Any region size in excess of 16m gives you that amount above the line plus everything that is available below the line. REGION=64M is 64M above and (assuming you have a 10M below the line YBTLRMV) gives you the 10M below as well. Been that way for as long as I remember. This also assumes there are no exits messing with the REGION.
YBTLRMV - Your below the line region may vary <vbg> Rob Schramm On Sun, Jun 19, 2016, 6:17 PM Paul Gilmartin < [email protected]> wrote: > On Sun, 19 Jun 2016 15:32:07 -0400, Peter Relson wrote: > > > >The maximum region size is entertaining, but if you ever granted it, you > >would probably cause the address space to fail. There isn't room for > >x'7FF00000' bytes of user storage above the 16M line (and when you specify > >a region size that big, it applies to the area above 16M), > > > Really? I had expected it would apply to both. What happens if a (legacy) > program explicitly requests 24-bit storage? Does that mean that if I > specify REGION=16385K, I can use that amount above the line *plus* > whatever scraps are available below the line? (I understand I'll never > get 16383K.) > > > On Fri, 17 Jun 2016 11:21:44 -0400, Jim Mulder wrote: > > >> >>For diagnostic purposes, then 4K page at 7FFFF000 is always > >> >>left invalid in z/OS. > >> > > >> That might be due to a requirement of ANSI C that there always be an > address > >> algebraically greater than that of any accessible object, for loop > >> termination conditions. > > > > Not likely. It has been that way since the first release of MVS/XA, > >circa 1982. That was a time when MVS still ruled with arrogance, and it > >would takes some doses of marketplace reality changes a few years later > >before MVS became interested in accommodating C and Unix. > > > So it's fortuitous that the design meets both requirements. Or, > the designers might have had similar motivaions in both cases. > > -- gil > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to [email protected] with the message: INFO IBM-MAIN > -- Rob Schramm The Art of Mainframe, Inc ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
