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 While many of the definitions are unchanged, some of the definitions may be out of date and some of the terms may no longer be in use in the Data Center industry.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

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 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


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


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"