Microsoft Visual Tools Glossary

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Activate Also Activation A programming process which loads an object into memory, putting the object into an executable or running state. Also, the process of binding an object so as to put the object into its running state. Also, invoking a particular operation, such as setting a method or property, on an object. See also Bind and Object.

Active Client The Active Client is the client-side element of the Active Platform that enables cross-platform content and applications. Active Client technology is available for key commercial computing operating systems including Windows® 95, Windows NT®, Apple Macintosh, and UNIX. It includes support for HTML, scripting (VBScript and JScript), Java applets, ActiveX™ Components, ActiveX Controls and Active Documents.

Active Document A Windows-based, non-HTML application embedded in a browser, providing a way for the functionality of these applications to be accessible from within the browser interface.

Active Group, The A standards organization, under the auspices of The Open Group, which is an open, customer-driven steering committee responsible for the ongoing development and management of ActiveX technologies and licensing. You can read more by visiting the Web site at

Many links on this page point to servers that are not under the control of Microsoft Corporation. Please read our disclaimer before continuing.

Active Platform An integrated, comprehensive set of client--Active Client--and server--Active Server--component-based development technologies that make it easy for developers to integrate the connectivity of the Internet with the power of the personal computer. The Active Platform is an open platform developers can use to take full advantage of Microsoft's leading, standards-based implementations of HTML, open scripting, component architecture and underlying operating system services.

Active Server The Active Server is the server-side element of the Active Platform, specifically, a collection of server-side technologies that are delivered with Windows NT, and provide a consistent server-side component and scripting model, and an integrated set of system services, for component application management, database access, transactions, and messaging.

Active Server Page The server-side execution environment (formerly code-named "Denali") in Microsoft Internet Information Server 3.0 that executes ActiveX Scripts and ActiveX Components on a server. Developers can combine scripts and components to create Web-based applications.

ActiveX A set of language-independent interoperability technologies that enable software components written in different languages to work together in networked environments. The core technology elements of ActiveX are COM and DCOM. These technologies are licensed to the Open Group standards organization, and are being implemented on multiple platforms.

ActiveX Automation A language-neutral way to manipulate an ActiveX Component's methods from outside an application. ActiveX Automation is typically used to create components that expose methods to programming tools and macro languages. ActiveX Automation was previously called OLE Automation. For more information about ActiveX Automation, you can refer to OLE Programmer's Reference, Volume 2, which is available from the Microsoft Press® Online Book store: .

ActiveX Control A compiled software component based on the component object model (COM) that encapsulates a set of business or user interface functions. An ActiveX Control is used to provide user interface components and is designed to run on the client computer. These were formerly called OLE Controls. Optimizations in the technology resulted in smaller, faster software components and support for key features used to distribute components 'just in time' over networks such as the Internet. ActiveX Controls can be embedded in Web pages for use over the Internet as well as combined to create client/server applications that run over a corporate network. They can be created by a variety of programming languages from Microsoft or from third-party vendors. ActiveX Controls use the file extension .ocx. See also COM, Controls, and Events.

ActiveX Component A compiled software component based on the component object model (COM) that encapsulates a set of business functionality. The functionality in an ActiveX component is accessed through ActiveX Automation interfaces. The ActiveX Component can execute either on a client computer or on a server computer, transparent to the calling application, through DCOM. ActiveX Components can be driven by a scripting language such as VBScript or JScript. All Java applets, running in the Microsoft virtual machine for Java, are automatically ActiveX Components and use the file extension .class. ActiveX Components that run within the calling application process use the file extensions .dll or .ocx. ActiveX Components that run outside of the calling application process use the file extension .exe. See also COM.

ActiveX Server Component An ActiveX Component designed to run on the server-side of a client/server application. See ActiveX Component.

ActiveX Scripting The act of using a scripting language to drive ActiveX Components. ActiveX Scripting is made possible by plugging a scripting engine into a host application. A scripting engine enables the processing of a specific scripting language such as VBScript or JScript. Examples of host applications that contain scripting engines are Microsoft Internet Explorer and Internet Information Server with Active Server Pages. See Active Server Pages, ActiveX Automation, ActiveX Components, and Script.

ADO Active Data Objects. A set of object-based data access interfaces optimized for Internet-based, data-centric applications. ADO is based on a published specification and ships with Microsoft Internet Information Server and Microsoft Visual InterDev™.

Aggregation A programming composition technique for implementing component objects. Using this technique, developers can build a new object using one or more existing objects that support some or all of the new object's required interfaces.

Anonymous FTP Anonymous File Transfer Protocol. Used in the process of connecting to a remote computer as an anonymous or guest user in order to transfer public files to your local computer. See also FTP.

ANSI American National Standards Institute. ANSI serves as a quasi-national standards organization. It provides area charters for groups that establish standards in specific fields, such as the Institute of Electrical and Electronics Engineers (IEEE). Also, commonly used to refer to a low-level table of codes used by a computer. Most computers can choose among several different software code tables for deciding how to display information on a screen and how keys pressed on a keyboard appear as characters on a computer screen or printer.

