Changing the parameters of an existing allocation

When dynamic allocation uses an existing allocation to satisfy a dsname allocation request, some of the parameters of the existing allocation might have to be changed to match the parameters specified in the request. Only existing allocations that were dynamically allocated, with the convertible attribute, can have their parameters changed. (The convertible attribute is described in Convertible attribute.) Resources allocated through JCL or the TSO/E ALLOCATE command cannot have their parameters changed (with the exception of status and disposition specified through JCL), but they may be used if no changes are necessary.

The following parameters are eligible for change by dynamic allocation:

Ddname
Member name
Status
Normal disposition
Conditional disposition
Space
Deallocation at CLOSE
Input only
Output only
DCB attributes
Password
Permanently allocated attribute.

No other parameters may be changed.

Note:

You cannot change an exclusive status to shared status. For example, you cannot change OLD to SHR. However, it is possible to change SHR to OLD if no other jobs are enqueued on the requested data set.
You cannot change the parameters on an explicitly referenced OUTPUT JCL statement (DALOUTPT).

The status (DALSTATS) of an existing allocation to be reused/converted must always be SHR, OLD, or MOD. A Dynamic Allocation Information Retrieval request may return a status (DINRTSTA) of NEW for that existing allocation, because DINRTSTA will return the status as of the beginning of the step. DALSTATS must specify the status at the time that the dynamic allocation is being performed. See Obtaining allocation environment information for more on requesting allocation status.

    If a DD statement created the allocation environment as NEW:

          //OUTDATA  DD  DSN=TSI.TP31.DEV.OUTDATA.KAM,
          //             DISP=(NEW,DELETE),
          //             UNIT=SYSDA,SPACE=(TRK,(9,9),RLSE)

    and you specify Information retrieval as:

           DINDDNAM  'OUTDATA '

    and receive back information as:

           DINRTDSN              'TSI.TP31.DEV.OUTDATA.KAM'
           DINRTSTA              X'04' (NEW)       <=============
           DINRTNDP              X'04' (DELETE)
           DINRTCDP              X'00'
           DINRTATT              X'20' (Permanently allocated)
           DINRTTYP              X'00'

    In order to convert the Normal Disposition from DELETE to CATLG
    you must specify:

           DALDDNAM  'OUTDATA '
           DSLDSNAM  'TSI.TP31.DEV.OUTDATA.KAM
           DALSTATS  X'08' (OLD)         <===================
           DALNDISP  X'02' (CATLG)
           DALPERMA