O

OA&M

See Operations, Administration and Maintenance.

OBJECT

Encapsulated data in a compound document. For example, a single cell, a range of cells, or an entire spreadsheet could be embedded as an object in a word processing text file. Any data can be an object if it was created in a Windows application that uses OLE. Any element of information that can be manipulated by an application as a single unit. A visual component of a user interface on which an action can be performed. A type of user interface that implements the object-action paradigm of selecting an object and then selecting an action to apply to that object.

OBJECT HANDLER

A dynamic-link library for an OLE server application. This DLL acts as an intermediary between the client and server applications; for example, to improve performance when it's necessary to redraw an object in the window of the client application.

OBJECT LINKING AND EMBEDDING

(OLE) An enhancement to DDE protocol that allows you to embed or link data created in one application in a document created in another application, and subsequently edit that data in the original application without leaving the compound document. Used for transferring and sharing information between Windows-based applications. Allows users to insert multimedia elements (including video) into Windows applications.

OBS

See Optical bypass switch.

OC

Optical Carrier. See Synchronous Optical Network.

OC1

Optical Carrier, level 1 See Synchronous Optical Network.

OCNS

Orthogonal Channel Noise Source

OCTAL NUMBERING SYSTEM

A base-8 numbering system which uses only the digits 0 thru 7.

OCXO

Oven Controlled Oscillator

ODA

Office Document Architecture

ODBC

See Open Database Connectivity.

ODI

See Open Datalink Interface

OEM

An abbreviation for original equipment manufacturer.

OFF-HOOK

The condition of a telephone line that corresponds to picking up the telephone receiver. A modem creates an off-hook condition when it tries to communicate on a telephone line.

OFF-LINE TEST

In the NetWare SNA Gateway, a diagnostic test used to check for problems in the connection between the gateway and the host.

OIM

OSI Internet Management

OIW

Workshop for Implementors of OSI. Frequently called NIST OIW or the NIST Workshop, this is the North American regional forum at which OSI implementation agreements are decided. It is equivalent to EWOS in Europe and AOW in the Pacific.

OLE

See Object Linking and Imbedding.

OLTP

On-line Transaction Processing

OMNINET

Corvus Systems Inc.'s OmniNet is based on CSMA/CD running at 1Mb/s on twisted-pair cable. As with G/NET, OmniNet was not designed with large LANs in mind. In fact, only 63 nodes may exist per physical network. All nodes on an OmniNet network are cabled by patch cables that run from the main bus or trunk cable. Unlike G/NET, OmniNet patch cables can be used without reservation. In OmniNet terminology patch cables are called tap cables and they can be up to 15 feet long. Extenders are available that can be used to cable even greater distances. The tap cables are attached to tap boxes. Wires from the tap cable are terminated by an RCA jack and run back into the tap box. Inside of the box is a wire guide with wires inserted into the guide from the trunk cable. This combination is free-standing and vulnerable to contamination from oxidation. To provide better operation from the tap box to the trunk cable, it is highly recommended that the installer solder the connections on these wire guides. This alone can remedy some of the network performance problems associated with OmniNet. Note that as with G/NET, OmniNet is available from only one vendor.

OMPAC

See OverMolded Pad Array Carrier.

ON-HOOK

The condition of a telephone line that corresponds to hanging up the telephone receiver. A modem creates an on-hook condition to break its connection to a telephone line.

ON-LINE MODE

One of the two operating modes of the modem, also called data mode. (See Command Mode.) In on-line mode, the modem interprets all information sent to it as data, not commands. The only exception is the escape sequence (normally +++), which returns the modem to command mode without breaking the connection. The modem is placed in on-line mode when it makes a connection with a remote modem, or when you enter the O command to return to a previously established connection.

ONC(TM)

See Open Network Computing.

OP

IC part number prefix indicating Precision Monolithics, Inc.

OPEN DATABASE CONNECTIVITY

Microsoft's strategic interface for accessing data in a heterogeneous environment of relational and non-relational database management systems. Allows differing database programs to share a common data format. An open, vendor neutral system. Each application uses the same code, as defined by the API specification, to talk to many types of data sources through DBMS-specific drivers. A driver manager sits between the applications and the drivers. In Windows, the Driver Manager and the drivers are implemented as DLLs. The application calls ODBC functions to connect to a data source, send and receive data, and disconnect.