Apartment Model Multi-threading The Component Object Model (COM) supports a form of multi-threading in Windows 95 and Windows NT called the apartment model. Apartment is essentially a way of describing a thread with a message queue that supports COM objects. Apartment model multi-threading enables multiple application threads--one for each apartment--that are managed by COM.

APE Application Performance Explorer. A software utility written in Microsoft Visual Basic® to aid in the design, deployment planning, and performance tuning of distributed client/server applications. A download copy is available on the Web site at

API Application Programming Interface. A set of routines that an application program uses to request and carry out lower-level services performed by a computer's operating system. Also, a set of calling conventions in programming that define how a service is invoked through the application.

Applet An HTML-based program built with Java that a browser temporarily downloads to a user's hard disk, from which location it runs when the Web page is open.

Asynchronous Call A function that enables processing to continue without waiting for the function to return a value.

ATM Asynchronous Transfer Mode. A communications protocol defined for high-speed data communications.

Automation See ActiveX Automation.


Bandwidth The capacity of the transmission medium stated in bits per second (bps) or as a frequency (Hz). Generally, a higher bandwidth number indicates faster data-transfer capability.

Baud Roughly the speed at which a modem transfers data. One baud is approximately equal to one bps, although baud rate and bps are not always synonymous. Bps is usually a more accurate measure of modem speed.

BBS Bulletin Board System. A shared file system where users can enter or post information for other users to read or download. Many bulletin boards are set up according to a particular topic of interest.

Bind To put an object into its running state, allowing the operations it supports to be invoked. Also Binding. Objects can be bound at run time--called late binding or dynamic binding--or at compile time--called static binding.

Bit A binary digit, the basic unit of computer storage. A bit may have a value of either zero or one. All computer information is ultimately represented as bits in computer storage, whether the storage is disk storage or memory storage.

BLOB Binary Large Object. A generic term used to describe the handling and storage of long strings of data by database management systems. Typically associated with image and video.

BPS Bits Per Second. The speed at which data bits are transmitted over a communications medium, such as a transmission wire or a modem. Common PC modem speeds are 28,800 and 14,400 bps.

Browser A program that interprets hypertext markup language (HTML) and displays information on a computer screen. Using a browser, a person can read hypertext and view graphical images. A person uses a browser to view the contents of network nodes and to navigate among nodes. Popular examples include Microsoft Internet Explorer and Netscape Navigator.

Byte Code The executable form of Java code that executes within the Java Virtual Machine. Also called interpreted code, pseudocode, or p-code.


Cache Usually a temporary local store for information, a special memory subsystem where frequently used data values are copied and stored for quick access.

Call To transfer program execution to some other section of code, usually a subroutine, while saving the necessary information to allow execution to resume at the calling point when the called section has completed execution.

CASE Computer Aided Software Engineering. Software that aids in application development including analysis, design, and code generation. CASE tools provide automated methods for designing and documenting traditional-structure programming techniques.

CGI Common Gateway Interface. A server-side interface for initiating software services. A set of interfaces that describe how a Web server communicates with software on the same computer. Any software can be a CGI program if it handles input and output according to the CGI standard. See also Gateway and Server.

Class A generalized category in object-oriented programming that describes a group of more specific items called objects. A class provides a template for defining the behavior of a particular type of object. Objects of a given class are identical to each other in form and behavior. A class is a descriptive tool used in a program to define a set of attributes or services that characterize any member (object) of the class. Program classes are comparable in concept to how people organize information--one familiar example being the categories animal, vegetable, and mineral, which define elements of the physical world.

Class Identifier A unique identification tag (UUID) associated with a class object. Also CLSID. A class object that is intended to create more than one object registers its CLSID in a task table in the system registration database to enable clients to locate and load the executable code associated with the object(s). Every application that uses COM objects --or any container that allows linking to its embedded objects--must register a CLSID for each supported object definition.

Class Library A collection of one or more classes that programmers use to implement functionality.

Class Object A member object within a class.

Client A program that facilitates a connection to server computers and manages and presents information retrieved from those sources. In a client/server environment, the workstation is usually the client computer. In referring to COM objects, an object that requests services from another object. See also Container Application.

Client/Server A model of computing whereby client applications running on a desktop or personal computer access information on remote servers or host computers. The client portion of the application is typically optimized for user interaction, whereas the server portion provides the centralized, multi-user functionality.

COM Component Object Model. The object-oriented programming model that defines how objects interact within a single application or between applications. In COM, client software accesses an object through a pointer to an interface--a related set of functions called methods-- on the object.

Communications Protocol A set of rules or standards designed to enable computers to connect with one another and to exchange information with as few errors as possible. Some communication protocols contain other protocols, such as hardware protocols and file transfer protocols. Examples include HTTP, TCP/IP, and SNA.

Component See ActiveX Component.

