-----Original Message----- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Johnny Luo Sent: Tuesday, July 10, 2007 10:47 AM To: IBM-MAIN@BAMA.UA.EDU Subject: JOB STEP TASK and REGION parm
Hi, <SNIP> 1. To get a job step task, you first need to have an authorized job step task. It's interesting, like the classic egg-and-chicken problem. Anyway, in Z/OS we can get our 'first-level' job step task using START and LOGON command, and a batch job. And they all require a jcl where the REGION parm can be specified. Don't know whether extra interfaces exist. 2. A job step task has its own TIOT and JSCB. And its TCBJSTCB points to itself. This is the biggest difference I know between a job step task and a normal task. The result is that a job step task can get more Independence as far as the its relationship with its mother is concerned. <SNIP> I may have cut too much here, but I think you are confusing a few things. Your job step TCB (TASK) and all the others you were asking about are all in the same address space. The REGION parameter affects all those tasks in that address space. Any TCB can build/have its own TIOT that is different from any other TCB with in the Address Space. This probably is not a good thing to do, particularly if you do not understand the whole I/O processing scheme in "MVS". Typically, we see ONLY ONE TIOT at the JOB STEP task (TCB) level and this is then used by all the other TCBs attached below that physical TCB. System TCBs above "your" TCB may do things a bit differently because of needs that JES2/3 and the system may have for controlling system resources. I hope this helps you with your visualizing how things are constructed. Regards, Steve Thompson ---------------------------------------------------------------------- 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
