O

OAG (Open Applications Group)
An Atlanta-based, nonprofit consortium which develops standards for e-business software interoperability and integration.

OAGIS (Open Applications Group Integration Specification)
An e-business application integration standard from the Open Applications Group.

OASIS (Organization for the Advancement of Structured Information Standards)
An international nonprofit consortium that promotes open, collaborative development of e-business specifications based on public standards such as Extensible Markup Language (XML). See XML.

OBI (Open Buying on the Internet)
A standard for Internet-based procurement created by a U.S. consortium of vendors formed in October 1996, which released v.1.0 of OBI specification the following year. In 1998, the consortium placed the management of the specification under CommerceNet.

object

1. In object-oriented (OO) programming, a piece of software that contains both content and semantics describing how the content is to be interpreted or operated on. An object consists of data (attributes) and the operations (methods) that work with the data. The attributes and methods define what it means to be a particular type of object and how that object behaves. See OO.

2. In networking, any entity in a network (such as a node, printer or file server).

object class
In object-oriented (OO) programming, a grouping of objects that can be described in terms of the attributes its members have in common. For example, all of the savings accounts at a bank are instances of the class of "savings account." See OO.

Object Management Architecture (see OMA)

Object Management Group (see OMG)

object orientation, object-oriented (see OO)

object-oriented database management system (see OODBMS)

object-relational mapping
A category of tools that attempt to automate the mapping from object-oriented (OO) programming structures to relational storage structures (see OO). They are similar in intent to application integration middleware, which is designed to enable the interoperation of heterogeneous systems.

object request broker (see ORB)

object transaction monitor (see OTM)

OC-1
The base level in the Synchronous Optical Network (SONET) hierarchy of fiber-optic transmission rates. The OC-1 level represents a transmission rate of 51.84 megabits per second. See SONET and OC-N.

OC-12
A Synchronous Optical Network (SONET) telecommunications specification for fiber-optic transmission at 622 megabits per second. See SONET and OC-N.

OC-192
A Synchronous Optical Network (SONET) specification for fiber-optic transmission at an approximate rate of 10 gigabits per second. See SONET and OC-N.

OC-3
A Synchronous Optical Network (SONET) specification for fiber-optic transmission at 155 megabits per second. See SONET and OC-N.

OC-48
A Synchronous Optical Network (SONET) specification for fiber-optic transmission at an approximate rate of 2.5 gigabits per second. See SONET and OC-N.

OC-768
In the In the Synchronous Optical Network (SONET) hierarchy, transmission at approximately 40 gigabits per second. See SONET and OC-N.

OC-N (Optical Carrier Level N)
The range of incremental rates defined for Synchronous Optical Network (SONET) fiber-optic transmission (see SONET). Levels in the hierarchy are ordered by the bit rate of their aggregated signals. The number after "OC-" represents the multiple of the foundation OC-1 rate, which is 51.84 megabits per second (Mbps). Above OC-3, the level numbers and their associated data rates quadruple with each step up in the hierarchy, as follows:

• OC-3: 155 Mbps

• OC-12: 622 Mbps

• OC-48: 2.5 gigabits per second (Gbps)

• OC-192: 10 Gbps

• OC-768: 40 Gbps

OCR (optical character recognition)
The ability of a computer to recognize written characters through some optical-sensing device and pattern recognition software.

OCS (open control system)
A manufacturing system that is based on a set of commercially available, standards-based technologies, and that permits the open exchange of process data with plant systems and business systems throughout a manufacturing enterprise. "Control" refers to process control for discrete, batch and continuous-process manufacturing, as well as computer numerical control and other motion controls.

OCSP (Online Certificate Status Protocol)
A protocol used to track certificate revocation status in public-key infrastructure (PKI) security. See PKI.

OCX (OLE Custom Controls)
Visual Basic add-on components based on Microsoft's Object Linking and Embedding (OLE) set of interfaces. See OLE.

ODBC (Open Database Connectivity)
A vendor-neutral interface based on Structured Query Language (SQL) Access Group specifications. Announced by Microsoft in December 1991, ODBC accesses data in a heterogeneous environment of relational and nonrelational databases.

