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IEEE 802.3 physical layer specification for a 1000 MB/s CSMA/CD LAN using four pairs of Category 5 balanced copper cabling (see IEEE 802.3, Clause 40)

IEEE 802.3 physical coding sublayer for 10 GB/s operation over XAUI and four lane PMDs (see IEEE 802.3, Clause 48)

American Conference of Governmental Industrial Hygienists

Generally, a measure of the noise level in an environment or from a sound source. For a point in an environment, the quantity is sound pressure level in decibels (dB). For a sound source, the quantity is sound power level in either decibels (dB) or bels (B). Either of these quantities may be stated in terms of individual frequency bands or as an overall A-weighted value. Sound output typically is quantified by sound pressure (dBA) or sound power (dB). Densely populated data and communications equipment centers may cause annoyance, affect performance, interfere with communications, or even run the risk of exceeding OSHA noise limits (and thus potentially cause hearing damage), and reference should be made to the appropriate OSHA regulations and guidelines (OSHA 1996). European occupational noise limits are more stringent than OSHA's and are mandated in EC Directive 2003/ 10/EC (European Council 2003)

An instance of a MAC-physical layer entity within an aggregation system (see IEEE 802.3, Clause 43)

A device that supports automatic switching between multiple physical layer technologies (see IEEE 802.3, Clause 28)

See cooling, air

The temperature measured at the inlet at which air is drawn into a piece of equipment for the purpose of conditioning its components

Air conditioners are most efficient when the warmest possible air is returned to them. When cooler-than-expected air is returned to the air conditioner, it will perhaps mistakenly read that as the space temperature being satisfied. This air short-cycling is because the air is not picking the heat from the space before returning to the air conditioner (see also Air, Bypass)

Air diverted around a cooling coil in a controlled manner for the purpose of avoiding saturated discharge air. On an equipment room scale, bypass air can also refer to the supply air that short-cycles around the load and returns to the air handler without producing effective cooling at the load

Air treated to control its temperature, relative humidity, purity, pressure, and movement

Air extracted from a space and totally or partially returned to an air conditioner, furnace, or other heat source

See electronics, air- and liquid-cooled

See server, air- and liquid-cooled

See electronics, air-cooled

See system, air-cooled

See hot aisle/cold aisle

A discrepancy between the actual and desired characteristics of an item. This definition is derived from ANSI T1.416-1999 and ANSI T1.105-1995, which take precedence

A collection of data items usually laid out linearly in memory for simple access with an integer index from the base of the array. Many scientific applications use arrays to contain the dataset that they are analyzing. The larger the dataset, the larger the array size needs to be to fit the data

Formerly the American Society for Testing and Materials (ASTM)

The algorithm that allows two devices at either end of a link segment to negotiate common data service functions (see IEEE 802.3, Clause 28)

The date upon which that part of the system becomes generally available, that is available to anyone willing to pay the appropriate price and take immediate delivery

A cable consisting of one or more metallic symmetrical cable elements (twisted pairs or quads) (from ISO/IEC 11801)

For SPEC's purposes, baseline refers to a configuration that is more general and hopefully simpler than one tuned for a specific benchmark. Usually a baseline configuration needs to be effective across a variety of workloads, and there may be further restrictions, such as requirements about the ease-of-use for any features utilized. Commonly baseline is the alternative to a peak configuration.

Vented lead-acid battery

A unit of signaling speed expressed as the number of times per second the signal can change the electrical state of the transmission line or other medium. Depending on the encoding strategies, a signal event may represent a single bit, more, or less than one bit. Contrast with bit rate, bits per second (from IEEE 610.7-1995 [B38])

A reference point. Originally, a mark on a workbench used to compare the lengths of pieces so as to determine whether one was longer or shorter than desired. For computers, a benchmark is a test, or set of tests, designed to compare the performance of one computer system against the performance of others. A benchmark is not necessarily a capacity planning tool. That is, benchmarks may not be useful in attempting to guess the correct size of a system required for a particular use. In order to be effective in capacity planning, it is necessary for the test to be easily configurable to match the targeted use. In order to be effective as a benchmark, it is necessary for the test to be rigidly specified so that all systems tested perform comparable work. These two goals are often at direct odds with one another with the result that benchmarks are usually useful for comparing systems against each other, but some other test is often required to establish what kind of system is appropriate for an individual's needs

