When to Use Each ALLOCOPT Option

For regular (large volume) reports, it is recommended not to use the ALLOCOPT options. The best performance and results are achieved with the "classical" CDAM technique.

ALLOCOPT=JOBSDSN2 should be used for decollating many short sysouts, where each sysout has different printing characteristics (for example, different CHARS). Since a SYSDATA entry is developed for each sysout, the printing characteristics are not lost. An advantage to this option is the efficient use of CDAM space since, many short reports are compressed into a combined area (without any unused free space).

ALLOCOPT=JOBSDSN1 should be used for decollating many short sysouts, where each sysout has the same printing characteristics. (If they differ only by the type of page control characters, machine or ASA, they can be treated similarly.) An example is generic decollating of job MSGCLASS outputs. Since only one SYSDATA entry is developed for each job, only a limited amount of space is used in the User Reports List files. Another important advantage is the efficient use of CDAM space, since many short reports are compressed to a combined area (without any unused free space). This method is the most space-efficient and results in faster decollation.

Use ALLOCOPT=ONEDSN under the same conditions as ALLOCOPT=JOBSDSN1 when a separate CDAM dataset is required for each job.