Key performance indicator. Source: Intel
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 While many of the definitions are unchanged, some of the definitions may be out of date and some of the terms may no longer be in use in the Data Center industry.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.
KPI
KW
Kilowatt a typical size of a racked set of servers 5-60 KW. Source: ASHRAE
kWh
Kilowatts times hour Source: ASHRAE
L-C DCE
Liquid-Cooled Data Center Equipment (non-water). Source: TGG
Label
An appropriate group of written, printed, or graphic information elements concerning a hazardous product, selected as relevant to the target sector(s), that is affixed to, printed on, or attached to the immediate container of a hazardous product, or to the outside packaging of a hazardous product. Source: United Nations GHS
Label element
One type of information that has been harmonized for use in a label, e.g., pictogram, signal word. Source: United Nations GHS
LACP
Link aggregation control protocol
LADDIS
The name of a performance group that originated the benchmark that came to be known as SPEC SFS. The name is an acronym of the companies from the original members: Legato, Auspex, Data General, Digital, Interphase, and Sun Microsystems
LAG ID
Link aggregation group identifier
Latent Heat Load
See heat load, latent
LCDCE
Liquid Cooled Data Center Environment. Source: TGG
LCWG
Liquid Cooling Working Group of the Green Grid. Source: TGG
Leakage Airflow
Any airflow that does not flow along an intended path. Leakage airflow results in excess fan energy and may also result in higher energy consumption of refrigeration equipment
Leakage Current
Refers to the small amount of current that flows (or "leaks") from an output device in the off state caused by semiconductor characteristics
Libraries
In computer terms, a library is a collection of sub-routines provided by the operating system or development environment that can be used to perform certain common tasks, e.g., read something off of disk, create a window on the display, sort an array of values, calculate the cosine of a value, etc.
License Agreement
An agreement that each licensee accepts prior to use of a product. In the SPEC case, this agreement covers what can and cannot be done with the SPEC benchmarks. Usually stating that any public use of any SPEC metrics must come from tests that were in complete agreement with the run and reporting rules for that benchmark
Link
The transmission path between any two interfaces of generic cabling (from ISO/IEC 11801)
Link Aggregation Group (LAG)
A group of links that appear to a MAC client as if they were a single link. All links in a link aggregation group connect between the same pair of aggregation aystems. One or more conversations may be associated with each link that is part of a link aggregation group (see IEEE 802.3, Clause 43)
Link Partner
The device at the opposite end of a link segment from the local station. The link partner device may be either a DTE or a repeater (see IEEE 802.3, Clause 28)
Liquid
A substance or mixture which at 50 degrees Celsius has a vapour press of not more than 300 kPa (3 bar), which is not completely gaseous at 20 degrees Celsius or less at a standard pressure of 101.3 kPa. Source: United Nations GHS
Liquid Cooling
See cooling, liquid
Liquid- and Air-cooled Data Center
See data center, liquid- and air-cooled
Liquid-cooled Data Center
See data center, liquid-cooled
Liquid-cooled Electronics
See electronics, liquid-cooled
Liquid-cooled Rack
See rack, liquid-cooled
Liquid-cooled Server
See server, liquid-cooled
Liquid-cooled System
Conditioned liquid (e.g., water, etc., usually above dew point) is channeled to the actual heat-producing electronic equipment components and used to transport heat from that component where it is rejected via a heat exchanger (air to liquid or liquid to liquid) or extended to the cooling terminal device outside of the rack
Listed
Equipment, materials, or services included in a list published by an organization that is acceptable to the authority having jurisdiction and concerned with evaluation of products or services, which maintains periodic inspection of production of listed equipment or materials or periodic evaluation of services, and whose listing states that either the equipment, material, or service meets appropriate designated standards or has been tested and found suitable for a specified purpose (NFPA 2002e)
