.NET distinguishes between private and shared “Assemblies.”
With COM, all components are globally available by a registry configuration.
All COM objects have a unique identifier that consists of a 12S-bit number and is also known as class ID
The COM API call to create COM objects, CoCreatelnstance ( I,just looks into the registry to
find the CLSID and the path to the DLL or EXE to load the DLL or launch the EXE and instantiate the
BeCause such a 128-bit number cannot be easily remembered, many COM objects also have a ProgID.
The ProgID is an easy-to-remember name, such as Excel.Application, that just maps to the CLSID.
In addition to the CLSID, COM objects also have a unique identifier for each interface (IID) and for the
type library (typelib ID).
Information in the registry is discussed in more detail later in the chapter.