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Windows Server 2003 Glossary - O

Updated: March 7, 2008

Applies To: Windows Server 2000, Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

For more Windows Server terms, see the Windows Server 2008 Glossary.

Glossary - O

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An entity, such as a file, folder, shared folder, printer, or Active Directory object, described by a distinct, named set of attributes. For example, the attributes of a File object include its name, location, and size; the attributes of an Active Directory User object might include the user's first name, last name, and e-mail address. For OLE and ActiveX, an object can also be any piece of information that can be linked to, or embedded into, another object.

See also: Active Directory   attribute   attribute   child object   OLE   parent object   

object access event category

In auditing, a group of events that are logged when an object, such as a file or folder, is accessed by means of an action for which auditing has been enabled. For example, object access events might be logged when a file is opened, modified, or deleted.

See also: auditing   event   object   

object class

A distinct, named set of attributes that represents a specific type of entity stored in the directory, such as users, printers, or applications. The attributes include data describing the thing that is identified by the directory object. Attributes of a user might include the user`s first name, last name, and e-mail address.

See also: directory   

object identifier

A number that identifies an object class or attribute. Object identifiers (OIDs) are organized into an industry-wide global hierarchy. An object identifier is represented as a dotted decimal string, such as, with each dot representing a new branch in the hierarchy. National registration authorities issue root object identifiers to individuals or organizations, who manage the hierarchy below their root object identifier.

See also: attribute   object class   


See other term: Open Database Connectivity (ODBC)  


A state that marks a component in a cluster as unavailable. A node in an offline state is either inactive or not running. Resources and groups also have an offline state.

See also: group   node   online   pending   resource   

offline mode

For Message Queuing, a condition in which a computer that belongs to a domain is temporarily unable to communicate with a domain controller. This occurs when the computer itself is offline, all domain controllers in the site are offline, or when an attempt is made to access a remote computer and the remote computer is temporarily unable to query a domain controller for authentication.

See also: Message Queuing   


See other term: object identifier  


A way to transfer and share information between applications by pasting information created in one application into a document created in another application, such as a spreadsheet or word processing file.

See also: embedded object   linked object   package   

on-disk catalog

Information stored on a local disk drive. The on-disk catalog contains a list of files and folders that have been backed up in a backup set.

See also: backup set   on-media catalog   

one-way trust

A trust relationship between two domains in which only one of the two domains trusts the other domain. For example, domain A trusts domain B, and domain B does not trust domain A. One-way trusts are often used to enable authenticated access to resource domains.

See also: authentication   domain   trust relationship   two-way trust   


A state that marks a component in a cluster as available. When a node is online, it is an active member of the cluster and can own and run groups as well as honor cluster database updates, contribute votes to the quorum algorithm, and maintain heartbeats. Resources and groups also have an online state.

See also: cluster   group   heartbeat   node   offline   pending   resource   

on-media catalog

Information stored on backup storage media. The on-media catalog contains a list of files and folders that have been backed up in a backup set.

See also: backup set   on-disk catalog   

Open Database Connectivity (ODBC)

An application programming interface (API) that enables database applications to access data from a variety of existing data sources.

See also: application programming interface (API)   

Open Shortest Path First (OSPF)

A routing protocol used in medium-sized and large networks. This protocol is more complex than Routing Information Protocol (RIP), but it allows better control and is more efficient in propagation of routing information.

See also: protocol   routing   Routing Information Protocol (RIP)   

Open Systems Interconnection (OSI) reference model

A networking model introduced by the International Organization for Standardization (ISO) to promote multi-vendor interoperability. OSI is a seven-layered conceptual model consisting of the application, presentation, session, transport, network, data-link, and physical layers.

See also: Transmission Control Protocol/Internet Protocol (TCP/IP)   

OpenType font

A type of computer font that can be rotated or scaled to any size. OpenType fonts are clear and readable in all sizes and can be sent to any printer or other output device that is supported by Windows.

See also: font   TrueType font   

operations master

A domain controller that has been assigned one or more special roles in an Active Directory domain. The domain controllers assigned these roles perform operations that are single-master (not permitted to occur at different places on the network at the same time). Examples of these operations include resource identifier allocation, schema modification, PDC emulation, adding and removing domains to and from the forest, and tracking changes to security principals across all domains in a forest.

See also: Active Directory   domain controller   domain naming master   infrastructure master   PDC emulator master   schema master   


In mathematics and in programming and computer applications, a symbol or other character indicating an operation that acts on one or more elements. You can use the following four operators in standard calculations: / (divide); * (multiply); - (subtract); and + (add). For Indexing Service, a word or character that specifies a relationship in a query.

See also: Indexing Service   

ordering method

The order in which targets are listed in a referral. Targets in a client’s site are always listed first in a referral (unless a target priority setting overrides this). Targets outside of a client’s site can be listed in order of lowest cost or in random order, or they can be excluded altogether from the referral.

organization claims

Claims in intermediate or normalized form within an organization's namespace.

organizational unit

An Active Directory container object used within domains. An organizational unit is a logical container into which users, groups, computers, and other organizational units are placed. It can contain objects only from its parent domain. An organizational unit is the smallest scope to which a Group Policy object (GPO) can be linked, or over which administrative authority can be delegated.

See also: Active Directory   container object   Group Policy object (GPO)   parent domain   

original equipment manufacturer (OEM)

A company that typically purchases computer components from other manufacturers, uses the components to build a personal computer, preinstalls Windows onto that computer, and then sells the computer to the public.


A member of a mirrored volume or a RAID-5 volume that has failed due to a severe cause, such as a loss of power or a complete hard-disk head failure. When this happens, the fault-tolerant driver determines that it can no longer use the orphaned member and directs all new reads and writes to the remaining members of the fault-tolerant volume.

See also: fault tolerance   mirrored volume   RAID-5 volume   

orphan file

A file that is stored inside My Briefcase and not linked to any file outside My Briefcase. When you update files, the orphan file is not synchronized with any other file.


A protected-mode, virtual memory, multitasking operating system for personal computers based on the Intel 80286, 80386, i486, and Pentium processors. OS/2 can run most MS-DOS-based programs and can read all MS-DOS disks.

See also: MS-DOS-based program   


The client-side wizard that walks a user through the installation of an operating system or provides access to maintenance and troubleshooting utilities.

See also: client   



See other term: Open Shortest Path First (OSPF)  

out-of-band connection

A connection between two computers that relies on a nonstandard network connection, such as a serial port connection, and nonstandard remote administration tools, such as Special Administration Console (SAC). An out-of-band connection is usually used only when a remote computer cannot access a network or is not in a functional state because of hardware or software failure.

See also: in-band connection   remote computer   serial port   


In a Windows environment, the person who controls how permissions are set on objects and can grant permissions to others. In the Macintosh environment, an owner is the user responsible for setting permissions for a folder on a server. A Macintosh user who creates a folder on the server automatically becomes the owner of the folder, and can then transfer ownership to someone else. Each Macintosh-accessible volume on the server also has an owner.

See also: permission   

owner category

In the Macintosh environment, the user category to which you assign permissions for the owner of a folder or a Macintosh volume.

See also: permission   volume   

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