Compound Document A document that contains data in different formats created by different applications. Compound documents are created in a container application, such as Microsoft Word, and information from another application, such as a spreadsheet from Microsoft Excel, a sound clip, or a bitmap, is either embedded in or linked to the container application.

Container Application An application that supports compound documents or components. A container application provides storage for the embedded object, a site for display, access to the display site, and an advisory sink for receiving notification of changes in the object. Microsoft Word and Microsoft Internet Explorer are both examples of a container application.

Control In a graphical user interface, an object on the screen that can be manipulated by a user to perform an action. Perhaps the most common controls are buttons that a user can click to select an option, and scroll bars that a user employs to move through a document or position text in a window. See also ActiveX Control.

Cookies A means by which, under the HTTP protocol, a server or a script can maintain state or status information on the client workstation. Said another way, a cookie is bits of information about person's visit to a Web page. A cookie can include such information as the way a Web page was customized, how a visitor shopped on a Web site, or to track repeat visits.

CORBA Common Object Request Broker Architecture. An Object Management Group specification for the interface definition between OMG-compliant objects.

Cursor Engine A mechanism for managing data retrieved from a database, or a full transaction manager that optimizes the retrieval and update of server-based data.


DAO Data Access Objects. Programming interfaces used by an application developer. DAO includes the full functionality of the Microsoft Jet database engine for local data management, and ODBC version 3.5 includes ODBC Direct for fast access to remote data. See also Jet and ODBC.

Data Dictionary A repository of information about data, such as its meaning, relationships to other data, origin, usage, and format. A data dictionary manages data categories such as alias, data elements, data records, data structures, data stores, data models, data flows, data relationships, processes, functions, dynamics, sizes, frequencies, resource consumption, and other user-defined attributes of data.

DCE Distributed Computing Environment. An open set of services controlled by the OSF and designed to support performing distributed computing across heterogeneous platforms.

DCOM Distributed Component Object Model. Additions to the Component Object Model (COM) that facilitate the transparent distribution of objects over networks and over the Internet. DCOM is part of the specification managed by The Open Group for deployment across heterogeneous platforms. See also COM and The Open Group.

Debugger A development environment that supports step-by-step execution of application code and viewing the content of code variables.

Design-time ActiveX Controls Visual authoring components that help a developer construct dynamic Web applications by automatically generating standard HTML and/or scripting code. They are analogous to wizards. Design-time ActiveX Controls exist at design time, and not at run time.

DHCP Dynamic Host Configuration Protocol. A TCP/IP protocol that assigns Internet protocol addresses to stations in a network. The DHCP-server computer makes the assignments, and the client computer calls the server computer to obtain the address.

Directory Services Middleware that locates the correct and full network address from a partial name or address typed into a dialog box.

Distributed Processing The physical or logical distribution of software components, processing, data, and management of application software.

DLL Dynamic Link Library. A feature of the Microsoft Windows family of operating systems that supports executable routines--usually serving a specific function or set of functions--to be stored separately as files with the extension .dll, and to be loaded only when called by the program that needs them. This saves memory during program execution and enables code reusability.

DNS Domain Name Service. A protocol that provides an Internet-wide database of host and domain names. For example, DNS is used to find the IP address of a host name written as Reverse DNS is used to find the host name given an IP address.

Domain Name An entry in an Internet address, such as in the fictitious U.S. address In the United States, common domain names end with .com (for commercial organizations), .org (for organizations), .net (for network providers), .gov (for government), and .mil (for military). In other countries, two-letter codes represent each country, for example: .fr for France, .de for Germany, .uk for the United Kingdom, .ca for Canada, and .jp for Japan.

DSOM Distributed System Object Model. IBM's distributed object technology, which originated with the IBM operating system named OS/2 version 2.0 and the UNIX operating system, AIX (Advanced Interactive eXecutive). DSOM is a follow on to System Object Model (SOM), although it uses a separate object model.


ECMA European Computer Manufacturers Association. A standards organization, based in Switzerland, composed of computer vendors and business-equipment manufacturers and suppliers. This association is concerned with the development of standards for data processing and business equipment.

E-commerce Electronic Commerce. The process of buying and selling over the Web--often based on software products such as the Microsoft Merchant Server.

Electronic Bulletin Board System See BBS.

E-mail-enabled Applications Business applications that use an e-mail infrastructure to manage the store-and-forward function associated with controlling workflow and user notification.

Event Any action, often generated by a user or an ActiveX Control, to which a program might respond. Typical events include pressing a keyboard key, choosing a button using a mouse click, and other mouse actions. Programmers write code to respond to these actions.

Executable Program A computer program that is ready to run. For example, a word processing program that a user does not have to alter before using it to create documents. Also, Executable Code and Executable Routine.


FAQ Frequently Asked Questions. Usually a document containing questions and answers that address the basics. A visitor can find an FAQ on most every Web site. A FAQ serves to introduce a visitor to the topic or subject of the Web site and to offer general guidelines about how to best use the site.

