BCL (Base Class Library) vs FCL (Framework Class Library)

Question

What\'s the difference between the two? Can we use them interchangeably?

Answer 1

The Base Class Library (BCL) is literally that, the base. It contains basic, fundamental types like System.String and System.DateTime.

The Framework Class Library (FCL) is the wider library that contains the totality: ASP.NET, WinForms, the XML stack, ADO.NET and more. You could say that the FCL includes the BCL.