Functions Moved to the Kernel
As Mathematica continues to be enhanced, it is sometimes useful to move functionality previously implemented as add-on packages to the kernel. This allows a function to take advantage of internal features of the kernel. In Version 5, several packages and functions became kernel functions.
Packages with functionality moved into the kernel.
The following is a summary of the changes involved. Detailed information about the use of the kernel versions of these functions can be found in The Mathematica Book.