Bit error ratio tester

Basic input/output system. The BIOS gives the computer a built-in set of software instructions to run additional system software during computer boot-up

The ratio of the number of bits received in error to the total number of bits received

A modular electronic circuit board, containing one, two, or more microprocessors and memory, that is intended for a single, dedicated application (such as serving web pages) and that can be easily inserted into a space-saving rack with many similar servers. One product offering, for example, makes it possible to install up to 280 blade server modules vertically in a single floor-standing cabinet. Blade servers, which share a common high-speed bus, are designed to create less heat and thus save energy costs as well as space

An air-moving device (also see fan)

A layer 2 interconnection device that does not form part of a CSMA/CD collision domain, but conforms to the ISO/IEC 15802-3: 1998 [ANSI/IEEE 802.1D, 1998 Edition]. A bridge does not form part of a CSMA/CD collision domain, but rather appears as a media access control (MAC) to the collision domain (see also IEEE 100)

British thermal units. The amount of heat required to raise one pound of water one degree Fahrenheit, a common measure of the quantity of heat

See bus, power

See air, bypass

See air, cabinet

Category 3 balanced cable

Constant air volume

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

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.

* 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)

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

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

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

* 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

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

A computational technology that enables you to study the dynamics of fluid flow and heat transfer numerically

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

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)

Heat exchanger in which vapor is liquefied (state change) by the rejection of heat as a part of the refrigeration cycle

Removal of heat

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

Used to identify the core set of architectural, computational processing elements that provide the functionality of a CPU

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

CPU2006 is the name given to the ongoing effort to replace the current CPU2000 product

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

A group of connection points, often wall- or rack-mounted in a wiring closet, used to mechanically terminate and interconnect twisted-pair building wiring

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

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

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 with only liquid-cooled equipment

Any source or destination of data connected to the local area network

The set of inputs for a particular benchmark. There may be more than one dataset available for each benchmark each serving a different purpose (e.g., measurement versus testing) or configured for different problem sizes (small, medium, large, etc.

Decibels referenced to 1.0 mW

The process of removing moisture from air

See temperature, dew-point

A fluid that is a poor conductor of electricity

Hard disk drive installed in a piece of data communications equipment, such as a personal computer, laptop, server, or storage product

Two definitions for diversity exist, diverse routing and diversity from maximum:
* Systems that employ an alternate path for distribution are said to have diverse routing. In terms of an HVAC system, it might be used in reference to an alternate chilled water piping system. To be truly diverse (and of maximum benefit), both the normal and alternate paths must each be able to support the entire normal load.
* Diversity can also be defined as a ratio of maximum to actual for metrics such as power loads. For example, the nominal power loading for a rack may be based on the maximum configuration of components all operating at their maximum intensities. Diversity would take into account variations from the maximum in terms of rack occupancy, equipment configuration, operational intensity, etc., to provide a number that could be deemed to be more realistic

An advanced version of synchronous DRAM (SDRAM) memory now used in most servers. DDR-SDRAM, sometimes called SDRAM II, can transfer data twice as fast as regular SDRAM because it can send and receive signals twice per clock cycle

Refers to a type of air conditioning system that discharges air downward directly beneath a raised floor commonly found in computer rooms and modern office spaces

See temperature, dry-bulb

A small circuit board that usually holds memory chips. A single in-line memory module (SIMM) has card edge connections that are connected to the same signals on both sides of the PCB, whereas a DIMM has different signals on each side of the PCB

Equipment cooling class

A ducting arrangement and automatic control system that allow a cooling supply fan system to supply outdoor (outside) air to reduce or eliminate the need for mechanical refrigeration during mild or cold weather

See communication equipment

The ratio of the output to the input of any system. Typically used in relation to energy. Smaller amounts of wasted energy denote high efficiencies

See bus, power

Valve regulated lead-acid (VRLA) cells of this design are constructed with a controlled volume of liquid electrolyte contained in a highly absorbent, blotter-like separator positioned between closely spaced plates. This non-woven separator distributes the electrolyte uniformly and maintains it in contact with the plate active material, while permitting the passage of oxygen evolved during charging. Cells with absorbed electrolyte technology have inherently low internal resistance and can be designed to provide a very high-rate, short-duration current. Cells with absorbed electrolyte are also known as absorbed glass mat (AGM) types

