On Sun, 7 Sep 2025 18:08:10 -0500, Jon Perryman  wrote:
>
>I should have said "many" people. I'll assume you know how to multi-task TSO 
>commands and REXX. What is your explanation why TSO and ISPF do not support 
>multi-tasking? 
>
Perhaps the developers didn't understand multitasking.
Or concluded that the benefit didn't justify the development
cost.

>What is the problem with using UNIT=VIO or in storage VSAM? Do you think pipes 
>is doing something different?
> 
It uses page space, which may incur  the I/O cost
of swapping.

>>can a downstream step take timely action on output
>>from an upstream step?  This is routine design in
>>CMS Pipelines.
>
>Is there no possible z/OS alternative? Are you saying this is how the 
>performance sysprog wants you to do this in z/OS?  You do this in CMS, what is 
>the downside? In z/OS, does it impact CICS, IMS, DB2, MQ and more. 
>
If it hurts, don't do that.  I'm not discrediting alternatives
in some cases.

>>Pipelines cannot run two CMS stages concurrently.  
>
>Which is it? You just said "timely action" which implies multi-tasking instead 
>of waiting for the completion of the previous stage.
>
The "CMS" stage may run a Classic CMS program object.
Those are not designed to support concurrency.  Therefore
Pipelines CMS locks, prevents any concurrent stage.
Multiple REXX and builtin stages may run concurrently.

>> MVS ATTACH does
>>that well, with some restrictions due to the kludge of the alternate DDNAME
>>list.  It should have been possible to make DDNAMEs have task scope
>>optionally, instead of job scope.
>
>That ship sailed back in the 1960's. I wouldn't want to debug DDname reuse.
>
If a Court of Appeals rules against it, must it return to port?

>>ADDRESS ATTCHMVS for compatibility.  But, ironically, that
>>does not support multitasking, at which some people, contrary
>>to your prejudice, are competent.
>
>Since you understand multi-tasking, please tell us when should ADDRESS 
>ATTCHMVS be used instead of ADDRESS LINKMVS.
>
Earlier, you said LINK, not LINKMVS.  LINK supplies a CMS-format PLIST;
LINKMVS and ATTCHMVS supply a CALL-compatible PLIST.  But I
consider ATTCHMVS  a travesty.  It performs ATTACH then WAITs for
completion.  No concurrency.

>There are several people here who easily handle multi-task. But there are 
>equally as many who think they understand it. It's not prejudice when the 
>answers require an understanding the entire audience.
>
There will always be uninformed readers.  Don't let them set the standard.

-- 
gil

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