COM, OLE - What is it?

COM - What is it?
The Component Object Model provides standard interfaces and inter-component communications. COM is a Microsoft concept used to communicate between components on the same computer. Components from different machines can be combined using DCOM.

Through COM, an application may use features of any other application object or operating system, or allow for software component upgrades without affecting the operation of the overall solution. COM can be used by developers and system integrators to create customized solutions.A binary standard, COM is generic and and is the core of DCOM,ActiveX, and OLE technology.

OLE - What is it?
Object Linking and Embedding is used to provide integration among applications, enabling a high degree of application compatibility, even among diverse types of information, OLE technology is based on COM, and allows for the development of reusable, plug-and-play objects that are interoperable across multiple applications (see accompanying OLE Automation definition). It also provides for reusable, component-based software development, where software components can be written in any language, supplied by any software vendor.

OLE Automation - What is it?
OLE Automation and the underlying COM technologies were designed by Microsoft to allow components (written in C and C++) to be used by a custom program (written in Visual Basic or Delphi).This model provides a precise match for the needs of the processcontrol industry, with hardware developers writing software components in C and C++ for handling data access from a device.Through OPC, application developers can write code in any language necessary to request and utilize plant-floor data.