The ability of electronic equipment or systems to operate in their intended operational environments without causing or suffering unacceptable degradation because of electromagnetic radiation or response

Electronic equipment that uses both air and liquid

Electronic equipment that is directly cooled by liquid

Electromagnetic interference

The ratio of net equipment cooling capacity in BTU/h to total rate of electric input in watts under designated operating conditions. When consistent units are used, this ratio becomes equal to COP (see also coefficient of performance)

Refers to, but not limited to, servers, storage products, workstations, personal computers, and transportable computers. May also be referred to as electronic equipment or IT equipment

Manufacturer's specifications generally reference a range in which a piece of equipment CAN function. A recommended range refers to the range at which equipment is the most efficient and realizes the least amount of wear and tear, extending its useful life

Equipment conditioned by removal of heat using air

A networking system that enables high-speed data communication over coaxial cables

Condenser in which the removal of heat from the refrigerant is achieved by the evaporation of water from the exterior of the condensing surface induced by the forced circulation of air and sensible cooling by the air

As an adjective, executable means that the described item can be executed. In computer talk, executable has been also used as a noun, where it means an executable program, or in other words, something that is ready to run without further modification. Commonly, the term executable is used to refer to the binary file that is the final result of compiling source code

A heat sink with a fan directly and permanently attached

Frame check sequence

An architectural term that refers to the arrangement, proportion, and design of window, skylight, and door systems within a building

A pre-defined set of files that are used within a benchmark workload. Usually a fileset has specific characteristics that are relevant to how the benchmark performs its work

Software that has been encoded onto read-only memory (ROM). Firmware is a combination of software and hardware. The code or data programmed into ROMs, PROMs, EPROMs, and flash memory is firmware

A class of arithmetic, typically used in scientific applications. Actually much like the values displayed by a calculator, the values can range from very large down to minute fractions but only the first several digits are available. Floating point is commonly used when the values being calculated can be very large - into the billions - or else involve fractions, e.g., the number of miles from earth to the next galaxy (billions and billions) or the precise temperature of a feverish baby (101.8). Floating point is the alternative to integer. For the purposes of classification for the CPU benchmarks, SPEC classifies an application to be a floating point application if that application typically spends 10% or more of its time in calculating floating point value

Amount of some quantity flowing across a given area (often a unit area perpendicular to the flow) per unit time. The quantity may be, for example, mass or volume of a fluid, electromagnetic energy, or number of particles

The complete documentation of a benchmark's results along with the relevant system and benchmark configuration information. There should be sufficient detail and coverage for someone else to be able to reproduce the tests. Each result available on this server has such a disclosure available

A hardware or software setup that translates between two dissimilar protocols, or commonly, any mechanism for providing access to another system

A mean (average value) that is obtained through the use of multiplication and Nth roots rather than by addition and division. To calculate, take the Nth root (the power of 1/N) of the product of all N terms. The geometric mean has the interesting property that a certain percentage change in any one of the terms has the same effect as the same percentage change in any of the other terms and even successive changes in the same term will have the same effect as if the changes were instead spread over other terms. What this means in benchmarking terms is that a 10% improvement in one benchmark has the same effect on the overall mean as a 10% improvement on any of the other benchmarks and that another 10% improvement on that benchmark will have the same effect as the last 10% improvement. Thus no one benchmark in a suite becomes more important than any of the others in the suite

Device to transfer heat between two physically separated fluids
* Counterflow heat exchanger: Heat exchanger in which fluids flow in opposite directions approximately parallel to each other
* Cross-flow heat exchanger: Heat exchanger in which fluids flow perpendicular to each other
* Heat pipe heat exchanger: See heat pipe
* Parallel-flow heat exchanger: Heat exchanger in which fluids flow approximately parallel to each other and in the same direction
* Plate heat exchanger or plate liquid cooler: Thin plates formed so that liquid to be cooled flows through passages between the plates and the cooling fluid flows through alternate passages

Calculated by using product measured power divided by the actual area covered by the base of the cabinet or equipment

The heat load that causes a change in temperature

Component designed to transfer heat from an electronic device to a fluid. Processors, chipsets, and other high heat flux devices typically require heat sinks

High-efficiency particulate air

Includes scientific workstations, supercomputer systems, high speed networks, special purpose and experimental systems, the new generation of large-scale parallel systems, and application and systems software with all components well integrated and linked over a high speed network

