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 While many of the definitions are unchanged, some of the definitions may be out of date and some of the terms may no longer be in use in the Data Center industry.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

Link aggregation control protocol


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


Link aggregation group identifier

Latent Heat Load

See heat load, latent

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


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


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 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


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)

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)