What is OLE?
OLE (Object Linking and Embedding) is Microsoft's component document technology. With OLE, it is possible to dynamically link files and applications together. An object is a combination of data and the application needed to modify that data. Objects can be embedded in or linked to documents created with a different application.
For instance, an Excel spreadsheet can be embedded within a Microsoft Word document using OLE. Double-clicking the embedded spreadsheet will launch Excel and allow the user to modify the sheet.
Some applications include small applets that are used to create objects. For instance, Microsoft Word includes a drawing tool (MS Draw) and a tool for manipulating characters as art (Text Art) which can be launched only via OLE.
For more information, visit Microsoft's Developer Network page at: http://msdn.microsoft.com/default.aspx
What are COM, COM+, and DCOM?
COM (Component Object Model) is Microsoft's component software architecture developed primarily for Windows. It is the foundation upon which OLE and ActiveX are based, and provides a means to re-use code without requiring re-compilation. In COM, a component is a platform-specific binary file that compliant applications and other components can utilize. Programs incorporating a component's services never have access to its internal data structure, but instead include pointers to its standardized interface. Thus, it is possible for components to interact with each other regardless of how they work or what language they are written in.
COM+ is an enhanced version of COM that provides better security and improved performance. DCOM (Distributed Component Object Model) is an extension of COM that allows applications and components to communicate with each other over a network.
For more detailed information about COM, COM+, DCOM, and related technologies, visit: http://www.microsoft.com/com/default.mspx
What is ActiveX?
ActiveX is a term Microsoft uses to describe a number of its COM technologies. However, when most people say "ActiveX", they are really referring to ActiveX controls, Microsoft's answer to Java applets. The two technologies are similar in that they are designed to be downloaded and executed by web browsers. The difference is that while ActiveX controls can interface with Microsoft Windows better than Java can, they offer very little cross-platform support.
For more information about ActiveX controls as well as other ActiveX technologies, visit Microsoft's page at: http://www.microsoft.com/com/default.mspx CNET maintains a library of ActiveX controls, available at the following address: http://www.download.com/2001-2206-0.html?legacy=cnet
What are ActiveX controls?
ActiveX controls are small program building blocks that can be used to create distributed applications that work over the Internet through web browsers. Examples include customized applications for gathering data, viewing certain kinds of files, and displaying animation.
The ActiveX programming specification is an extension of Microsoft Windows and the Object Linking and Embedding (OLE) API. ActiveX applications are used mainly with Microsoft's Internet Explorer web browser.
Like Java applets, programs that use ActiveX controls run on the client computer, not the server.
For more information about ActiveX controls as well as other ActiveX technologies, visit Microsoft's page at: http://www.microsoft.com/com/default.mspx
A software architecture developed by Microsoft to build component-based applications. COM objects are discrete components, each with a unique identity, which expose interfaces that allow applications and other components to access their features. COM objects are more versatile than Win32 DLLs because they are completely language-independent, have built-in interprocess communications capability, and easily fit into an object-oriented program design. COM was first released in 1993 with OLE2, largely to replace the interprocess communication mechanism DDE used by the initial release of OLE. ActiveX also is based on COM.