Executive group within HPG. Currently, HPG and HPSC are the same (i.e., all HPG members are part of HPSC)

An air distribution system that is used by some long-distance carriers in North America. This system introduces the supply air horizontally above the cold aisles and is generally utilized in raised-floor environments where the raised floor is used for cabling

* A common arrangement for the perforated tiles and the data communications equipment. Supply air is introduced into a region called the cold aisle
* On each side of the cold aisle, equipment racks are placed with their intake sides facing the cold aisle. A hot aisle is the region between the backs of two rows of racks
* The cooling air delivered is drawn into the intake side of the racks. This air heats up inside the racks and is exhausted from the back of the racks into the hot aisle

High-performance computing

Water vapor within a given space
* Absolute humidity: The mass of water vapor in a specific volume of a mixture of water vapor and dry air.
* Relative Humidity: Ratio of the partial pressure or density of water vapor to the saturation pressure or density, respectively, at the same dry-bulb temperature and barometric pressure of the ambient air. Ratio of the mole fraction of water vapor to the mole fraction of water vapor saturated at the same temperature and barometric pressure. At 100% relative humidity, the dry-bulb, wet-bulb, and dew-point temperatures are equal

See relative humidity

A halocarbon that contains only fluorine, carbon, and hydrogen

Sulfate and nitrate salts to which water adheres and promotes corrosion

Formerly, the Institute of Electrical and Electronics Engineers, Inc.

A class of arithmetic, commonly used in computers. Integer arithmetic deals only in whole numbers, e.g., 1, 2, 99, 4563. Any calculation that does not result in a nice whole number is truncated back to a nice whole number and the fractional part is thrown away, e.g., 9/4 = 2 and not 2.25 or two and a quarter. Typically, computers can perform integer arithmetic more quickly than they can any other form of arithmetic, so most programs do as much work as they can in integer. However, most computers have significant limits on the values they can manage in integer format. Besides the lack of fractions, many computers cannot handle integer values beyond the millions. Thus, integers can be used to count time or to keep track of all the pennies in your bank account. However, most scientific applications deal with large values or need to be more precise than just throwing away the fractions. These kind of applications then make use of floating point arithmetic. For the SPEC CPU benchmarks, applications are classified as "integer" if they spend less than 1% of their time performing floating point calculations (which covers most non-scientific applications, e.g., compilers, utilities, simulators, etc.

See whiskers, iron

Information technology

International technology roadmap for semiconductors

Link aggregation control protocol

Link aggregation group identifier

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

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.

The transmission path between any two interfaces of generic cabling (from ISO/IEC 11801)

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)

See data center, liquid- and air-cooled

See electronics, liquid-cooled

See server, liquid-cooled

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)

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"

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

Heat release rate in units of 1000 British thermal units (BTU) per hour

The heat release in watts

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

A chip that contains a CPU. The terms microprocessor and CPU are quite often used interchangeably

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

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

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)

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.

National Fire Protection Association

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)

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)

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

Been specified by the benchmark standard

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

Occupational Safety and Health Administration

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)

Flexible cable unit or element with connector(s) used to establish connections on a patch panel (from ISO/IEC 11801: 1995)

A mechanism for full duplex flow control (see IEEE 802.3, Annex 3_1B)

A tile as part of a raised-floor system that is engineered to provide airflow from the cavity underneath the floor to the space. Tiles may be with or without volume dampers

A hand-held computer or personal organizer device

A compartment or chamber to which one or more air ducts are connected and that forms part of the air distribution system (NFPA definition)

Portability flags or changes are those which are necessary for the correct execution of a benchmark. That is, the benchmark will not run or will produce the wrong output without these flags or changes

Time rate of doing work usually expressed in horsepower or watts

The junction point between the UPS and the cabinets containing equipment

Board that contains layers of circuitry used for interconnecting the other components

A graph of the properties (temperature, relative humidity, etc.) of air. It is used to determine how these properties vary as the amount of moisture (water vapor) in the air changes

Frame for housing electronic equipment

Used to denote the total amount of electrical power being delivered to electronic equipment within a given rack. Often expressed in kilowatts (kW), this is often incorrectly equated to be the heat dissipation from the electrical components of the rack

