I see your point but I think the "conditionality" of a RESERVE macro applies only to the resource as defined by the qname/rname. Presumably, GRS solves this shortcoming. ===
> Date: Mon, 25 Jun 2012 17:11:07 +0300 > From: bdis...@dissensoftware.com > Subject: Re: Why is GRS ENQ needed in SMFDUMP program? > To: IBM-MAIN@listserv.ua.edu > > On Mon, 25 Jun 2012 09:44:08 -0400 J R <jayare...@hotmail.com> wrote: > > :>The ENQ portion of the RESERVE macro goes ahead as usual. > :>The reserve bit in the UCB is only set if the ENQ is successful. > > :>The RESERVE macro implies IO to the device. If there is no IO > :>before the subsequent DEQ, the hardware reserve doesn't need to be issued. > > My issue is that the I/O can be issued and be blocked because the device is > reserved to another system. By issuing a conditional ENQ, one wishes an > indication that the resource is not immediately available so that other > actions can be taken. > > If that is the way it works, so be it, but it seems wrong to me. > > :>> Date: Mon, 25 Jun 2012 16:33:17 +0300 > :>> From: bdis...@dissensoftware.com > :>> Subject: Re: Why is GRS ENQ needed in SMFDUMP program? > :>> To: IBM-MAIN@listserv.ua.edu > :>> > :>> On Mon, 25 Jun 2012 09:25:02 -0400 J R <jayare...@hotmail.com> wrote: > :>> > :>> :>The RESERVE macro did (still does?) not directly do the hardware > reserve. > :>> :>Rather, it set a bit in the UCB to tell the next IO to the unit to > prepend > :>> :>a reserve CCW to the channel program. > :>> > :>> How would that work with a conditional reserve? How can the O/S know if > the > :>> reserve can be satisfied unless the reserve I/O is complete? > > -- > Binyamin Dissen <bdis...@dissensoftware.com> > http://www.dissensoftware.com > > Director, Dissen Software, Bar & Grill - Israel > > > Should you use the mailblocks package and expect a response from me, > you should preauthorize the dissensoftware.com domain. > > I very rarely bother responding to challenge/response systems, > especially those from irresponsible companies. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