ODBO (OLE DB for OLAP)
A Microsoft specification for a standard interface to online analytical processing (OLAP) engines. Published in 1997, OBDO paralleled Microsoft's Open Database Connectivity (ODBC) strategy for access to relational databases. The ODBO specification was widely adopted by third-party software vendors worldwide. See OLE, OLE DB and OLAP.

ODD (optical disk drive)
A computer device that reads from, and stores information on, optical storage media. See optical disk.

ODMA (Open Document Management API)
A desktop application integration standard. ODMA provides a standard interface between document management systems and end-user applications.

ODS (operational data store)
A type of database that provides shared production data. Different from a data warehouse, the ODS is an alternative to having operational decision support system (DSS) applications access data directly from the database that supports transaction processing. The ODS tends to focus on the operational requirements of a particular business process (for example, customer service), and on the need to allow updates and propagate those updates back to the source operational system from which the data elements were obtained. The data warehouse, on the other hand, provides an architecture for decision makers to access data to perform strategic analysis, which often involves historical and cross-functional data and the need to support many applications. See data warehouse and DSS.

OECD (Organisation for Economic Co-operation and Development)
An international organization with 30 member countries "sharing a commitment to democratic government and the market economy." Originally formed under a 1960 agreement called the Convention on the Organisation for Economic Co-operation and Development, the OECD issues publications, statistics and recommendations on economic and social issues.

OEM (original equipment manufacturer)
The manufacturer of a device that another vendor resells as part of a system.

OFDM (orthogonal frequency division multiplexing)
A method of modulating broadcast data signals to minimize interference among channels that are near each other in frequency. OFDM is a type of frequency division multiplexing (FDM) often used in wireless networking. See FDM.

offline

1. Not connected to the Internet or another network— or not handled through such a connection.
2. Not under the direct control of a computer's central processing unit.

offshore
An outsourcing term describing the provision of services from a country that is geographically remote from the client enterprises — for example, services provided to a U.S. enterprise from a service provider located in India. See nearshore.

OFX (Open Financial Exchange)
A specification for bill presentment. It defines two fundamental capabilities for billing: communication of sign-up information from consolidator to biller, and communication of bill summary information from biller to consolidator. OFX does not define standards for the look of a bill. It merely provides a control channel for information about the bills.

OLAP (online analytical processing)
A category of business intelligence tools used to analyze data. OLAP tools are client- and server-based analysis tools that originally were based on multidimensional databases — databases constructed specifically to support the analysis of quantitative data, along multiple dimensions — but today can be based on relational databases, most often overlaid by an indexing or mapping scheme that emulates an MDDB. OLAP technology enables users to organize and view the data in a hierarchical manner. Most OLAP applications involve a time dimension, so that data can be analyzed over time to uncover trends. See business intelligence.

OLE (Object Linking and Embedding)
A Microsoft protocol that enables creation of compound documents with embedded links to applications, so that a user does not have to switch from one application to another to make revisions.

OLE Custom Controls (see OCX)

OLE DB (Object Linking and Embedding for Databases)
A Microsoft specification introduced in the mid-1990s as a complementary technology to Open Database Connectivity (ODBC). OLE DB was designed to provide access to multiple types of data, regardless of its location or type.

OLE DB for OLAP (see ODBO)

OLTP (online transaction processing)
A mode of processing that is characterized by short transactions recording business events, and that normally requires high availability and consistent, short response times. Unlike traditional mainframe data processing, in which data is processed only at specific times, transaction processing puts terminals online, where they can update the database instantly to reflect changes as they occur. Common applications for OLTP include systems that handle airline reservations, scheduling and inventory control.

OMA (Object Management Architecture)
An Object Management Group (OMG) architecture that defines and organizes the types of objects that provide standard services for distributed, object-oriented applications. In essence, the OMA provides a conceptual description of what distributed objects are and which infrastructure facilities are needed to support them. See OMG.

OMG (Object Management Group)
A group of member organizations (primarily vendors) set up in 1990 to foster common definitions, understanding and standards for object-oriented computing. It is best known for the Common Object Request Broker Architecture (CORBA). See CORBA.

