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IMS function levels overview

An IMS function level identifies a PTF that contains one or more IMS functions. The function level is a full word hexadecimal number, which is represented as decimal in output for the QUERY IMSFUNC command and in messages.

The following types of IMS functions are identified by using IMS function levels:
  • A PTF that contains one small, usable piece of an overall function
  • A new, significant function that is delivered enabled
  • Previously optional functions that are changed to be mandatory
  • Large, complex fixes
You can see the current IMS function level at the following locations:
  • The IMS checkpoint ID table, which includes the function level in the BCPFLVL field
  • The IMS functions enabled bitmap

You can also use the QUERY IMSFUNC command to see the current IMS function level and the function level at which a function was added.

The IMS functions enabled bitmap, which is mapped by the not-OCO DFSFNCE macro, contains the current IMS function level and a bit for every IMS function that is enabled. You can access the bitmap by using the SCD field SCDFNCE. IMS components, including but not limited to IMS database, IMS catalog, MSC, Fast Path, OTMA, and IMS scheduling, might also store an extra function enablement bit in a component control block. When two function enablement bits are defined, one in the IMS functions enabled bitmap and one in the component control block, IMS cold start sets both bits based on the PROCLIB member function enablement parameter and UPDATE IMSFUNC sets (or resets) both bits based on the SET parameter specified.

If an IMS function is not enabled by default, you can enable the function by using one of the following methods:
  • Statically by specifying a parameter in the DFSDFxxx member of the IMS PROCLIB data set and cold starting IMS.
  • If SCI and OM are enabled, dynamically by using the UPDATE IMSFUNC command after the PTF containing the function is applied to an IMS system for local functions or to all IMS systems for global functions.

IMS function names and levels

The following table shows function information that you can use to run the QUERY IMSFUNC or UPDATE IMSFUNC commands.

Function name Function level DFSFNCE function-enabled bit
FUNCTIONLEVEL 00000001 None
DEDBGT2K 00000002 FNCE_DEDBGT2K
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