Dynamic allocation? Just in time dynamic allocation DISP=OLD of the viewable dataset?
Charles -----Original Message----- From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf Of Bob Bridges Sent: Monday, March 30, 2020 8:51 AM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: PARM= vs PARMDD= and symbol substitution It's beginning to sound like z/VSE is an improvement in several ways on z/OS. I wrote a production job recently that updates a dataset pretty much anyone can View (a list of current Top-Secret ACIDs to see what so-and-so's ACID is, or who belongs to ACID such-and-such). The update has to read a largish-security database. The last step is a SORT that takes less than a second - but I had to put it in a separate job, and have it triggered by the previous job, because otherwise the dataset would be unavailable for Viewing by any user while the long job was running. --- Bob Bridges, robhbrid...@gmail.com, cell 336 382-7313 /* There is no harm in being sometimes wrong — especially if one is promptly found out. -John Maynard Keynes, Essays in Biography (1933) */ -----Original Message----- From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf Of Tony Thigpen Sent: Monday, March 30, 2020 11:38 Actually, there is no 'allocation' of a file by z/VSE during the JCL processing. The file is only 'allocated' once it is opened and 'unalocated' once the program closes the file. For instance, if you have a 5 hour program, that just needs to update a 'totals' VSAM file at the end of the 5 hours, as long as the program does not open the file until it needs the file, any other program can use, including updating, the file until that time. So, basically, you 'own' the file only while you have it opened. One ramification is that you can't create a file simply by having in the jcl, like in z/OS. You have to open it to create it. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
