates computing, networking and storage resources to increase efficiency and enable centralized management. Uninterruptible Cooling: The process of continued heat removal from the IT room or data center during equipment failure or power failure to preclude thermal damage and data loss due to equipment overheating. Unstructured Data: Data which does not follow a predefined data model or fit into relational databases, such as video, text, email and social media. Up Flow: A term applied to air conditioners and air handlers that discharge air in an upward direction. UPS: UPS is a battery-powered device that sends power to a computer system when the normal power source fails. UPS Power: Uninterrupted Power Supply, a critical data center component that cleans incoming “dirty” power from the commercial utility power and provides instantaneous back-up power when a main power source fails. Usable KVA per Circuit: De-rating of available Kilo-volt-amps to usable amps to prevent circuit overloads and fires. Usable Kw per Circuit: De-rating of available Kilo-watts to usable amps to prevent circuit overloads and fires. Usable VA per Circuit: De-rating of available volt-amps to usable amps to prevent circuit overloads and fires. Utility Power: Power from the local utility company. Utility Storage: A service model in which a provider makes storage capacity available to an individual, an organization or a business unit on a pay-per-use basis.
[Terms: V]
This section defines terms starting with the letter "V." V: Volt, a unit of electrical potential. VA: Volt-Amp, a unit of apparent power. Valve Regulated Sealed Cell : A battery in which the cells are closed but have a valve which allows the escape of gas if the internal pressure exceeds a predetermined value. Vapor Barrier: Paint, plastic sheeting, floor, or ceiling material specifically designed to minimize the migration of humidity into or out of an area. Venting: The controlled or accidental release of gas from a battery cell. VESDA System : Stops fires in a specific area before they can spread to other areas of the data center. VFD: Variable Frequency Drive, a device which supplies AC power of varying frequency, typically used to control the speed of induction motors. Virtualization: Virtualization is a framework or methodology of dividing the resources of a computer into multiple execution environments. VMware Backup: VMware backup is the copying of data on a virtual machine in a VMware environment to prevent data loss. VoIP: Voice over Internet Protocol. Voltage: Electrical force or potential, a technical synonym for voltage is emf or "electromotive force."
[Terms: W]
This section defines terms starting with the letter "W." W: Watt, a unit of power, commonly used in electrical discussion, watts are the product of potential and current . Water-Cooled System: A water-cooled system uses water instead of air as a condensing medium. Water Cooling: Water cooling is a method used to lower the temperatures of computer processors, and sometimes other components such as graphics cards, using water rather than air as the cooling medium. Water Detector: A device used to sense the abnormal presence of liquid water due to a leak or condensation. Waterside Economizer: A system which uses a source other than a chiller to cool the secondary loop water used by the AHUs. Wet-Bulb Temperature: The temperature of the air measured using a wet-bulb thermometer, that is, the temperature to which a wet surface can be cooled by evaporation. Wg: – Inches of water column, a unit of pressure based on the height of a column of water supported by the pressure differential between the top and bottom of the column. White Box Server: A data center computer that is not manufactured by a well-known, brand-name vendor. Wholesale Data Center: Sell data center space in large capacities. Wholesale Turnkey: A datacenter that is designed, supplied, built, or installed fully complete and ready to operate. Work Cell: The area of a rack and the related area immediately in front of and behind the rack. WPSF: Watts per Square Foot, a unit of power density. WUE: Water Usage Effectiveness, a sustainability metric defined by The Green Grid, which is a measure of the water used on-site for data center operations including humidification and on-site evaporation for cooling or energy production.
[Terms: X - Z]
This section defines terms starting with the letters "X," "Y," and "Z." There are no defined terms for "X" and "Y." Zinc Whiskers: The name given to very small structures of zinc that resemble hairs.