OMS (opportunity management system)
A system tied closely to the sales process; it is the framework for any sales force automation (SFA) design. All other applications are subordinate to the OMS. Transactions flow from the OMS to other applications on the users' portable computers. Applications can be integrated among vendors. See SFA.

on-demand services
Services delivered on an as-needed, per-unit or per-seat pricing basis. On-demand services are not necessarily utility services, but IT utility services are, by necessity, on-demand ones. See IT utility services.

ONE (Open Net Environment)
Sun Microsystems' implementation of an "integratable" stack of software, hardware and services to deliver on the company's two main visions — "the network is the computer" and services on demand. Sun ONE is intended to provide a unified view of services on demand, including Sun's Java strategies and its focus on Web services.

online

1. Connected to the Internet or another network— or handled through an Internet or other network connection.
2. Under the direct control of a computer's central processing unit.

online analytical processing (see OLAP)

Online Certificate Status Protocol (see OCSP)

online service
A service that provide online access to exclusive data, information and communications resources. Customers of these services often must use proprietary software to access these resources. Many online services provide access to the Internet in addition to their exclusive resources. America Online, Microsoft Network and Lexis-Nexis are examples.

Online Service System (see OSS)

online transaction processing (see OLTP)

OO (object-oriented or object orientation)
An umbrella concept used to describe a suite of technologies that enable software to be highly modular and reusable — applications, data, networks and computing systems are treated as objects that can be mixed and matched flexibly rather than as components of a system with built-in relationships. The OO software design model is characterized by the identification of classes of objects closely linked with the methods (functions) with which they are associated; objects contain both data and the instructions that work on the data. It is a technique based on a mathematical discipline, called "abstract data types," for storing data with the procedures needed to process that data.

OOA&D (OO analysis and design)
A category of development tools that facilitate data analysis and design based on an object-oriented (OO) development approach. See OO.

OODBMS (object-oriented database management system)
A database management system (DBMS) that applies concepts of object-oriented OO programming. An OODBMS manages persistent objects on behalf of multiple users, and offers capabilities for security, integrity, recovery and contention management. See OO.

OOE (out-of-order execution)
An instruction-processing design that preserves the order of incoming and outgoing instructions, but allows up to three instructions to be processed at the same time (sometimes out of order, if there are no dependencies), speeding up total execution. This works best for single-cycle instructions rather than multicycle ones.

Open Applications Group (see OAG)

Open Applications Group Integration Specification (see OAGIS)

open architecture
A technology infrastructure with specifications that are public as opposed to proprietary. This includes officially approved standards as well as privately designed architectures for which the specifications are made public by their designers. The IBM PC, for example, was based on an open architecture, and spawned an entire industry of IBM clones.

Open Buying on the Internet (see OBI)

open control system (see OCS)

Open Database Connectivity (see ODBC)

Open Document Management API (see ODMA)

Open Financial Exchange (see OFX)

Open Group
Formed by the merger of the Open Software Foundation and X/Open in 1996, the Open Group's mission is to deliver assurance of conformance to open systems standards through the testing and certification of suppliers' products.

Open Net Environment (see ONE)

Open Shortest Path First (see OSPF)

Open Software Foundation (see OSF)

open source
Describes software that comes with permission to use, copy and distribute it, either as is or with modifications, and that may be offered either free or with a charge. The source code must be made available.

open-source software (see OSS)

open system
A system whose interfaces — for example, application programming interfaces (APIs) or protocols — conform to formal, multilateral, generally available industry standards. "Formal" implies that the standard is selected and maintained using a structured, public process. "Multilateral" implies that, while no technology is ever completely vendor-neutral, the standard is not controlled by a single vendor. "Generally available" implies that the specifications are fully published (preferably with source code of a reference implementation), and that anyone can readily obtain license rights for free or at low cost.

Open Systems Interconnection (see OSI)

OpenView
A line of Hewlett-Packard network management tools offering system, network, desktop, IT service and Internet management functionality.

