Mark Post said:
Not surprisingly, Sun Microsystems thinks that Linux on IBM mainframes is =
a Bad Idea [tm], largely I suspect because it cuts into their hardware =
sales. As a result, you won't be finding a Sun Java for Linux on System =
z. (It will be interesting if they decide to provide one for OpenSolaris =
on System z at some point.)
A. Harry Williams said:
There are not a lot of alternatives at this point. There is no Sun version
for System z, so your Java developers will have to get over their prejudces.
This is not a System z vs Intel issue, but a Sun JDK vs IBM JDK issue.
Alternatively, you could complain to Sun about their lack of support.
The reason Sun doesn't provide Java for Linux on System z is not because
of our opinion regarding Linux on mainframes, but because IBM is a
licensee of Java technology, and is responsible for Java on its
platforms, not Sun. I imagine that would probably be the case in future
for OpenSolaris on System z unless IBM and Sun contract otherwise. This
is how it has been for a long time and you can see that IBM provides
Java for z/OS, OS/400, and AIX:
http://www-128.ibm.com/developerworks/java/jdk/aix/
http://www.ibm.com/developerworks/java/jdk/index.html
http://www-03.ibm.com/servers/eserver/zseries/software/java/
http://publib.boulder.ibm.com/infocenter/iseries/v5r3/index.jsp?topic=/rzahh/jvm.htm
This is true with other vendors' implementations of Java, so there's no
reason for anyone to feel slighted or singled out:
http://www.bea.com/framework.jsp?CNT=index.htm&FP=/content/products/weblogic/jrockit/
http://developer.apple.com/java/
http://h18012.www1.hp.com/java/
Sun has open-sourced Java - under GPL - so an enterprising soul can do
the port themselves if they want, just as we open-sourced Solaris. Get
the Java source here:
http://www.sun.com/software/opensource/java/getinvolved.jsp Or
download the binary versions we develop, certify and test for the
platforms we support at
http://java.sun.com/javase/6/webnotes/install/system-configurations.html
The point is, Sun provides Java for its own platforms and operating
systems, plus Windows and Linux on Intel/AMD. For us to assume the
substantial cost and effort of providing Java on additional platforms
would be a business decision based on projected revenue to justify
staffing and creating development, QA, distribution and support for
those platforms. Consider the additional skill sets and effort needed
just to develop a z/Arch machine-code generator, or for interaction with
different OSes, and for different C/C++ compilers. Why do any of that
when IBM already provides a JVM?
IMO, there's no more justification (especially for institutions that are
not Sun customers) to "complain to Sun" than there is for non-IBM
customers to complain because IBM didn't port REXX and XEDIT to Solaris.
Or, for that matter, to complain to IBM because IBM's Java isn't
available on CMS.
To the technical issues: there may be some technical differences between
the JVM the developers in the OP are accustomed to, and the ones they
will have available on System z. Command line parameters may differ, and
also behavior related to garbage collection and memory allocation
(including maximum heap sizes possible in different memory models - 31
bit rather than 32 bit may be a consideration). Differences exist even
when multiple JVMs are available on the same OS and hardware platform
(for example, Sun, JRockit, and IBM implementations on Intel have subtle
differences in these areas) To James Melin's comment about using IBM
Java with WebSphere: he's absolutely correct. IBM certifies their app
server with their JVM, so not only does it pass the aquatic fowl test,
it is the IBM-supported configuration.
All the comments are mine and mine alone, all mistakes in the preceding
are also mine, etcetera.
regards, Jeff
PS, as long as I'm posting: I saw Jim Bohnsack at Cornell yesterday
while doing a presentation on Sun xVM (x86 hypervisor based on the
open-source Xen community project), and it was nice to meet him. I added
a "give credit to the pioneers" slide to my presentation that described
the great work done at Cornell, such as the table-driven scheduler
sensitive to guest OS dispatch state, drum to disk page migration, and
minidisk migration. Lest we forget...
--
Jeff Savit
Principal Engineer
Sun Microsystems, Inc. Phone: 732-537-3451 (x63451)
400 Atrium Drive Email: [EMAIL PROTECTED]
Somerset, NJ 08873 http://blogs.sun.com/jsavit/
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