FDDI Fiber Distributed Data Interface. An emerging standard for network data transfer based on fiber optic technology, established by the American National Standards Institute (ANSI). FDDI specifies a 100-million bit per second (Mbps) data rate. The access control mechanism for this interface uses token ring--a network formed in a close loop (ring)--technology.

File Server A computer containing disk files available to all users connected to a local-area network (LAN). In some LANs, a microcomputer is designated as the file server, while in others it is a computer with a large disk drive and specialized software. Some file servers also offer other resources, such as a gateway and protocol conversion.

Firewall A security mechanism--such as the Microsoft Proxy Server--that provides Internet access from desktops inside an organization, while at the same time preventing access to the corporate LAN by outside Internet users. See also Proxy Server.

FTP File Transfer Protocol. The Internet standard high-speed protocol for downloading or transferring files from one computer to another. Usually files transferred using this protocol are larger or take many minutes, sometimes hours, to transfer.

Function A general term used for a subroutine. In some programming languages, a subroutine or statement that returns values.


Gateway Conversion software that integrates dissimilar entities such as network protocols, software object models, or data storage devices.

GIF Graphics Interchange Format. A computer graphics file format developed in the mid-1980s by CompuServe for use in photo-quality graphic image display on computer screens. Now commonly used most everywhere on the Internet.

Gopher An early Internet protocol and software program designed to search for, retrieve, and display documents from remote computers or sites. Gopher clients are used to connect to remote Gopher servers. Interaction is typically carried out through a menu hierarchy. Gopher was created by a development team at the University of Minnesota and is named after that school's mascot.

GUI Graphical User Interface. A user interface that displays graphics and characters and which provides an event model for users to control the operating environment.

GUID Globally Unique Identifier. Identifiers (IDs) assigned to COM objects that are generated through a sophisticated algorithm. The algorithm guarantees that all COM objects are assigned unique IDs, avoiding any possibility of a naming conflict, even in distributed systems with millions of objects supplied by different vendors.


H.263 ITU standard for low bit-rate for video encoding. Used as a basis for video conferencing over the Internet.

H.320, H.323, H.324 A set of protocols from ITU for audio, video, and data conferencing that integrates with T.120 over ISDN, TCP/IP--including RTP/RTCP, and analog phone lines--POTS or plain old telephone service--respectively.

Home Page The page that serves as the starting point of a World Wide Web site, sometimes named default.html or index.html.

Host Any computer that provides services to remote computers or users.

Hot Link A connection to a document or other file on the Internet that generally appears as a highlighted word or image on the screen. Also Hypertext Link or Link.

HTML Hypertext Markup Language. A tag-based notation language used to format documents that can then be interpreted and rendered by an Internet browser, usually on the World Wide Web, but that can also be rendered on a local computer or internal network by a browser.

HTTP Hypertext Transfer Protocol. A basic communication protocol for Internet or Web server file input and output (I/O).

Hypertext A hypertext document is a document structured in chunks of text and marked up usually using HTML, which is connected by links. Hence, the text in the document can properly be named hypertext because of its marked-up and navigable condition.


IDC Internet Database Connector. IDC is a core component of the Microsoft Internet Information Server (IIS). It provides database connectivity between IIS applications and any ODBC-compliant database.

IEEE Institute of Electrical and Electronic Engineers. The professional organization of engineers that reviews current information in the fields of electrical engineering and electronics. Members represent an international cross-section of users, vendors, and engineering professionals. The IEEE develops standards on definitions, test methods, symbols, units, and safety in the field of electrical science and engineering.

IETF Internet Engineering Task Force. A protocol engineering and development organization focused on the Internet. The IETF is a large, open international community of network designers, operators, vendors, and researchers concerned with the evolution of the Internet architecture and the smooth operation of the Internet. It is now under the auspices of the Internet Society, a non-governmental international organization for global cooperation and coordination for the Internet and its inter-networking technologies and applications.

IIS Microsoft Internet Information Server.

Inheritance A programming technique that duplicates the characteristics down a hierarchy from one class to another.

In-process Server An ActiveX Component that shares the same memory as the container application.

Instance An object for which memory is allocated or persistent.

Instantiate To create an instance of an object. The process of creating or activating an object based on its class.

Interface The point at which a connection is made between two elements so they can work with one another. In computing, different types of interfaces occur on different levels, ranging from highly visible user interfaces to often invisible yet necessary interfaces that connect devices and components. A developer activates an interface using programming language commands.

Also, a group of related functions that provide access to COM objects. The set of interfaces defines a contract that allows objects to interact according to the Component Object Model (COM).

Internet Abbreviation for Internetwork. A set of dissimilar computer networks joined together by means of gateways that handle data transfer and the conversion of messages from the sending network to the protocols used by the receiving networks. These networks and gateways use the TCP/IP suite of protocols. Originally part of the Department of Defense's Advanced Research Project Administration (DARPA).

