Specification and Conceptual perspective class diagrams

[Puja Potdar]

What is Specification and Conceptual perspective class diagrams? What is the difference between the two?

[Junilu Lacar]

Martin Fowler's "UML Distilled" discusses this. Haven't got it with me right now but basically, the Conceptual perspective is a higher-level view that is concerned with identifying concepts (go figure) in the problem domain. It is does not take implementation details (language, platform, etc.) into consideration.
The Specification perspective is still high-level but is now looking more into the software side. This perspective still stays at the interface level (vs. implementation).
The third perspective mentioned in Fowler's book is the implementation perspective. This perspective is the "bare metal" view and goes into the details of classes and the target language and platform.
Again, if you want more, try using the search facility or get a copy of the "UML Distilled" book.
HTH,
Junilu