The IDMS startup module RHDCOMVS has aliases - IDMSDC and IDMSCV.
If the startup JCL of an IDMS CV specifies EXEC PGM=IDMSDC or EXEC PGM=IDMSCV, then care must be taken when RHDCOMVS is updated by maintenance.
Release : All supported releases.
Component : IDMS/DB
As part of the maintenance process, many clients manually copy the modules that have been updated by PTFs from the SMP/E controlled CAGJLOAD to a separately maintained LOADLIB which is in the STEPLIB and CDMSLIB of the CVs.
If the copy is done with an IEBCOPY batch step, aliases are not automatically included in the copy of RHDCOMVS, they must be specifically referenced in the IEBCOPY input.
Therefore, if the CV's JCL executes IDMSDC or IDMSCV and only RHDCOMVS was in the IEBCOPY input, then IDMS will not pick up the modified RHDCOMVS at execution time.
This is not a problem if RHDCOMVS is copied online with ISPF option 3.3 - in that case, the aliases are automatically copied as well.
Copying Members That Have Alias Names (COPY Statement) (IBM documentation page)