Intranet Use of Internet standards, technologies, and products within an enterprise to function as a collaborative processing infrastructure. The term intranet is generally used to describe the application of Internet technologies on internal corporate networks.

IP Internet Protocol. The packet-switching protocol for network communications between Internet host computers.

ISAM Indexed Sequential Access Method. An indexing mechanism for efficient access to rows of data in a file.

ISAPI Internet Server Application Program Interface. An application program interface that resides on a server computer for initiating software services tuned for Microsoft Windows NT operating system.

ISDN Integrated Services Digital Network. An emerging technology that is beginning to be offered by most telephone service providers as a faster alternative to traditional modems. ISDN combines voice and digital network services in a single medium, making it possible to offer telephone customers digital data service and voice connection through a single "wire."

ISO International Standards Organization. An international standards organization involved in setting standards worldwide for all fields except electro-technical, which is the responsibility of IEC. ISO carries out its work thorough a range of working groups.

ISP Internet Service Provider. An organization that provides access to the Internet.

ISV Independent Software Vendor.

ITU International Telecommunication Union.


Java A derivative of the C++ language, Java is SunSoft's distributed programming language, offered as an open standard.

JavaScript A scripting language that evolved from Netscape's LiveScript language and was made more compatible with Java. It uses an HTML page as its interface. See also JScript.

Java Beans An object model being developed by SunSoft that is targeted to inter-operate with a variety of other object models, including COM and CORBA.

JDBC Java Database Connectivity. Data access interfaces based on ODBC for use with the Java language.

Jet A Microsoft desktop database engine available in most of Microsoft's development tools and office products, including Microsoft Access, Microsoft Office, and Microsoft Visual Basic.

JPEG Joint Photographic Experts Group. A widely accepted international standard for compression of color image files, sometimes used on the Internet.

JScript The Microsoft open implementation of JavaScript. JScript is fully compatible with JavaScript in Netscape Navigator version 2.0.


Kerberos The basis of most of the distributed computing environment (DCE) security services. Kerberos provides the secure use of distributed software components.


Latency The state of being latent, or to lie hidden; not currently showing signs of existence. Sometimes attributed to the time taken to retrieve pages from the World Wide Web .

LAN Local Area Network. A connection among a set of computers. Computers connected to a LAN can generally share applications or files from a local file server and may be able to connect to other LANs or to the Internet using routers.

LDAP Lightweight Directory Access Protocol. An open standard protocol (RFC 1777) that provides a way for Internet clients, applications, and servers to access directory services. LDAP was derived from the DAP X.500 protocol.

Link See Hot Link.


MAPI Mail or Messaging Applications Programming Interface. An open and comprehensive messaging interface used by programmers to create messaging and workgroup applications--such as electronic mail, scheduling, calendaring, and document management. In a distributed client/server environment, MAPI provides enterprise messaging services within WOSA.

Marshal The process of packaging and sending interface parameters across process boundaries in computer memory. Also Marshalling.

Message Queuing Server technology developers can use to build large-scale distributed systems with reliable communications between applications that can continue to operate reliably even when networked systems are unavailable. This technology is being developed in the Microsoft project code-named "Falcon."

Method Member functions of an exposed object that perform some action on an object, such as saving it to disk. A method is a logical operation provided by an object. Operations performed on objects are defined as methods of the object. To invoke a method, an object sends a message consisting of the receiving object and the name of the specific method to invoke. The name of the method is sometimes called a selector. Messages are the mechanism through which objects interact.

Middleware The network-aware system software, layered between an application, the operating system, and the network transport layers, whose purpose is to facilitate some aspect of cooperative processing. Examples of middleware include directory services, message-passing mechanisms, distributed TP monitors, object request brokers, remote procedure call (RPC) services, and database gateways.

MIME Multipurpose Internet Mail Extensions. An extension of the Internet mail protocol that enables sending 8-bit based e-mail messages, which are used to support extended character sets, voice mail, facsimile images, and so forth.

Moniker A name that uniquely identifies a COM object similar to a directory path name. Monikers support an operation known as binding, which is the process of locating the object named by the moniker, activating it or loading it in memory if it isn't already there, and returning an interface pointer to it.

MPPP Multi-link Point-to-Point Protocol. This is a standard communications protocol used over ISDN to join separate B channels to transfer data effectively through a larger pipeline. MPPP allows both channels to be used for either voice or data transmissions.

MTS Microsoft Transaction Server. Formerly code-named "Viper," MTS is a new product that combines the features of a transaction-processing (TP) monitor and an object-request broker (ORB) in an easy-to-use product.

Multi-tasking The ability to simultaneously execute multiple applications within an operating system.

Multi-tier Architecture Also known as three-tier, multi-tier is a technique for building applications generally split into user, business, and data services tiers. These applications are built of component services that are based on an object model such as ActiveX.

Multi-threading Running several processes in rapid sequence within a single program, regardless of which logical method of multi-tasking is being used by the operating system. Because the user's sense of time is much slower that the processing speed of a computer, the impression of multi-tasking appears simultaneous, even though only one task at a time can use a computer processing cycle.


