Legacy 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 While many of the definitions are unchanged, some of the definitions may be out of date and some of the terms may no longer be in use in the Data Center industry.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.
1 A B C D E F G H I K L M N O P R S T U V W Z

A printed circuit board with connectors where other cards are plugged. A backplane does not usually have many active components on it in contrast to a system board

Balanced Cable

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


Data traffic through a device usually measured in bits per second


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.


A document that captures the relevant physical aspects of the facility to achieve the performance requirements in support of the mission (as stated in the owner's program document)

Battery, VLA

Vented lead-acid battery

Battery, VRLA

Valve regulated lead-acid battery

Baud (Bd)

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 frame containing electronic equipment
* A space in a rack into which a piece of electronic equipment of a certain size can be physically mounted and connected to power and other input/output devices


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

Benchmark Sponsor

Every benchmark code of SPEChpc96 has a technical advisor who is knowledgeable about the code and the scientific/engineering problem, possibly with the help of experts outside the SPEC organization


Bit error ratio tester


To be specific, binary refers to a numeric representation that is comprised of (frequently very long) sequences of only two values, usually 0 and 1. Deep down at their very core, most computers really only understand 0 and 1 (or in other words, some little bit of information is either "off" or "on"). Thus, the term binary is frequently used to describe anything already translated to the form that is closest to what the system understands natively


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

Bipolar Semiconductor Technology

This technology was popular for digital applications until the CMOS semiconductor technology was developed. CMOS drew considerably less power in standby mode, and so it replaced many of the bipolar applications around the early 1990s

Bit Error Ratio (BER)

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

Bit Rate (BR)

The total number of bits per second transferred to or from the media access control (MAC). For example, 100BASE-T has a bit rate of one hundred million bits per second (108 b/s)

Blade Server

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

Blanking Panels

Panels typically placed in unallocated portions of enclosed IT equipment racks to prevent internal recirculation of air from the rear to the front of the rack


An air-moving device (also see fan)


Building management system


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)


Bit time


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

Building Automation System (BAS)

Centralized building control typically for the purpose of monitoring and controlling environment, lighting, power, security, fire/life safety, and elevators

Bus, Electrical

See bus, power

Bus, Power (or Electrical Bus)

A physical electrical interface where many devices share the same electric connection, which allows signals to be transferred between devices, allowing information or power to be shared

Bypass Air

See air, bypass