On 2/10/2016 9:05 AM, R.S. wrote:
W dniu 2016-02-10 o 17:03, Mike Schwab pisze:
On a z14, you won't be able to run OS 2.9 or earlier, or 31 bit Linux.
Not even under z/VM.
Well, I wouldn't call it big problem, especially when compared to
bunch of 31-bit COBOL programs in use. ;-)
BTW: LPAR profile in HMC still offers "ESA/390" Mode. No, there is no
"z/Arch" mode. ESA/390 is the choice for z/OS.
(details are more complcated, but IMHO not relevant here).
You bring up a good point, Radoslaw. This future hardware change has
nothing whatsoever to do with addressing mode.
Today, a machine always IPLs in ESA/390 mode (ARCHLVL=1). Operating
systems that prefer to run in z/Architecture mode (ARCHLVL=2) will
switch to that mode as part of early IPL.
On the new machines (after z13), ESA/390 mode is no longer supported.
IPL will *always* occur in z/Architecture mode so modern operating
systems won't need to explicitly switch modes to function properly. Of
course, IPLs for older operating systems that still require ESA/390 mode
will fail.
As we know, z/Architecture machines can run 24, 31, and 64-bit programs.
That's not going to change.
--
Edward E Jaffe
Phoenix Software International, Inc
831 Parkview Drive North
El Segundo, CA 90245
http://www.phoenixsoftware.com/
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