NIST National Institute of Standards and Technology. The division of the U.S. Department of Commerce that ensures standardization within government agencies. NIST was formerly known as the National Bureau of Standards (NBS).

NNTP Network News Transport Protocol. A news service protocol that is an extension of the TCP/IP local area network protocol. NNTP is the standard for Internet exchange of Usenet messages, published in RFC-977.

Node A computer that is attached to a network; also called a host. Also, a junction of some kind. On a local area network, a device that is connected to the network and is capable of communicating with other network devices.


Object In object-oriented programming, a variable comprising both routines and data that is treated as a discrete entity. An object is based on a specific model, where a client using an object's services gains access to the object's data through an interface consisting of a set of methods or related functions. The client can then call these methods to perform desired operations.

Object Orientation Representing the latest approach to accurately model the real world in computer applications, object orientation is an umbrella concept used to describe a suite of technologies that enable software products that are 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. As a result, an application need not be tied to a specific system or data to a specific application. The four central object-oriented concepts are encapsulation, message passing, inheritance, and late binding.

OCX File extension for an ActiveX Control or ActiveX Component. Originally used as a file extension for OLE Custom Controls, following the format for a Visual Basic Extension (VBX).

ODBC Open Database Connectivity. A vendor-neutral interface, based on the SQL Access Group specifications, announced by Microsoft in December 1991. A developer can use ODBC to access data in a heterogeneous environment of relational and non-relational databases.

ODBCDirect Technology that makes the full functionality of RDO available from within DAO. Used to bypass the Microsoft Jet database engine for fast, small-memory-footprint access to remote data. See also DAO, Jet, and RDO

OLAP Online Analytical Processing. A multi-dimensional database used for decision support analysis and data warehousing.

OLE Object Linking and Embedding. A set of integration standards to transfer and share information among client applications. A protocol that enables creation of compound documents with embedded links to applications so that a user does not have to switch among applications in order to make revisions. OLE is based on the Component Object Model (COM) and allows for the development of reusable, plug-and-play objects that are interoperable across multiple applications. This has been broadly used in business, where spreadsheets, word processors, financial packages, and other PC applications can share and link disparate information across client/server architectures.

OLE Automation See ActiveX Automation.

OLE Control See ActiveX Control.

OLE DB Data-access interfaces providing consistent access to SQL and non-SQL data sources across the enterprise and the Internet.

OMG Object Management Group. A vendor alliance formed to define and promote CORBA object specifications.

Open Group, The Parent company of a number of standards organizations including The Active Group--now managing the core ActiveX technology, X/Open, and OSF.

OpenDoc An object-oriented architecture designed by IBM that allows compound documents to be created by interchangeable software components.

OSF Open Software Foundation. A vendor alliance to define specifications, develop software, and make available an open, portable environment. Now merged with The Open Group.

ORB Object Request Broker. Manages interaction between clients and servers including the distributed computing responsibilities of location referencing as well as coordinating parameters and results.

Out-of-Process An ActiveX Component that runs in its own separate memory space separate from a container application.

P, Q

PCT Private Communication Technology. Designed to provide secure transactions over the Internet.

PERL Practical Extraction Report Language. An interpreted scripting language, typically used in writing CGI scripts. Originally developed for computers that run the UNIX operating system.

PKCS Public Key Certificate Standard. Syntax standards covering a number of security functions, including a standard way of attaching signatures to a block of data, a form for requesting a certificate, and public key encryption algorithms.

POP3 Post Office Protocol version 3. A messaging protocol commonly used on the Internet. It stores and forwards e-mail to users that log on to the mail server. POP uses the SMTP message format protocol.

PPP Point-to-Point Protocol. The Internet standard for serial communications, PPP defines how data packets are exchanged with other Internet-based systems using a modem connection.

PPTP Point-to-Point Tunneling Protocol. The Internet can be used for low-cost, secure remote access to a corporate network with virtual private networking support on Windows NT. This new protocol works over a local call to an Internet Service Provider to gain secure access to the corporate network using the Internet. PPTP, an open, industry standard, supports the most prevalent networking protocols--IP, IPX, and NetBEUI. Companies can use PPTP to out source their remote dial-up needs to an Internet service provider or other carrier to reduce cost and complexity.

Property A set of characteristics of an object.

Proxy Server A proxy server acts as a go-between, converting information from Web servers into HTML to be delivered to a client computer. It also provides a way to deliver network services to computers on a secure subnet without those computers needing to have direct access to the World Wide Web. Thus, secure sites can run a proxy server on their firewall computer. See also Firewall.

Protocol A mutually determined set of formats and procedures for the exchange of information between computers.


RAD Rapid Application Development. A software development technique for quickly creating applications. It involves working sessions between Information Systems groups and users, who jointly define application requirements and prototype the application to be developed. Such applications are usually graphically oriented and visual, to make coding easy.

