On Mar 29, 2013, at 07:46, Vernooij, CP - SPLXM wrote: > They ARE not. > The reference is elliptical.
> Code has to be written to use PARMDD and will therefore not crash production > applications unexpectedly. > Only the JCL need change. If by "code" you mean load modules, code needn't change. But this is subject to interpretation, and Ed G.'s interpretation is quite different from mine, and we haven't yet access to the reference manuals nor a clarification from such as Peter R. or John Ee. > Modifications to current PARM could crash current code, running well for > decades based on ancient specs/assumptions. > > Kees. > > > -----Original Message----- > From: IBM Mainframe Discussion List [mailto:[email protected]] On > Behalf Of Paul Gilmartin > Sent: Friday, March 29, 2013 14:39 > To: [email protected] > Subject: Re: 32760? (was: PARMDD?) > > On Fri, 29 Mar 2013 09:08:36 -0400, Peter Relson wrote: > >>> I did not find Kevin Kelley's post entirely persuasive. This >>> restriction long antedates 2 Kibyte pages, and the equation 8 x 4096 = >>> 32768 is thus historically irrelevant. >> >> Kevin was not trying to persuade. He was merely stating facts. The >> number of pages is not the relevant part of the information. The >> relevant limitation is the number of bytes that a halfword can support. >> > Don't attach too much significance to Gilmorespeak. I took it that he merely > was not persuaded of the validity of the argument. > >> Aside from the BLKSIZE point, we would not consider a number about >> 32767 (for example 65528) as the limit, for compatibility reasons. >> There are surely programs that use "LH" on the 2-byte length field >> without subsequently clearing the high bytes and then rely on the value >> that would misbehave if they land with a negative number. >> > A horrid example is HLASM. I tried it. > > Dog in the manger. > > Similar arguments could be made (and were in May, 2005) against PARM > 100 > (overrun of traditional sized buffers) and PARM >256 (misbehavior of MVC). > Fortunately, z/OS Core Technology Design did not find them persuasive when > considering the PARM enhancement for z/OS 2.1. -- gil ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