Liters
A metric unit of capacity, formerly defined as the volume of one kilogram of water under standard conditions, now equal to 1,000 cubic centimeters (about 1.75 pints). Source: Oxford Languages
Load
The amount of electricity supplied by a generating system at any given time. Source: Oxford Languages
Load Generator
Something that provides part of a workload to a SUT for a benchmark. Commonly in SPEC usage, this term applies to a client system that is used to drive the SUT over a LAN. However, this term can also be used to describe a process (either on a client or the SUT) which is generating a load for the benchmark
Load Level
For any benchmark which submits various amounts of work to a SUT, a load level is one such amount of work. This is usually in terms of expected throughput, such as "a load level of 100 operations per second was tried, but the SUT was not able to keep up and was only able to complete 80"
Local Area Network (LAN)
A computer network that spans a relatively small area. Most LANs are confined to a single building or group of buildings. However, one LAN can be connected to other LANs over any distance via telephone lines and/or radio waves. A system of LANs connected in this way is called a wide area network (WAN)
Lpm or L/m
Liters per minute. Source: ASHRAE
Mainframe
A high-performance computer made for high-volume, processor-intensive computing. This term is used for the processor unit, including main storage, execution circuitry, and peripheral units, usually in a computer center, with extensive capabilities and resources to which other computers may be connected so they can share facilities
Managed Service Provider Data Center
This was the earliest form of outsourcing which occurred when companies hired AT&T, IBM, and HP. This has evolved and there are a number of managed services providers that let companies manage some, or all, of their data center functions. This is more typically handled by IT and Corporate Real Estate is seldom involved. Source: SOIR
Management Information Base (MIB)
A repository of information to describe the operation of a specific network device
Manifolds
A pipe or chamber branching into several openings, a component of liquid cooling solutions. Source: Oxford Languages
Material Compatibility
A material's resistance to corrosion, rust or stains when it comes in contact with a chemical, a parameter of evaluation for fluids used to cool data center equipment. Source: Setra
MBH
Heat release rate in units of 1000 British thermal units (BTU) per hour
Mean Time to Repair (or Recover) (MTTR)
The expected time to recover a system from a failure, usually measured in hours
Measured Power
The heat release in watts
Media Access Control (MAC)
The data link sub-layer that is responsible for transferring data to and from the physical layer
Megawatt (MW)
A unit of power equal to one million watts, especially as a measure of the output of a power station. Source: Oxford Languages
Megawatt-hour (Mwh)
A unit of electrical energy which equals one megawatt of power used for one hour. Source: Oxford Languages
Memory
A component type of data center class server. Source: Intel
Memory
Internal storage areas in the computer. The term memory identifies data storage that comes in the form of silicon, and the word storage is used for memory that exists on tapes or disks. The term memory is usually used as a shorthand for physical memory, which refers to the actual chips capable of holding data. Some computers also use virtual memory, which expands physical memory onto a hard disk
Memory Unit, Data Storage
A solid state item which accepts and systematically retains digital input data in such a manner as to facilitate the rapid recovery of the stored information. The item is a component of an electronic computer system. Excludes MAGNETIC DRUM, DATA STORAGE and CORE MEMORY UNIT. For portable solid-state memory, see MEMORY, PORTABLE, SOLID STATE. [ FIIG=A23900;INC=53510 || DLIS || ISO 22745-11 Source: eOTD ECCMA Open Technical Dictionary is an ISO 22745 compliant dictionary managed by ECCMA
