RACF Class Descriptor Table (CDT) Overview

The RACF Class Descriptor Table (CDT) contains information that directs the processing of general resources. The CDT contains the names and attributes of the general resource classes that can be used by RACF.

The class descriptor table has two parts:

  1. The static Class Descriptor Table:
    • It contains 2 modules:
      1. ICHRRCDX – contains the RACF classes provided by IBM. The classes defined in ICHRRCDX are required and should not be deleted or modified.
      2. ICHRRCDE – contains installation defined RACF class entries. This is an optional module. To define RACF classes in ICHRRCDE, we need to use the ICHERCDE macro.
    • Any changes made to the static CDT requires an IPL, which is why this area is know as static CDT.
  2. The dynamic Class Descriptor Table:
    • Contains installation defined class entries built from the CDT general resource class.
    • This area of the CDT is optional.
    • Classes can be defined in the RACF dynamic CDT using the RDEFINE and RALTER commands.
    • Any changes done to the RACF dynamic CDT require the command SETROPTS RACLIST(CDT) REFRESH to be issued. It does not require an IPL.


  • RACF processing references the class descriptor table whenever a class name is received as input.
  • Each class, if defined on multiple systems, must be defined identically on all systems. If the classes are defined differently, unpredictable results can occur when you change the SETROPTS options for the class.
  • Consider migrating your static CDT entries from ICHRRCDE to the dynamic CDT.


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