The ICFRU relies on the fact that catalog management routines log each catalog change to SMF (if you are recording the appropriate SMF record types). These SMF records contain images of the catalog records that can be combined with the catalog records from an IDCAMS EXPORT copy of a catalog to build a data set functionally identical to an IDCAMS EXPORT copy of the catalog as if it had been taken after the changes logged to SMF were applied. The new "EXPORT data set" can then be reloaded using IDCAMS IMPORT, thus recovering the catalog to the point of failure (or to the specified time).

There are actually two programs in ICFRU: Integrated Catalog Forward Recovery Record Selection and Validation (CRURRSV) and Integrated Catalog Forward Recovery Record Analysis and Processing (CRURRAP). Record Selection and Validation processes SMF dump data sets, extracting appropriate records that are then sorted and processed, together with an EXPORT copy, by Record Analysis and Processing to produce a data set, to be imported. See Figure 1.