One reasonably common issue that arises, which can result in a multitude of different errors, relates to JCL comment continuations being overlooked.

Take for example the following JCL that allocates ISPF panel and messages library concatenations ISPPLIB and ISPMLIB, respectively:

Now look at the output created when the job is executed. First the JESJCL output file:

And this in JESYSMSG:

Note that:

a) unlike all other datasets in the ISPPLIB and ISPMLIB concatenations, dataset CMNSUP.INTL.CMN830.PANELS is not preceded by a number in the JESJCL output.

b) the JESYSMSG output file shows only one dataset being allocated and released under the ISPPLIB DD statement, unlike ISPMLIB which shows all three datasets being allocated/released.

This behaviour occurs because the comment starting in column 55 of the first ISPPLIB DD statement continues into column 72, which is also non-blank. This acts as a comment continuation statement that effectively makes the following card a comment, too, regardless of the fact that it does not start ‘//*’.

If the comment continued beyond column 72 but column 72 were blank then the following line would NOT be treated as a JCL comment.

Always take great care when editing any ZMF-related JCL, i.e. Server started task, custom skeletons, housekeeping jobs, etc., to avoid inadvertently continuing JCL comments over multiple lines.