Raymond,
That was my thought as well.  It will not have a negative impact on older
programs, and will clearly require a change to both the called program, and
the caller.  
Wayne Driscoll
Product Developer
Western Metal Supply
NOTE: All opinions are strictly my own.
  

-----Original Message-----
From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf
Of Raymond Noal
Sent: Thursday, May 12, 2005 6:10 PM
To: [email protected]
Subject: Re: PARM=

Have you ever heard the old adage - "if it ain't broke, .....".

Instead of messing around with the PARM= field, how about adding a new one
like zPARM= (since these are the days of z/OS, z/VM, z/Linux and (soon to
be) z/TPF on our new z/Series processors). Have zPARM= specify a DDNAME,
like, zPARM=ZPARMS, then code a "//ZPARMS DD *" file for the job. Now you
can have 15PB (random number for the sake of the example) of data for your
parameters. 

Maybe 15PB won't be enough, though, have you seen some of the parameters on
an RPM command for Linux or some of the other open system commands?

HITACHI
 DATA SYSTEMS

Raymond E. Noal
Lab Manager, San Diego Facility
Office: (858) 537 - 3268
Cell:   (858) 248 - 1172


-----Original Message-----
From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf
Of Peter Relson
Sent: Thursday, May 12, 2005 2:36 PM
To: [email protected]
Subject: PARM=

We all know and love (well, at least know) that the limitation in JCL for
PARM= is 100 total characters. We are thinking (again) about expanding this,
and would like to hear your thoughts.

Some of the possibilities include
- just extending, in JCL processing, so that the target routine gets what it
does today (halfword length followed by string, only the string would
potentially be >100). This is obviously the nicest from the target routine's
perspective if it can handle the extended length
- a service that the target routine can call to "give me my parameters".
Obviously the target routine would have to change in order to utilize that
service, and likely would have to dual-path for systems that do not have the
service

One choice that proved not feasible was using a second parameter.
Various utilities already take advantage of the "known" structure and pass
additional data as additional parameters.

Some of the potential problems an existing target routine might have with an
extended length parameter are
- It provided an area via DS of 100 characters, "knowing" that the limit was
100, and then did an EX (execute) of an MVC to move the parameter string,
using the length in the halfword. Unfortunately, if the length is (for
example), 256, this would overlay the next 156 bytes
- It did some operation (MVC, TRT, whatever) that is limited to 256
characters which works fine when the limit is 100, but if the routine was
passed 257 characters of data, it might process that as 257 mod 256
characters in some ways.

What do you think?

Peter Relson
z/OS Core Technology Design

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