Meter (m)
the SI unit of length. It is defined by taking the fixed numerical value of the speed of light in vacuum c to be 299 792 458 when expressed in the unit m s-1, where the second is defined in terms of ΔνCs. Source: BIPM
Metric
The final results of a benchmark. The significant statistics reported from a benchmark run. Each benchmark defines what are valid metrics for that particular benchmark
Micro Data Center
a data center that incorporate all of the essential components you find in a typical data center, but in a scaled down deployment. All components are enclosed within one standard IT rack with plenty of room to house your sensitive IT equipment, servers, and the rack accessories of your choice. Typically, micro data centers support critical loads of no more than 100-150 kilowatts (kW). Components within the rack usually include: • Uninterruptible power supply (UPS) • Rack power distribution unit (rPDU) • Rack cooling unit and climatic controls with integrated heat rejection • Remote monitoring sensors and software Some micro data centers also include backup fan systems, physical security, fire suppression systems, shock absorption, and power conditioning. Optional accessories can often be added to tailor the solution to your unique needs. For example, you may be able to include cable management tools, blanking panels, or airflow management solutions. Source: Vertivxvi
Microprocessor
A chip that contains a CPU. The terms microprocessor and CPU are quite often used interchangeably
Midplane
Provides a fault-tolerant connection from the blade server to the server chassis and other components. The midplane replaces an average of nine cables typically required in rack and pedestal server configurations, eliminating excessive cables
Minimum Efficiency Reporting Value (MERV)
Previously there were several specifications used to determine filter efficiency and characteristics. ASHRAE has developed the MERV categories so that a single number can be used to select and specify filters
Mist
Liquid droplets of a substance or mixture suspended in a gas (usually air). Source: United Nations GHS
Mixture
A solution composed of two or more substances in which they do not react. Source: United Nations GHS
MLC
Mechanical load component per ANSI / ASHRAE Standard 90.4 – 2016 is calculated by the sum of all cooling, fan, pump, and heat rejection annual energy use divided by the data center ITE energy (annualized MLC) or the sum of all cooling, fan, pump, and heat rejection design power divided by the data center ITE design power (design MLC). Source: ANSI
MMF
Multimode fiber
Motherboard
The main circuit board of a computer. The motherboard contains the CPU, BIOS, memory, input/output ports, expansion slots, connectors for attaching additional boards and peripherals, and the controllers required to control those devices
Motherboard
A component type of data center class server. Source: Intel
MTBF
Mean time between failure
MTCO2e
Metric Tons of carbon dioxide equivalent. Source: United States Environmental Protection Agency
N2O
Nitrous oxide, an EPA targeted greenhouse gas. Source: United States Environmental Protection Agency
Nameplate capacity
A metal tag attached to a machine or appliance that contains information such as brand name, serial number, voltage, power ratings under specified conditions, and other manufacturer supplied data. Source: United States Energy Information Administration
Nameplate Rating
Equipment shall be provided with a power rating marking, the purpose of which is to specify a supply of correct voltage and frequency, and of adequate current-carrying capacity (IEC 60950, Clause 1.7.1)
Natural Convection Overhead (NOH)
An air distribution and cooling strategy in which cooling coils are suspended from the ceiling and air is circulated by natural convection with no fans or ducting
NEBS
Formerly network equipment-building system. Provides a set of physical, environmental, and electrical requirements for a central office (CO) of a local exchange carrier (LEC). NEBS is a trademark of Telcordia Technologies, Inc.