RDO Remote Data Objects. In version 2.0, RDO is a high-level object interface that directly calls ODBC for optimal speed, control, and ease of programming.

Repository An enterprise-wide system to store, maintain, control, and protect definitional information in a manner that facilitates sharing among a user-defined suite of development tools. Information stored in a repository includes data definitions, their interrelationships, application codes, and appropriate management information such as plans, rules, and authorizations.

Router An intermediary device on a communications network responsible for making decisions about which of several paths upon which message traffic will flow on a network or the Internet. To do this, it uses a routing protocol to gather information about the network, and algorithms to choose the best route based on several criteria called routing metrics.

RPC Remote Procedure Call. A mechanism that extends the notion of a local procedure call, meaning contained in a single memory address space, to a distributed computing environment. Enables an application to be distributed among multiple computers in a way that is highly transparent to the application-level code.

RSA A public key cryptography for Internet security. This acronym derives from the last names of the inventors of the technology: Rivest, Shamir, and Adleman.

RTP/RTCP Real-time protocol and real-time control protocol, respectively. A packet format for sending real-time information across the Internet. An Internet Engineering Task Force (IETF) standard.


Scalability The capability to use the same software environment on many classes of computers and hardware configurations. While often associated with an evolution to large systems, larger organizations often have need for the same software service to be provided with good performance to both small and large groups of users.

SET Secure Electronic Transactions. A protocol for securing electronic credit card payments when conducting commerce across the Internet, which is broadly supported by companies in the computer and banking industries--including MasterCard and Visa.

Script A kind of program that consists of a set of instructions for an application or utility program. A macro is a kind of script. See JavaScript, JScript, and VBScript.

SDK Software Development Kit.

SEPP Secure Electronic Payment Process. A proposed specification that merged with SST resulting in the SET standard for secure e-commerce transactions.

Server A computer-running administrative software that controls access to all or part of a network and its resources.

SGML Standard Generalized Markup Language. An original documentation markup standard promulgated by primary defense contractors as a standard for the development and display of documentation. HTML is a subset of SGML.

SMP Symmetric Multiprocessing. A multiprocessor architecture in which all processors are identical, share memory, and execute both user code and operating system code.

SMTP Simple Mail Transfer Protocol. The Internet standard protocol for transferring electronic mail messages from one computer to another. SMTP specifies the way that two mail systems interface and dictates the format of control messages that these systems exchange in order to transfer mail.

SNA Systems Network Architecture. A widely used communications framework developed by IBM to define network functions and to establish standards for enabling its different models of computers to exchange and process data. SNA contains separate layers. As changes occur in one layer, no other layer need be changed. An IBM-developed layered network architecture that isolates applications from system network services, so developers can write applications independent of the lower-level networking software layers.

SNMP Simple Network Management Protocol. SNMP (RFC-1157) is the Internet's standard for remote monitoring and management of hosts, routers, and other nodes and devices on a network. A TCP/IP-derived protocol governing network management and monitoring network devices.

SOM System Object Model. IBM's object model for applications that run on a single system. See also DSOM.

SQL Structured Query Language. The international standard language for defining and accessing relational databases.

SQL Access Group (SAG) A consortium of vendors established in November 1989 to accelerate the Remote Data Access standard and to deliver protocols for interconnectivity among multiple SQL-based software products.

SSL Secure Sockets Layer. A standard for providing encrypted and authenticated service over the Internet. Uses RSA public-key encryption for specific TCP/IP ports. Intended for handling commerce payments. An alternative method is Secure-HTTP (S-HTTP), which is used to encrypt specific WWW documents rather than the entire session. SSL is a general-purpose encryption standard.

Stored Procedures Pre-compiled software functions that are managed and run within a remote database management system (RDBMS). Stored procedures provide a reusable service that can be shared by multiple applications and users. They typically capture business processes and data manipulation functions that are part of the server-side of a client/server application.

STT Secure Transaction Technology. A proposed specification that merged with SEPP resulting in the SET standard for secure e-commerce transactions.

Synchronous A function that does not allow further instructions in the process--code--to be executed until the function returns a value. A function that uses no redundant information to identify the beginning and end of characters, and thus is faster and more efficient than asynchronous transmission, which uses start and stop bits. The timing is achieved by transmitting sync characters in front of data characters; usually, synchronization can be achieved within the transmission time for two or three characters.


T.120 A set of protocols for transport-independent, multi-point data conferencing that is an ITU standard.

T1 An AT&T term for a transmission facility at digital signal level 1 (DS1) with 1.544 Mbps in North America and 2.048 Mbps in Europe. The bit rate is with the equivalent bandwidth of approximately twenty-four 56Kbps lines. A T1 circuit is capable of serving a minimum of 48 modems at 28.8Kbps, or 96 modems at 14.4Kbps. T1 circuits are also used for voice-telephone connections. A single T1 line carries 24 telephone connections with 24 telephone numbers. When used for voice transmission, a T1 connection must be split into 24 separate circuits.

