Charles Mills wrote: "DISP=" -- which includes the current status of the dataset -- NEW, MOD, OLD -- is for both the dataset AND the member. This is not the case. Worse, he has been admonished about this error repeatedly. In the past he would have been in great danger. The Inquisition would almost certainly labelled him as not just a heretic but an obdurate one, and things would not have gone well for him. AS I and others have already noted that the question whether a PDS[E] member named <member> exists is 1) moot until the question whether that PDS[E] itself exists is resolved and 2) need not be reached to explain the behavior that has been dsecribed here. DISP=MOD goes back to OS/PCP. In those days it was usual to explain the difference between DISP=NEW and DISP=MOD to novices by saying something like o DISP=NEW means create it, then use it; and o DISP=MOD means create it is it does not exist, then use it. Novices usually encountered DISP=MOD first in cataloged procedures. A common sequence of job steps was o compile A, writing the object module produced to SYSLIN, o compile B, writing the object module produced to SYSLIN, etc., o link these object modules to obtain a load module, and o execute this load module briefly, i.e., until the first fatal error occurred. In these circumstances both SYSLIN and SYSLMOD were often temporary data sets, and DISP=MOD was used in cataloged procedures that defined them in order to permit compiles and, less commonly, link edits and executions to be to be stacked up in separate successive steps of the same job. In the first job step, that for A above, SYSLIN did not exist; and it was thus both created and used; in the second jobstep it did exist and was used, etc., etc. The same cataloged procedure could ber and was used for both. Conceptually similar schemes still have uses; the contextual distinction between DISP=MOD and DISP=NEW remains useful; and what anyway is all of this pother about?
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