System conditioned by removal of heat only using air

Equipment that is to be mounted in an EIA (Electronic Industry Alliance) or similar cabinet. These systems are generally specified in EIA units, such as 1U, 2U, 3U, etc., where 1U = 1.75 inches (44 mm)

Also known as access floor. Raised floors are a building system that utilizes pedestals and floor panels to create a cavity between the building floor slab and the finished floor where equipment and furnishings are located. The cavity can be used as an air distribution plenum to provide conditioned air throughout the raised floor area. The cavity can also be used for routing of power/data cabling infrastructure

The rated current is the absolute maximum current that is required by the unit from an electrical branch circuit

The supply frequency range as declared by the manufacturer expressed by its lower and upper rated frequencies

The supply voltage range as declared by the manufacturer

"N" represents the number of pieces to satisfy the normal conditions. Redundancy is often expressed compared to the baseline of "N." Some examples are "N+1," "N+2," "2N," and 2(N+1). A critical decision is whether "N" should represent just normal conditions or whether "N" includes full capacity during off-line routine maintenance. Facility redundancy can apply to an entire site (backup site), systems, or components. IT redundancy can apply to hardware and software

In a refrigerating system, the medium of heat transfer that picks up heat by evaporating at a low temperature and pressure and gives up heat on condensing at a higher temperature and pressure

A particular fire alarm control panel whose specific purpose is to monitor fire detection devices in a given area protected by a suppression system and, upon receiving alarm signals from those devices, actuate the suppression system

Reliability is a percentage value representing the probability that a piece of equipment or system will be operable throughout its mission duration. Values of 99.9 percent (three 9s) and higher are common in data and communications equipment areas. For individual components, the reliability is often determined through testing. For assemblies and systems, reliability is often the result of a mathematical evaluation based on the reliability of individual components and any redundancy or diversity that may be employed

The set of benchmark rules that defines what constitutes a valid full disclosure for that benchmark. Usually these define what parts of the benchmark configuration and the system configuration(s) that need to be detailed and disclosed

The value of the primary metric being reported for the benchmark

Return Heat Index

The point at which the equipment heat load in the room no longer allows the equipment to run within the specified temperature requirements of the equipment. The load capacity is influenced by many factors. The primary one is the room's theoretical capacity. Other factors, such as the layout of the room and load distribution, also influence the room load capacity

See exchanger, rotary heat

A layer 3 interconnection device that appears as a media access control (MAC) to a CSMA/CD collision domain (see IEEE Std 610.7-1995 [B38])

A file that contains a sequence of instructions for an interpreter or the script for that interpreter to follow

See heat load, sensible

A computer that provides some service for other computers connected to it via a network. The most common example is a file server, which has a local disk and services requests from remote clients to read and write files on that disk

An air-cooled server that accepts only room air

A contract between a network service provider and a customer that specifies, usually in measurable terms, what services the network service provider will furnish

SPEC SFS97 is the NFS server benchmark which replaced SFS93

A UNIX term for a command interpreter and its environment. Typically a program that supports the interpretation and execution of commands

Sensible heat ratio

A level of floating point accuracy that usually requires half the space for each value than does double precision, but provides considerably less precision. For most systems running the SPEC CPU tests from the OSG (e.g., CPU95), single precision implies a 32-bit value

Service level agreement

Signal-to-noise ratio

The human readable form of a computer program. This is typically the form in which the program is written, read, and modified by its human author(s)

Official name of the Gamess application of SPEChpc96, an application representative of computations used by the chemical industry

SPECjvm98 is the current Java Virtual Machine benchmark suite from SPEC

A throughput metric based on the SPEC CPU benchmarks, such as SPEC CPU95. This metric measures a system's capacity for processing jobs of a specified type in a given amount of time. The metric is used the same for multi-processor systems and for uniprocessors. It is not necessarily a measure of how fast a processor might be, but rather a measure of how much work the one or more processors can accomplish. SPECrates are one style of metric from the SPEC CPU benchmarks, the other are SPECratios

Official name of the Seismic application of SPEChpc96. It is an application representative of computations used by the seismic industry

SPECweb96 is SPEC's first attempt at a benchmark for WWW servers. It measures a server's ability to handle HTTP/1.0 GET requests from a number of external client drivers

For the OSG, the entity that has accepted the license agreement. In other words, the people who are responsible for ensuring that the results were obtained in accordance with any existing run and reporting rules. For the HPG, See benchmark sponsor who is a technical advisor for a particular benchmark

