Agree, agree, agree! The single TIOT is a limit to "virtualization." I could write an "executive" to run multiple application programs simultaneously as a single jobstep with separate TCBs. The usefulness of a general such solution is limited by the lack of independent DD's for each program. Yes, saying what Gil says differently, if each of the programs support DD override I could do it that way, but that's a big if.
To give a practical example, it might be nice to write an executive that would ATTACH multiple FTP clients, so one could run a bunch of related file transfers in parallel. But the FTP client program does not allow the overriding of 'INPUT' and 'OUTPUT' as DD names, so the lack of independent TIOTs precludes this idea. Charles -----Original Message----- From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf Of Paul Gilmartin Sent: Tuesday, January 10, 2017 8:34 AM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: "task level" TIOT & XTIOT? A crazy thought? On Tue, 10 Jan 2017 07:27:12 -0600, John McKown wrote: > >So, have you ever wanted to run multiple, concurrent, executions of >some program which does not accept an alternative DD name list? For >instance, some in-house COBOL program. Wouldn't it be kind of nice to >be able to specify some parameter, such as NEWTIOT=YES so that the >program being attached would have its own, "private" TIOT & XTIOT, >which would then propogate to any of its children TCBs which did not have a >NEWTIOT=YES. >Hum, it might even be nice to be able to list which DDs are to be >"passed down", a bit like you can say whether or not to share a >specific SUBPOOL with a subtask. That might be nice for something like >SYSPRINT. > It has long been my perception that IBM has a penchant for providing valuable facilities at implementation layers that limit their usefulness. I consider the alternate DDNAME list an example. Rather, it should be an additional argment to ATTACH, implemented by code in ATTACH and OPEN, and quite transparent to the child task. And rather than positional it should have apparent/real DDNAME pairs. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
