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The effect of CONTIG

It is possible to insist, but not force, the primary request to be satisfied in a single extent.

The effect of using the CONTIG operand within SPACE.

Without CONTIG, if the free space is fragmented the system will attempt to allocate the request in up to 5 extents, and if the primary request cannot be satisfied, in up to 5 extents, then the job will fail JCL error, "Space Requested Not Available".

As with earlier examples the requested space is to be allocated in cylinders, with a primary request for 15, and a secondary request for 5.

//ddname DD SPACE=(CYL,(15,5),,CONTIG)

The system will allocate the PRIMARY request in 1 extent whenever possible. CONTIG is not applicable to secondary requests.

Without CONTIG,if the free space is fragmented the system will attempt to allocate the request in up to 5 extents.

Be aware that using CONTIG may increase the risk of JCL error, "Space Requested Not Available", but this may be preferable to an SB37 during execution.