Provided is a method, system, program, and data structure for applying a
patch to a computer system, wherein the patch includes content to add to the computer.
A computer object is generated to include configuration information on the determined
installed components. At least one patch includes content to add to the computer
and is capable of being associated with at least one realization, wherein each
realization defines a state of the computer. For each realization, a determination
is made from the configuration information in the computer object as to whether
the state defined by the realization exists in the computer. Data is written to
the computer object indicating whether the state defined by the realization exists
on the computer. The computer object is used to determine whether each patch is
compatible with the installed components of the computer.