On Mon, 4 Jan 2010 07:26:15 -0600 "McKown, John" <[email protected]> wrote:
:>> -----Original Message----- :>> From: IBM Mainframe Discussion List :>> [mailto:[email protected]] On Behalf Of Edward Jaffe :>> Sent: Friday, January 01, 2010 10:42 AM :>> To: [email protected] :>> Subject: Re: dead zone :>> Steve Samson <[email protected]> writes: :>> >> The "bar" is a thick one, from 2g to 4g, "sacrificed" to avoid a :>> >> somewhat unlikely compatibility exposure. Undisciplined use of the :>> >> high-order bit in 31-bit addresses could have led to unexpected :>> >> results. The thick bar avoids such a problem. Considering the vast :>> >> magnitude of 64-bit virtual addresses, why should anyone care or do :>> >> anything to circumvent the omitted address range? :>> The z/OS RSM developers introduced functionality to allow Java to :>> acquire storage within the previously "thick" bar for :>> performance reasons. :>Hum, that is very curious to me. But I guess it expands the available/addressable storage without switching from AMODE(31) to AMODE(64) and back. Java is a storage pig. And too much stuff in z/OS still requires AMODE(31) storage (like DCBs et al.) The storage between 2g and 4g is NOT accessible in 31 bit mode. -- Binyamin Dissen <[email protected]> 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 [email protected] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
