Thank you both for the historical perspective, and special thanks to Jim for the additional up-to-date clarification - it now makes much more sense.
Best regards, Dori On Wed, Apr 4, 2018 at 8:44 PM, Jim Mulder <[email protected]> wrote: > SVC Assist has not been used since MVS/ESA SP3.1.0 (30 years ago), > so the SVCASF bit has had no meaning for 30 years. It is on in the > SVC 13 and SVC 26 entries because of some obsolete code in > IEAVNPS5, which should have been deleted. However, this causes > no harm, since the bit is not used for anything. > > Jim Mulder z/OS Diagnosis, Design, Development, Test IBM Corp. > Poughkeepsie NY > > IBM Mainframe Discussion List <[email protected]> wrote on > 04/04/2018 11:33:07 AM: > > > From: Rob Scott <[email protected]> > > To: [email protected] > > Date: 04/04/2018 12:36 PM > > Subject: Re: Explanation about the SVCASF bit ("SVC can be > > assisted") in the SVC table? > > Sent by: IBM Mainframe Discussion List <[email protected]> > > > > "SVC Assist" is a facility that performed some common housekeeping > > operations on behalf of the SVC - for example, copying the information > > stored at the last SVC interruption into the current request block, > > saving general registers, and loading the general registers with > > appropriate values. > > > > It was implemented by opcode x'E503'. > > > > -----Original Message----- > > From: IBM Mainframe Discussion List [mailto:[email protected] > > ] On Behalf Of Dori Polotsky > > Sent: Wednesday, April 4, 2018 10:18 AM > > To: [email protected] > > Subject: Explanation about the SVCASF bit ("SVC can be assisted") in > > the SVC table? > > > > Hello, > > > > Does anyone know the meaning of the SVCASF bit (x'01') of the SVCTP > > byte of the SVC table? > > > > If I am not mistaken, on our system (z/OS 2.2 ADCD) following the > > IPL this bit is off for all SVC's except SVC 13 (ABEND, IEAVTRT2) > > and SVC 26 (LOCATE / CATALOG, IGG026DU). Also, I did not see an > > option to select the value for this bit with SVCUPDTE. > > > > Any insights would be appreciated. > > > > Thank you very much, > > Dori > > > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to [email protected] with the message: INFO IBM-MAIN > -- [image: Model9] Dori Polotsky R&D m: +972-54-4584663 e: [email protected] w: www.model9.io ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
