Thompson, Steve wrote:
You did say dedicated. And it certainly appears to me to be both
dedicated and reserved (by architectural definition).
In the MVS world, if a Problem State program attempts to modify 00000xxx
(where x is 0-512 decimal and regardless of the content of the current
base register) and LAP is on... So it is not truly available (except to
the SCP). Otherwise, as I recall [MVS environments], that page is Key0
non-fetch protected.
[The above is only for non-Z architected machines. I honestly haven't
read the requisite chapters in the new PoOP.]
We were talking about a *reserved* virtual address range (aka a "hole"
or "dead" zone) i.e., one or more pages that are guaranteed to receive
a translation exception because the virtual address(es) will never be
allocated by the operating system. Page zero does not fit that
requirement no matter how hard you squeeze!
--
Edward E Jaffe
Phoenix Software International, Inc
5200 W Century Blvd, Suite 800
Los Angeles, CA 90045
310-338-0400 x318
[EMAIL PROTECTED]
http://www.phoenixsoftware.com/
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