> From: "[email protected]" <[email protected]> > To: [email protected] > Date: 08/07/2014 01:17 AM > Subject: Re: WAVV2010 Presentation > Sent by: IBM Mainframe Assembler List <[email protected]> > > I realize the presentation was not z/OS specific - So Yes I am > curious if this technique would be available on z/OS. > > ---------- Original Message ---------- > From: Chuck Arney <[email protected]> > To: [email protected] > Subject: Re: WAVV2010 Presentation > Date: Wed, 6 Aug 2014 08:19:14 -0500 > > Remember that WAVV is a z/VSE, z/VM And LINUX conference. I do know > the author of the presentation and he runs z/VSE. So I'm sure what > you see there applies to z/VSE and not necessarily to z/OS. > > Chuck Arney > Arney Computer Systems > zosdebug.com > > > > On Aug 6, 2014, at 7:48 AM, "[email protected]" <[email protected]> wrote: > > > > I discovered a presentation from 2010 > > WAVV 2010 > > KEY15 vs KEY0 > > Author unknown > > > > This presentation provided some source code which I found intresting.
In general, under z/OS, code which is not part of the z/OS BCP should never be doing a LCTL or LCTLG instruction. So it would be very unwise to do this even if it sometimes seemed to produced the desired results. In particular, the z/OS documentation for the MODESET macro makes it very clear that this would never work under z/OS: ,MODE=PROB, MODE=SUP Specifies that the PSW problem state indicator (bit 15) is to be either turned on (PROB) or turned off (SUP). If the MODESET operation completes with a problem state PSW, the caller?s PSW key mask (PKM) is set according to the following rules: ?The bit matching the resulting PSW key is set on. ?The bit matching key 9 is set on. ?For a task attached with ATTACHX using the KEY=NINE parameter, the bits that were on in the PKM of the ATTACHX issuer are set on. ?All other bits are set off. If the resulting PSW is in supervisor state, the caller?s PKM is unchanged. Jim Mulder z/OS System Test IBM Corp. Poughkeepsie, NY