OPEN DATALINK INTERFACE

(ODI) A data-link specification jointly developed by Apple Computer and Novell and published to the networking industry in 1989. The strategic goal of ODI is to provide seamless network integration at the transport, network, and data-link levels. ODI simplifies the development of network drivers for a wide variety of network adapters and network transport protocol stacks. The result is easier access to a wide variety of networked resources without requiring multiple network connections or additional investments in hardware and software. ODI's architecture is designed to radically simplify support for multiple protocols on a single network. Rather than installing a separate driver and adapter for each client type that needs to be supported on the network, ODI consolidates the support for multiple protocols under one driver. This means that one adapter in the server can support various clients on the network. ODI provides transport support so a Apple Macintosh (using the AFP protocol) can use a NetWare server to queue and print documents and save data files that are shareable with other types of workstations. UNIX, OS/2, TCP/IP and other clients can be supported in a similar manner. ODI allows a network to support many different protocols (such as IPX/SPX, TCP/IP and AppleTalk) with ease. ODI also allows network managers to integrate new protocols (or enhancements to existing protocols) into existing networks as they become available. ODI consolidates services on the client side as well. Using the right ODI adapter/driver combination, a workstation can access services from a NetWare server and a UNIX host without rebooting the client. And only one client card is needed to support both IPX and TCP/IP. Thus, ODI allows for multiple types of workstations to communicate transparently with network services through a single server. Furthermore, ODI lets a single protocol stack communicate with multiple LAN cards, (for example, an IPX router) which was not previously possible with Dedicated IPX. ODI drivers are also much easier to install and upgrade than Dedicated IPX drivers: under Dedicated IPX the driver had to be bound to the operating system through NETGEN or SHGEN. If a customer wanted to upgrade the driver, he or she had to re-install (re-gen) the operating system. This can be a time consuming process, especially when considering that the operating system must be re-installed exactly as it was set up before-whoever does the installation has to know all of the defaults and settings that were set on the original file system, otherwise the system won't be completly functional when it is re-intalled. ODI alleviates this problem entirely by allowing new and updated drivers to be loaded on the fly. Simply unload the existing driver and load the new one, and the underlying file system remains uneffected. ODI has many advantages over Dedicated IPX.

OPEN NETWORK COMPUTING

A distributed applications architecture promoted and controlled by a consortium led by Sun Microsystems.

OPEN SHORTEST PATH FIRST

(OSPF) A link state Interior GW Protocol uses between routers to exchange routing information.

OPEN SOFTWARE FOUNDATION

(OSF) A consortium of computing industry vendors organized to develop an open, UNIX-based operating system standard. OSF's first operating system release, called OSF/1, is built on the IBM UNIX-based AIX kernel and the Motif graphical user interface.

OPEN SYSTEM

A system that implements enough open specifications for interfaces, services, and supporting formats to enable properly engineered applications software to port with minimal changes across a wide variety of systems, to interoperate with other applications on local and remote systems, and to interact with users so as to facilitate portability.

OPEN SYSTEMS INTERCONNECT

(OSI) 7-layer Model (OSI Model) A model developed by International Standards Organization to establish a standardized set of protocols for interoperability between networked computer hosts. Each layer of the model consists of specifications and/or protocols that fulfill specific functions in a networking architecture. The OSI Model parallels DECnet, SNA, XNS, and other networking models. Novell's UNA was patterned against the OSI Model. The OSI Model consists of specific protocols that are nonproprietary and offered in the hope of unifying networking protocols used in competing vendors' systems. An ISO publication that defines seven independent layers of communication protocols. Each layer enhances the communication services of the layer just below it and shields the layer above it from the implementation details of the lower layer. In theory, this allows communication systems to be built from independently developed layers. Open Systems Interconnection model - Not a specific protocol format - breaks data communications into 7 layers:

Layer 1 is hardware based but not the physical communication media. Layers 2 to 7 are software based.

1 = physical

2 = data link

3 = network

4 = transport

5 = session

6 = presentation

7 = application

OPEN SYSTEMS INTERCONNECTION REFERENCE MODEL

The architecture developed by the ISO to standardize networking and data communications. The OSI model has seven layers: the physical, data link, network, transport, session, presentation, and application layers. The OSI model is frequently used for microcomputer networks, and the SNA model, for IBM host computer networks.

OPERATING SYSTEM

The software that governs the operation of a computer, providing services such as resource allocation, scheduling, input/output control, and data management. Popular operating systems include MS-DOS and UNIX.

OPERATIONS, ADMINISTRATION AND MAINTENANCE

(OA&M) A module that provides the maintenance and administration interface.

OPTICAL BYPASS SWITCH

(OBS) An optional switching function that controls whether or not to bypass a ring when the FDDI interface card is down or removed.

OPTICAL CARRIER

See Synchronous Optical Network.

ORIGINATE MODE

The mode used by the modem when calling another computer. See also Answer Mode.

OS/2 REQUESTER

NetWare workstation software that links an OS/2-based workstation to a NetWare server. The OS/2 Requester loads IPX and NIC drivers as SYS files during loading. The OS/2 Requester hears OS/2 and application function calls and echoes them to the server in the form of NCP function calls in the packet header. This software is the OS/2 workstation equivalent of the DOS shell. See Shell, NCP, and OSI model.

OSF

See Open-Software Foundation.

OSI

See Open-systems Interconnect.

OSI MODEL

See Open Systems Interconnection Reference Model.

OSI NETWORK ADDRESS

The address, consisting of up to 20 octets, used to locate an OSI Transport entity. The address is formatted into an Initial Domain Part which is standardized for each of several addressing domains, and a Domain Specific Part which is the responsibility of the addressing authority for that domain.

OSI PRESENTATION ADDRESS

The address used to locate an OSI Application entity. It consists of an OSI Network Address and up to three selectors, one each for use by the Transport, Session, and Presentation entities.

OSPF

See Open Shortest Path First.

OTDR

Device that located faults in optical fibers or infers attenuation from backscattered light measurements.

OTOH

On the other hand

OVERLAY

The ability to superimpose computer graphics over a live or recorded video signal and store the resulting video image on videotape. It is often used to add titles to videotape.

OVERLAY INFECTION

Virus contamination of a file containing auxiliary program code that is loaded by the main program.

OVERMOLDED PAD ARRAY CARRIER

(OMPAC) Motorola's trademark for PBGA.

OVI

Open Verilog International (Logic simulation acronym)