Random access memory (RAM) that retains data bits in its memory as long as power is being supplied. SRAM provides faster access to data and is typically used for a computer's cache memory

Part of the SPEC bureaucracy. Each free-standing group within SPEC has a steering committee that acts as the key decision-making body with full membership votes typically being reserved for benchmark ratifications and elections

A layer 2 interconnection device that conforms to the ISO/IEC 10038 [ANSI/IEEE 802.1D-1998]

Within IEEE 802.3, the total number of symbols per second transferred to or from the medium dependent interface (MDI) on a single wire pair. For 100BASE-T4, the symbol rate is 25 MBd. For 100BASE-X, the symbol rate is 125 MBd. For 100BASE-T2, the symbol rate is 25 MBd. For 1000BASE-T, the symbol rate is 125 MBd

Conditioned air is supplied to the inlets of the rack/cabinet 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 terminal cooling device outside of the rack is air

Time domain reflectometer

The degree or intensity of heat present in a substance or object

Temperature of air indicated by an ordinary thermometer

The entire test setup, including the SUT and any external systems used to drive, coordinate, or monitor the benchmark

Energy output as a percentage of energy input of a machine or process

An arrangement of tubes for assisting circulation in a liquid through the use of capillary action

See whiskers, tin

See heat, total

A cable element that consists of two insulated conductors twisted together in a regular fashion to form a balanced transmission line (from ISO/IEC 11801: 1995)

An electrically conducting cable, comprising one or more pairs, none of which is shielded. There may be an overall shield, in which case the cable is referred to as unshielded twisted-pair with overall shield (from ISO/IEC 11801: 1995)

Uninterruptible power supply

Typically uses batteries as an emergency power source to provide power to data communications facilities until emergency generators come on line

The vision of utility computing is to access information services in a fashion similar to those provided by telephone, cable TV, or electric utilities. It is a service provisioning model in which a service provider makes computing resources and infrastructure management available to the customer as needed and charges them for specific usage rather than a flat rate. Like other types of ondemand computing, such as grid computing, the utility model seeks to maximize the efficient use of resources and/or minimize associated costs

A material or construction that adequately impedes the transmission of water vapor under specified conditions

A system for controlling the rotational speed of either an alternating current (AC) or direct current (DC) motor by varying the voltage to the electrical power supplied to the motor

The property of a computer program, or program segment, that allows for the simultaneous execution of operations on different data values, thus making it possible to allocate the work to a set of operators and accomplish the work in parallel. One example of work that is very vectorizable is taking an entire matrix of values and multiplying each by 2. It is possible for different operators to work on different cells of the matrix at the same time. One example of work that is not vectorizable is adding to each item in an array the value of the preceding item in the array as each calculation is dependent upon the results of the preceding calculation so there is no way to perform the operations at the same time. Vectorization is only one sub-class - probably one of the most restrictive sub-classes - of parallelizable programming

The process of supplying or removing air by natural or mechanical means to or from any space. Such air may or may not have been conditioned

Refers to the delivery of air from an underfloor space, i.e., a raised-floor cavity

A self-contained operating environment that behaves as if it is a separate computer. For example, Java applets run in a Java virtual machine that has no access to the host operating system. This design has two advantages:
* System Independence: An application will run the same in any VM regardless of the hardware and software underlying the system
* Security: Because the VM has no contact with the operating system, there is little possibility of a program damaging other files or applications. The second advantage, however, has a downside. Because programs running in a VM are separate from the operating system, they cannot take advantage of special operating system features

* A configuration of a networked server that appears to clients as an independent server but is actually running on a computer that is shared by any number of other virtual servers. Each virtual server can be configured as an independent website with its own hostname, content, and security settings
* Virtual servers allow internet service providers to share one computer between multiple websites while allowing the owner of each website to use and administer the server as though they had complete control

Virtual Bridged Local Area Network (see IEEE P802.1Q)

See battery, VRLA

A period of time prior to when the actual measurement is taken, where the workload has been already started in an effort to get the SUT to a stable and consistent state

See temperature, wet-bulb

A crystalline metallurgical phenomenon whereby tin grows tiny hairs, which can become airborne under certain conditions and settle in electronic equipment

The units of work that are to be performed during a benchmark run