  In this paper the concept of unbounded Fredholm operators on Hilbert C*-
modules over an arbitrary C*-algebra is discussed and the Atkinson theorem is
generalized for bounded and unbounded Feredholm operators on Hilbert C*-modules
over C*-algebras of compact operators. In the framework of Hilbert C*-modules
over C*-algebras of compact operators, the index of an unbounded Fredholm
operator and the index of its bounded transform are the same.