NEC
National Electric Code
Network Interface Card (NIC)
An adapter circuit board installed in a computer to provide a physical connection to a network. Also called adapter cards or NIC cards. [ KEY=104862;UNSPSC=43201404;V23.07 || IDEA || ISO 22745-11 COMPLIANCE Source: eOTD ECCMA Open Technical Dictionary is an ISO 22745 compliant dictionary managed by ECCMA
Network Switch
Network device that filters, forwards, and floods frames based on the destination address of each frame. The switch operates at the data link layer of the OSI model. [KEY=104918;UNSPSC=43222612;V23.07 || IDEA || ISO 22745-11 COMPLIANCE Source: eOTD ECCMA Open Technical Dictionary is an ISO 22745 compliant dictionary managed by ECCMA
NFPA
National Fire Protection Association
NGO
Non-Governmental Organization. Source: United Nations GHS
NIH
National Institutes of Health. Source: ASHRAE
NIOSH
National Institute for Occupational Safety and Health
NIOSH
National Institute for Occupational Safety and Health. Source: ASHRAE
Non-raised Floor
Facilities without a raised floor utilize overhead ducted supply air to cool equipment. Ducted overhead supply systems are typically limited to a cooling capacity of 100 W/ft2 (Telcordia 2001)
Object Code
Object code is commonly the product of running source code through a compiler. It is usually a binary representation of the program statements translated into a form that is understood natively by the processor
OCP
Open Compute Project. Source: OCP
OEM
Original equipment manufacturer. Source: ASHRAE
Open Systems Group (OSG)
Within SPEC, this group works on benchmarks for evaluating the performance of systems running open (or publicly defined) operating systems (e.g., UNIX and its derivations, as well as NT and VMS)
Open Systems Steering Committee (OSSC)
Executive decision-making body within the Open Systems Group
Operating pressure
Maximum internal fluid pressure recommended for safe, reliable operation. Special consideration for extreme temperature applications, or when in combination with high flow rates. An operating pressure of 0-120 psi (0 to 827.4 kPa) may be considered for water-cooling applications. Source: ASHRAE
Operating System
Operating systems perform basic tasks, such as recognizing input from the keyboard, sending output to the display screen, keeping track of files and directories on the disk, and controlling peripheral devices, such as disk drives and printers. It ensures that different programs and users running at the same time do not interfere with each other. The operating system is also responsible for security, ensuring that unauthorized users do not access the system. Operating systems provide a software platform on top of which other programs, called application programs, run
Operations, Administration, and Maintenance (OAM)
A group of network support functions that monitor and sustain segment operation, activities that are concerned with, but not limited to, failure detection, notification, location, and repairs that are intended to eliminate faults and keep a segment in an operational state and support activities required to provide the services of a subscriber access network to users/subscribers
OPS
Been specified by the benchmark standard
Optical Fiber
A filament-shaped optical waveguide made of dielectric materials
Original Design Manufacturer (ODM)
A company that designs equipment that is then marketed and sold to other companies under their own names, e.g., many IT equipment ODMs design and build servers in Taiwan and China
Original Equipment Manufacturer (OEM)
A company that manufactures equipment that is then marketed and sold to other companies under their own names
OSHA
Occupational Safety and Health Administration. Source: ASHRAE
OSHA
Occupational Safety and Health Administration
Owner's Program
A document that captures the facility's intent (mission) and performance requirements. ASHRAE Guideline 1-1996 states it is "the document that outlines the owner's overall vision for the facility and expectations of how it will be used and operated"
Oxidation Stability
The propensity of oils to form sludge and acid products during oxidation, a parameter of evaluation for fluids used to cool data center equipment. Source: ASTM
Parallelizable
The property of a computer program, or program segment, that allows for the parallel execution of parts of the same program. Parallel programming covers a wide range of degrees, from the very small grain (e.g., similar operations on multiple elements of the same array or matrix) to large grain (e.g., simultaneous execution of unrelated procedures)
Pascal (PA)
A unit of pressure equal to one newton per square meter. As a unit of sound pressure, one pascal corresponds to a sound pressure level of 94
Patch Cord
Flexible cable unit or element with connector(s) used to establish connections on a patch panel (from ISO/IEC 11801: 1995)
Patch Panel
A cross-connect designed to accommodate the use of patch cords. It facilitates administration for moves and changes (from ISO/IEC 11801: 1995)
Pause
A mechanism for full duplex flow control (see IEEE 802.3, Annex 3_1B)
PCB
Printed Circuit Board. Source: GEC
PCBA
Printed Circuit Board Assembly. Source: OCP
Peak
For SPEC's purposes, a peak configuration is one where the configuration is tuned especially to get the best result for a single, specific workload. Typically, this demonstrates the highest performance levels achievable. Peak is often used in combination with baseline configurations