Operating Resource Management System (see ORMS)

operating system (see OS)

Operating System/2 (see OS/2)

Operating System/390 (see OS/390)

Operating System/400 (see OS/400)

operational data store (see ODS)

operations support system (see OSS)

opportunity management system (see OMS)

Optical Carrier Level N (see OC-N)

optical character recognition (see OCR)

optical disk
A disk read or written using light (generally laser light). Such a disk may store video, audio or digital data.

optical disk drive (see ODD)

optical waveguide
A thin filament or planar channel made of glass or another transparent material, through which a light beam can be transmitted by means of multiple internal reflections. This enables light waves to be used to communicate data through fiber-optic cables or photonic circuits. See waveguide.

Orange Book (see TCSEC)

ORB (object request broker)
Middleware that allows objects to communicate with other software. See middleware and object.

Organisation for Economic Co-operation and Development (see OECD)

Organization for the Advancement of Structured Information Standards (see OASIS)

original equipment manufacturer (see OEM)

ORMS (Operating Resource Management System)
An Ariba e-procurement application system, introduced in 1997.

orthogonal frequency division multiplexing (see OFDM)

OS (operating system)
The main control program that runs a computer and sets the standard for running application programs. It is the first program loaded when the computer is turned on, and it resides in memory at all times. An operating system is responsible for functions such as memory allocation, managing programs and errors, and directing input and output.

OS/2 (Operating System/2)
An IBM operating system for personal computers that featured capabilities for large memory, multitasking and virtual machines.

OS/390 (Operating System/390)
IBM's premier mainframe operating system in the late 1990s. OS/390 superseded Multiple Virtual Storage (MVS), and was itself superseded by z/OS in 2000. See MVS and z/OS.

OS/400 (Operating System/400)
An IBM operating system for midrange computers.

OSF (Open Software Foundation)
A vendor consortium formed to develop multivendor standards for open systems. OSF merged with X/Open in 1996 to form the Open Group.

OSI (Open Systems Interconnection)
A model developed by the International Organization for Standardization (ISO) for communications. OSI offers a standard, modular approach to network design that divides the required set of complex functions into manageable, self-contained, functional layers. These layers, starting from the innermost, are:

1. Physical layer — concerned with the mechanical and electrical means by which devices are physically connected and data is transmitted.

2. Data link layer — concerned with how to move data reliably across the physical data link.

3. Network layer — provides the means to establish, maintain and terminate connections between systems. Concerned with switching and routing information.

4. Transport layer — concerned with end-to-end data integrity and quality of service.

5. Session layer — standardizes the task of setting up a session and terminating it. Coordinates the interaction between end application processes.

6. Presentation layer — relates to the character set and data code that is used, and to the way data is displayed on a screen or printer.

7. Application layer — concerned with the higher-level functions that support application or system activities.

OSPF (Open Shortest Path First)
An interior gateway protocol (IGP) that transfers packets from one network to an adjacent one. See IGP.

OSS (Online Service System)
An online system that offers service information, error notes and downloadable patches for R/3 and other SAP products.

OSS (open-source software)
Software that can be run, distributed and modified without a fee. Restrictions are often applied — in the form of an "open-source license" — to profits or commercial fees for any product built on a base of free software (for example, the GNU General Public License — see GNU).

OSS (operations support system)
A system that supports public-network-infrastructure operations, administration and maintenance, as well as network management functions (such as fault, configuration and security management). OSSs usually comprise software systems — residing on general-purpose or specialized computer systems — that support one or more business processes associated with network operations. Examples of the business processes addressed include planning and engineering, provisioning, performance management, and message collection and mediation.

OTM (object transaction monitor)
An application program — similar to the mainframe Customer Information Control System in function, but not in spirit — that represents a consistent model of an application for a modular and potentially highly distributed environment.

out-of-order execution (see OOE)

outsourcing
A contractual relationship with an outside vendor that is usually characterized by the transfer of assets, such as facilities, staff or hardware. It can include facilities management (for data centers or networks), application development and maintenance functions, end-user computing or business process services.

overflow

1. In telephony, excess traffic, on a particular route, that is offered to another (alternate) route.

2. In computing, a condition where data is presented to a buffer or port faster than it can be processed, resulting in lost data.

overspeed
The condition in which the transmitting device runs faster than the data can be presented for transmission.