DCOM COM Interview Question:

What is the difference, if any, between OLE and COM?

Submitted by: Administrator

OLE is a set of technologies to support linking and
embedding. COM lies in OLE as one of the technologies. COM
defines a binary standard / set of rules for developing
reusable components.
Submitted by: Administrator

OLE
Is Windows 3.0's most exciting technology: the abilty to
Embed and Link Objects between applications. It's first
incarnation was based on DDE dialogs.

COM
When OLE expanded, it was obvious that DDE was not firm
grounds, so Microsoft decided to create a new foundation. A
binary compatible, language independent, extremely
lightweight (practicaly no runtime) protocol. That is the
Component Object Model. It defines binary interfaces and
allows programmes to commit to them (implement) and use
those functional contracts.

OCX
One of the most natural uses of COM was the replacement of
old Visual Basic controls (VBX) for 32 bit more usable Ole
Custom Controls (OCXs). There was a set of interfaces that
allowed you to expose your object to be used on fellow
programmer's toolbox.

ActiveX
Enter the Internet and Internet Explorer. Microsoft wanted
to make the Web Browser experience richer and so you could
embed an OCX as part of a page content. Problem was, the
ammount of required interfaces was too large and
downloading such entities on demand required time. So the
standard was trimmed down to the necessary interfaces and
renamed ActiveX. An ActiveX control is simply any COM
object.

And all this is history, I mean, the new grounds for
Microsoft technology is now .NET and not COM. Problem is,
there isn't a replacement for OLE (embedding, drag and
drop, etc) -at least that I know of- based upon .NET.
Submitted by: Smith