In-line response.
On 08/14/2012 08:58 AM, McKown, John wrote:
Just a guess on my part, but the OP may know that Linux runs natively on many hardware systems:
i386, x86_64, Power, i, and z. He may have been wondering if z/OS could also run on multiple
architectures. Of course, on reason that Linux runs on so many architectures is thanks to GNU's GCC
being ported to so many and the fact that the majority of Linux is written in C. I was always
wondering if IBM could convert z/OS to another architecture by changing the "back end" of
PL/S (or whatever it's called now, I just don't seem to be able to remember, don't flame me,
please) along with an HLASM which take z instructions and "assembles" then into the
equivalent in another architecture.
Even assuming that most of z/OS were written in some higher-level
language, just changing the compiler code generation to do the same data
structure manipulations using machine instructions on a different
architecture wouldn't do much for functionality, because so many of
those data structures manipulated within the guts of the operating
system (e.g., page/segment tables, Program Call tables, PSWs, Control
Registers, channel programs, etc.) are intimately related to the z/OS
architecture and cease to have any meaning outside the context of z/OS
architecture; not to mention that some of the z architecture hardware
instructions invoked within z/OS are exceedingly complex and may have no
simple counterpart in other architectures.
I'm sure parts of Linux having to do with virtual memory, I/O, hardware
control, and hardware context switching have to be completely rewritten
for different hardware architectures as well, but my impression is that
Linux design philosophy has long included multi-platform support and
this constrains the design and to what extent and where hardware
dependences are allowed.
MVS and its successors have never been intended for anything other than
S/360 and its successor architectures, and there are 50 years of a
symbiotic relationship between hardware and software where major
hardware enhancements have been made just to support specific
functionality more efficiently or more securely in MVS or major MVS
subsystems like CICS or DB2; and major enhancements have been added to
MVS just to exploit new hardware features. Those hardware/software
interdependences are so thoroughly diffused throughout z/OS and its
major subsystems that I would suspect attempting to make z/OS run on any
other architecture is unrealistic.
J C Ewing
Along these lines, "mainframe" does not always mean "IBM z" system. There are vendors who consider
an Itanium to be a "mainframe". Personally, I liked whatever it was they ran in Eureka! "If you can't
crawl around inside it, it's not a mainframe!"
--
John McKown
Systems Engineer IV
IT
Administrative Services Group
HealthMarkets(r)
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(817) 255-3225 phone *
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-----Original Message-----
From: IBM Mainframe Discussion List
[mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf Of zMan
Sent: Tuesday, August 14, 2012 8:39 AM
To: IBM-MAIN@LISTSERV.UA.EDU
Subject: Re: X86 server
On Mon, Aug 13, 2012 at 10:01 PM, Jake anderson
<justmainfra...@gmail.com>wrote:
Hi,
Does IBM provides support running Z/OS on X86 ?
Do you mean, "Will IBM provide support for z/OS if you're
running it under
emulation on Intel hardware?", or "Does IBM provide System z
emulation so
you can run z/OS on Intel hardware?" -- those are quite
different, though
the answer turns out to be the same.
If you have legal access to a zPDT, either as a business
partner or via the
Rational offering. then the answer is YES. Otherwise the answer is NO.
Don't take this the wrong way, but with a userid of
"justmainframes", your
questions are pretty ... basic. And lack context. What are you really
trying to do here? What's the goal? You'll get more help if
you explain
yourself a bit more.
--
zMan -- "I've got a mainframe and I'm not afraid to use it"
--
Joel C. Ewing, Bentonville, AR jcew...@acm.org
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