A nagging doubt since my earlier post compelled me to go look at the UCB mapping. It seems that the "bit" is actually a "one-byte count" which makes sense for concurrent RESERVE activity. ===
> Date: Sun, 1 Jul 2012 00:28:04 -0400 > From: [email protected] > Subject: Re: SV: Why is GRS ENQ needed in SMFDUMP program? > To: [email protected] > > In <[email protected]>, on 06/25/2012 > at 09:25 AM, J R <[email protected]> said: > > >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. > > That was the original design, but these days there's an option to > issue an I/O with a reserve CCW at the time that the ENQ SVC issued by > the RESERVE macro obtains the resource. I don't recall what release > added the option. > > -- > Shmuel (Seymour J.) Metz, SysProg and JOAT > Atid/2 <http://patriot.net/~shmuel> > We don't care. We don't have to care, we're Congress. > (S877: The Shut up and Eat Your spam act of 2003) ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
