[General] Short name for the Organization for the Advancement of Structured Information Standards (OASIS), a consortium for developing standards (e.g., KMIP).


1. [General] An instantiated instance of a class in an Object Oriented system.

2. [Data Security] In the context of access control, an entity such as an information system resource to which access is controlled and/or usage of which is restricted to authorized subjects.

3. [Data Management] The encapsulation of data and associated metadata.

object drive

[Storage System] A storage element that directly provides object services.

Object Oriented (methodology) (OO)

[General] A methodology for decomposing an entity or problem by its key abstractions, versus by its procedures or steps.

The key abstractions become classes in an information or data model, and embody well-defined behaviors called methods, with a unique set of data attributes. Instances of a class are called objects.

object service

[Storage System] Object-level access to storage.

object storage

[Storage System] A storage device that provides object services.

Object storage includes DSaaS.

Object Storage Device (OSD)

[Storage System] An object-based storage standard defined by SNIA and INCITS T10.


[Network] A data rate that is a multiple of the fundamental SONET rate of 51.84 Mbits/sec.

OC-3 (155 Mbits/sec), OC-12 (622 Mbits/sec), OC-48 (2488 Mbits/sec) and OC-192 (9953 Mbits/sec) are currently in common use. See Asynchronous Transfer Mode.


[Management] The Open Data Protocol.

OData is an OASIS standard protocol that enables the creation and consumption of RESTful APIs.

OData service

[Management] A service conforming to the OData standard.

OData allows resources, identified using Uniform Resource Locators (URLs) and defined in a model, to be published and edited by Web clients using simple HTTP messages.

offline backup

[Data Recovery] A form of backup in which the data being backed up is not accessed by applications for the duration of the backup.

offline data

[Data Management] Data that may not be accessible for an extended period of time, for example data on removable media at a remote site.

See near-online data.

offline data deduplication

[Capacity Optimization] Deprecated synonym for post-process data deduplication.


[Fibre Channel] A designation for a multimode optical fiber with a 62.5 micrometer core diameter and a bandwidth-distance product of 200 MHz*km for 850 nm optical signals.

This fiber is typical of FDDI installations. Specified by ISO 11801 second edition.


[Fibre Channel] A designation for a multimode optical fiber with a 50 micrometer core diameter and a bandwidth-distance product of 500 MHz*km for 850 nm optical signals.

This fiber is typical of 1 Gb/s Ethernet and Fibre Channel installations. Specified by ISO 11801 second edition.


[Fibre Channel] A designation for a multimode optical fiber with a 50 micrometer core diameter and a bandwidth-length product of 2000 MHz*km for 850 nm optical signals.

Optical fiber is available with considerably higher bandwidth-distance products. Specified by ISO 11801 second edition.

online backup

[Data Recovery] A form of backup in which the data being backed up may be accessed by applications during the backup.

Online backup of a set of data is usually accomplished through the use of a frozen image of the data.


[General] Acronym for Object Oriented.


1. [General] Any system or aspect of a system whose function is governed by a readily accessible standard rather than by a privately owned specification.

2. [General] Not electrically terminated, as an unplugged cable.

3. [Fibre Channel] A period of time that begins when a sequence or exchange is initiated and ends when the sequence or exchange is normally or abnormally terminated.

Open Group, the

[General] A cross-industry consortium for open systems standards and their certification.

UNIX, management and security standards are developed within the Open Group, homed at www.opengroup.org.

open interconnect

[Computer System] Synonym for standard interconnect.

operating environment

[Computer System] A collective term for the hardware architecture and operating system of a computer system.

operational (state)

[Fibre Channel] The condition of a receiver that is capable of receiving an encoded bit stream based on the rules defined by FC-FS-2 for the FC receiver state machine.

Operational Recovery (OR)

[Data Recovery] Recovery of one or more applications and associated data to correct operational problems such as a corrupt database, user error or hardware failure.

OR may use a point in time copy or other techniques that create a consistent set of recoverable data.


[Storage] Any protocol command that is delivered from a client to a storage system, including I/O operations.

See also OPS.





[Storage] Shorthand for operations per second.

This is similar to IOPS, but includes non-read and non-write operations (e.g., NFS SETATTR call, SCSI TEST UNIT READY).

OPs is also used as the plural for operations, thus, Op/s is preferred to OPs.

See also IOPS and operation.

optical fall time

[Network] The time interval required for the falling edge of an optical pulse to transition between specified percentages of the signal amplitude.

For lasers the transitions are measured between the 80% and 20% points. For LED media the specification points are 90% and 10%.

optional (characteristics)

[Standards] Characteristics of a standard that are specified by the standard but not required for compliance, but which must be implemented as defined in the standard if they are implemented at all.


[Data Recovery] Acronym for Operational Recovery.

ordered set

[Fibre Channel] A transmission word (sequence of four 10-bit code bytes) with a special character in its most significant (first on the link) position and data characters in the remaining three positions.

An ordered set is identified by the combination of special codes and data bytes that, when encoded, result in the generation of the transmission characters specified for the ordered set. Ordered sets are used for low-level Fibre Channel link functions such as frame demarcation, signaling between the ends of a link, initialization after power on, and some basic recovery actions.


1. [General] In a negotiation, the party that initiates the negotiation.

2. [Fibre Channel] With reference to an Exchange, the Nx_Port that sent the frame that caused the Exchange to become open.

Originator Exchange_Identifier (OX_ID)

[Fibre Channel] An identifier assigned by an Exchange Originator to identify an Exchange.

An OX_ID is used by both the Exchange Originator and the Exchange Responder to identify the Exchange with respect to the Exchange Originator.


[Storage System] Acronym for Object Storage Device.

out-of-band (transmission)

[Network] [Fibre Channel] Transmission of a separate data stream, such as management information, over a different medium than the primary data stream, e.g., transmission of Fibre Channel management information to a Fibre Channel component over an Ethernet network.

See in-band.

out-of-band data deduplication

[Storage System] Deprecated synonym for post-process data deduplication.

out-of-band virtualization

[Computer System] Virtualization functions or services that are not in the data path.

Examples are the management of data or storage, security management, backup of data, etc.

over provisioning

[Storage System] [Management] Purposely allocating more capacity than strictly required.

E.g., to avoid future out-of-capacity events.

E.g., in flash storage, extra capacity is reserved for controller use, is not addressable by the user, and is used to improve performance and device life.

overwrite procedure

[Data Security] A process of writing patterns of data on a magnetic medium for the purpose of obliterating data that was formerly stored there.


[Fibre Channel] Acronym for Originator Exchange_Identifier.