T3 An AT&T term for a transmission facility at digital signal level 3 (DS3). Equivalent in bandwidth to 28 T1s. The bit rate is 44.736 Mbps. T3 is sometimes called a 45meg circuit.

TCP/IP Transmission Control Protocol/Internet Protocol. TCP/IP is a combined set of protocols that perform the transfer of data between two computers. TCP monitors and ensures correct transfer of data. IP receives the data from TCP, breaks it up into packets, and sends it to a network within the Internet.

Telnet A terminal emulation protocol users can employ to log on to other computers on the Internet. Alternatively, software that can be used to log on to another computer using the telnet protocol.

Three-tier Architecture See Multi-tier Architecture.

Transaction A group of processing activities that are either entirely completed, or if not completed, that leave the database and processing system in the same state as before the transaction started.

TP Transaction Processing. The real-time handling of computerized business transactions as they are received by the system. Also called online transaction processing (OLTP) systems.

Two-tier Architecture See Client/Server Architecture.


URL Uniform Resource Locator. An address that uniquely identifies a World Wide Web site, usually preceded with http:// such as in this fictitious URL A URL can contain more detail, such as the name of a page of hypertext, usually identified by a suffix of .html or .htm.


V.120 This protocol allows ISDN modems to transfer files. It is typically used to connect to ISDN-capable BBSs. Connecting to an Internet service provider over ISDN uses PPP or MPPP rather than V.120 to establish communications.

VBA Visual Basic, Applications Edition. The development environment and language found in Visual Basic that can be hosted by applications. VBA supports expert users and developers, extending the functionality of software products. Office 97which includes Microsoft Word, Microsoft Excel and Microsoft Accesshosts VBA 5.0, as does Visio Professional. In addition, over 50 companies which are licensing VBA to be included in over 100 products.

VBX Visual Basic Extension. Custom controls originally designed for 16-bit applications created by Visual Basic. Visual Basic version 4.0 introduced the ActiveX Control (OCX) model as its main control architecture in order to support controls in both 16-bit and 32-bit environments.

Virtual Machine The mechanism the Java language uses to execute Java bytecode on any physical computer. The VM converts the bytecode to the native instruction for the target computer.

Virtual Root Also Vroot. A virtual tree of Web aliases that points to local, physical directories. This simplifies client URL addresses by presenting an entire set of content directories as a single directory tree.

VRML Virtual Reality Modeling Language. A language for coding three-dimensional HTML applications.


W3C World Wide Web Consortium. Founded in 1994 to develop common standards for the World Wide Web, the W3C is an international industry consortium, jointly hosted by the Massachusetts Institute of Technology Laboratory for Computer Science (MIT/LCS) in the United States; the Institut National de Recherche en Informatique et en Automatique (INRIA) in Europe; and the Keio University Shonan Fujisawa Campus in Asia. Initially, the W3C was established in collaboration with CERN, where the Web originated, with support from DARPA and the European Commission. You can read more about them on the Web site at

Web Application Also Web-based Application. A software program that uses HTTP for its core communication protocol and delivers Web-based information to the user in the HTML language.

Windows Sockets Also Winsock. Winsock provides a single interface in Microsoft Windows to which multiple network software programs conform. A Winsock will typically be available in a dynamic link library named winsock.dll. This communicates on one side with network programs and on the other side with the TCP/IP protocol to facilitate Internet communications.

World Wide Web Also the Web or WWW. A set of services that run on top of the Internet providing a cost-effective way of publishing information, supporting collaboration and workflow, and delivering business applications to any connected user in the world. The Web is a collection of Internet host systems that make these services available on the Internet using the HTTP protocol. Web-based information is usually delivered in the form of hypertext and hypermedia using HTML.

WOSA Windows Open Services Architecture. An architecture and set of application programming interfaces for Windows that standardized the interfaces developers use in accessing underlying network services.

WYSIWYG What You See Is What You Get. Authoring software programs that render a document on the computer screen the way it will appear in print, even as it is being edited.

X, Y, Z

XA A transaction interoperability standard defined by X/Open. This API provides a consistent way for transaction processing systems, called a Transaction Manager, to work with Resource Managers, such as relational databases or another transaction manager, to ensure that all the steps in a business process are completed as a unit or not at all. The Microsoft Transaction Server uses XA to connect with other transaction processing systems.

X.500 (including DAP). Directory Access Protocol developed by the ITU, is a standard for global directory services. X.500 defines object classes for a directory and a method for accessing names from a directory. The DAP X.500 protocol supports generalized browsing, directory administration, schema management, full authentication, and the infrastructure for internationalization.

X.509 Certificate A protocol for a cryptographic certificate that contains a vendor's unique name and the vendor's public key.

X/Open An independent consortium of international computer vendors created to establish multi-vendor standards based on de facto and de jure standards.

For more detailed information, refer to the Microsoft Press Computer Dictionary, Second Edition at your local computer or book store. Or you can order it from Microsoft Press® at

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