  The computing model for the Collider Detector at Fermilab (CDF) scientific
experiment has evolved since the beginning of the experiment. Initially CDF
computing was comprised of dedicated resources located in computer farms around
the world. With the wide spread acceptance of grid computing in High Energy
Physics, CDF computing has migrated to using grid computing extensively. CDF
uses computing grids around the world. Each computing grid has required
different solutions. The use of portals as interfaces to the collaboration
computing resources has proven to be an extremely useful technique allowing the
CDF physicists transparently migrate from using dedicated computer farm to
using computing located in grid farms often away from Fermilab. Grid computing
at CDF continues to evolve as the grid standards and practices change.
