On Thu, Jul 23, 2015 at 8:36 AM, David Evans <[email protected]> wrote:
> I am probably over simplifying the issue or I am sure the smart folks at > IBM would have done this already but it seems to be that if the DSN ENQ > included a VOLSER, then the system would be able to distinguish between a > truly ENQ Dataset and one that has the same name of an ENQ Dataset that > resides on another volume. If the file is really in use, I would want to > have the protection of jumping through hoops to make sure this is done by > someone who truly understands what they are doing and its possible impact. > I had thought the same thing. But, first, what volser would be in the ENQ name? The first problem is that, for JCL at least, the ENQ for a DSN referenced in the JCL is done by the initiator at job start time, before the first step starts. So any DISP=NEW data sets don't have a volume yet. And they won't until, and unless, the creating step is initiated. So there's a problem just to start with. There there is the question of "which volser in the ENQ"? For existing DSNs, should it be just the first of a multi-volume DSN (but what if somebody does a VOL=SER=...... for the 2nd volume of a 3 volume set?), or every volume in a multi-volume. What about when the DSN extends to a new volume? I guess that would require another ENQ to be issued. So we need to be sure the system can do so at the proper time. And what to do if the ENQ fails at that point? Select another volume? Wait? Abend? There are likely more impediments that I just can't think of at present. > David Evans > -- Schrodinger's backup: The condition of any backup is unknown until a restore is attempted. Yoda of Borg, we are. Futile, resistance is, yes. Assimilated, you will be. He's about as useful as a wax frying pan. 10 to the 12th power microphones = 1 Megaphone Maranatha! <>< John McKown ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
