I was thinking 64 bit Java uses the addresses from 2G to 3-8G for its storage. That allows it to use a 32 bit pointer that is shifted 3 bits to create the actual address for items, instead of a 64 direct address.
On Mon, Jun 20, 2016 at 9:50 AM, Steve Smith <[email protected]> wrote: > It's the bar! Only 4KB thick, a big improvement over what I originally > called* the bar from x'80000000' through x'FFFFFFFF'. That one however, is > now available for certain uses, although I would avoid it for the same > reasons it was originally black-listed. > > *In no way is this a claim I have naming rights. > > On Fri, Jun 17, 2016 at 12:27 PM, Walt Farrell <[email protected]> > wrote: > >> On Fri, 17 Jun 2016 11:21:44 -0400, Jim Mulder <[email protected]> wrote: >> >> >> >>For diagnostic purposes, then 4K page at 7FFFF000 is always >> >> >>left invalid in z/OS. >> >> > >> >> >That makes the highest numbered, accessible byte to be at address >> >x'7FFFEFFF' >> >> > >> >> 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. >> >> In any case, "ANSI" C didn't exist until (I think) 1989, though the >> standardization effort began in 1983. So the technique is certainly older >> than ANSI C, and not related to it. >> >> -- >> Walt >> >> ---------------------------------------------------------------------- >> For IBM-MAIN subscribe / signoff / archive access instructions, >> send email to [email protected] with the message: INFO IBM-MAIN >> > > > > -- > sas > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to [email protected] with the message: INFO IBM-MAIN -- Mike A Schwab, Springfield IL USA Where do Forest Rangers go to get away from it all? ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
