> -----Original Message----- > From: IBM Mainframe Discussion List > [mailto:[EMAIL PROTECTED] On Behalf Of Paul Gilmartin > Sent: Tuesday, May 08, 2007 6:27 PM > To: [email protected] > Subject: Re: jcl. > > > On Tue, 8 May 2007 11:50:49 -0500, Weidt, James wrote: > > >Ahhhhh!!! The search for the holy grail continues!!! > > > Indeed. > > I've noticed that if I create a symbolic alias with such as: > > DEFINE ALIAS( NAME( user.WHATEVER ) - > SYMBOLICRELATE( user.WHATEVER.D&YYMMDD ) ) > > ... I can use that alias to access existing data sets > (DISP=OLD) incorporating today's date. But if I try to > create a data set (DISP=NEW), the job fails. Bummer. I > think I understand the logic that leads to the failure. Still bummer. > > But, doesn't this mostly dispel the rationale repeatedly > given for not allowing references to &YYMMDD in batch JCL, > viz that earlier processes (Reader? Converter? Other?) need > to know how system symbols will be resolved to build real > data set names?
I don't think so. The date at which the DEFINE occurs and the system upon which it occurs is known at the time of the DEFINE. With JCL, the concept of "date" is generally ill defined and could be argued for many interpretations. Such as: (1) Reader Start Date; (2) Job start date; (3) step start date; or perhaps even (4) date when the dataset was first OPENed by the step in which it was defined. Personally, I like (1), but others might argue for the other possibilities. In the case of (2), what about for a job which uses z/OS step restart? Which job start date? The original job start date or the date upon which the job was restarted? Or perhaps even worse would be if someone wanted to "integrate" this with a product such as CA-11. Again, which job start date? Or even which Reader Start date? An STC does not have this particular problem. Similar for other system symbols in a parallel sysplex. When, exactly, is the symbol resolved. The "simpliest" think that I have thought of is a JES exit (reader exit?) which inserts // SET JCL statements after the JOB statement which set a JCL symbol which has the same name as a system symbol. This, of course, means that the symbols are created at job read in type on the system upon which it is read in. May be useful, but then again maybe not. > > And how would the JES3 scheduler deal with such a construct? > > -- gil -- John McKown Senior Systems Programmer HealthMarkets Keeping the Promise of Affordable Coverage Administrative Services Group Information Technology This message (including any attachments) contains confidential information intended for a specific individual and purpose, and its content is protected by law. If you are not the intended recipient, you should delete this message and are hereby notified that any disclosure, copying, or distribution of this transmission, or taking any action based on it, is strictly prohibited. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
