Date:         Fri, 22 Nov 2002 10:01:41 -0000
Reply-To:     CICS List <CICS-L@LISTSERV.UGA.EDU>
Sender:       CICS List <CICS-L@LISTSERV.UGA.EDU>
From:         "Flint, Mike" <Mike.Flint@UK.EXPERIAN.COM>
Subject:      Re: Question About Below and Above
Content-Type: text/plain; charset="ISO-8859-1"

It's called 'The Bar'   (I'm sure there will be plenty of jokes about
systems programmers showing a lot of interest in this area...)

-----Original Message-----
From: Darrell Ahlberg [mailto:dahlberg7@COMCAST.NET]
Sent: 22 November 2002 05:59
To: CICS-L@LISTSERV.UGA.EDU
Subject: Re: Question About Below and Above


I've not heard much discussion about it, but with the advent of 64-bit
addressing and as shops migrate to it, are we going to have another "line"
issue?  I.E. Will be be hearing a lot about the 2-gig line pretty soon?


----- Original Message -----
From: "Tara Debrodt" <tara.debrodt@FIRSTDATA.COM.AU>
To: <CICS-L@LISTSERV.UGA.EDU>
Sent: Thursday, November 21, 2002 6:37 PM
Subject: Re: Question About Below and Above


> John,
> Thank you very much for this note. I found it very interesting, a very
> elegant distinction which I only just realised. It certainly refined
> my understanding of the task location and data location parms. A further
> question arises for me. I am trying to think of a situation where
> I would want to force a program with an addressing mode of 31 to run below
> the line (AMODE31,RMODE24)
> (apart from no storage above the line, which is not a great imperative I
> would think).
> I'd be very interested to hear of anyone doing this and the scenario that
> dictates this solution.
> Regards,
> Tara Debrodt
>
>
>
>
> "Chase, John" <jchase@USSCO.COM>@LISTSERV.UGA.EDU> on 11/22/2002 01:56:58
> AM
>
> Please respond to CICS List <CICS-L@LISTSERV.UGA.EDU>
>
> Sent by:    CICS List <CICS-L@LISTSERV.UGA.EDU>
>
>
> To:    CICS-L@LISTSERV.UGA.EDU
> cc:
> Subject:    Re: Question About Below and Above
>
>
> On Thursday, November 21, 2002 8:18 AM, EXT / B&M CLARK Graham wrote:
> >                 In the CICS performance Guide it says
> >
> > 3.2.3.2.2 LE run time options for AMODE(24) programs
> >
> >
> >                 | The default LE run time options for CICS are (among
> >                 | other things)
> >                 | ALL31(ON) and STACK(ANY). This means that all programs
> > must run above the
> >                 | line (AMODE(31)) in an LE environment.
>
> That last sentence is quite misleading when it says "all programs must RUN
> above the line"  (emphasis added).  That is absolutely untrue.  What IS
> true
> about ALL31(ON) is that all programs must be capable of addressing storage
> above the line (i.e., must be, or be capable of changing to, AMODE31).
> (But
> even that is not strictly true, as of LE 2.8.)  You can easily demonstrate
> that by link-editing an AMODE31 program with RMODE(24) and running it in a
> CICS region with LE option ALL31(ON).  (Be sure to specify DATALOC=ANY in
> the CICS Program definition, and TASKDATALOC=ANY in its Transaction
> definition.)  You will observe the program to be loaded into storage below
> the line, while quite happily addressing its working storage, etc. above
> the
> line.
>
> > To allow AMODE
> >                 | (24)
> > programs to run
> >                 | in an LE environment, ALL31(OFF) and STACK(BELOW) can
> >                 | be specified.
> >                 | However, if you globally change these options so that
> >                 | all programs can use
> >                 | them, a lot of storage will be put below the line,
> >                 | which can cause a
> >                 | short-on-storage condition.
> >
> >
> >                 My interpretation is that if you set ALL31 to OFF, all
> > programs (even AMODE(ANY) programs) will run below the line. Quite happy
> > to accept that I have misunderstood, but my experience of playing with
> this
> > parameter does back this up.
>
> I think you were misled by the wording of the earlier statement when it
> said
> that all programs "must RUN above the line".  (Emphasis added.)  The later
> caveat about ALL31(OFF) above says only that "a lot of STORAGE will be put
> [allocated] below the line," which is quite true.
>
> You wanna do the RCF to get it changed, or do you want me to?  ;-)
>
> AMODE(ANY) programs carry the RMODE(24) attribute, so they will always
load
> and execute below the line.  RMODE(ANY) programs, which *must* be
> AMODE(31),
> will nearly always load and execute above the line, unless insufficient
> storage is available there.
>
>     -jc-


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