Because DSE lets you perform arbitrary actions without imposing any logical constraints, you must ensure that they are applied to the proper file.

First, verify that gtmgbldirnames an appropriate Global Directory. Check the definition with the printenv command. You may create or use Global Directories that differ from the "normal" Global Directory. For instance, you might create a Global Directory that mapped all global names except a normally unused name to a file with integrity problems, and map that unused name to a new file. Then you could use MUPIP to CREATE the new file and use DSE to SAVE blocks from the damaged file and RESTORE them to the new file for later analysis.

When you initiate DSE, it operates on the default region specified by the Global Directory. Once DSE is invoked, use FIND -REGION to determine the available regions, and then to select the appropriate region. The technique of creating a temporary Global Directory, with the target region for the repair as the default region, prevents accidental changes to the wrong region.