RE: Memory Allocation for JAVA under USS

-----Original Message-----
From: IBM Mainframe Discussion List
[mailto:IBM-MAIN@xxxxxxxxxxx] On Behalf Of Betsy Jeffery
Sent: Tuesday, February 27, 2007 9:12 AM
To: IBM-MAIN@xxxxxxxxxxx
Subject: Memory Allocation for JAVA under USS


I've got a developer just starting to use JAVA 1.4 under USS
(z/OS 1.4 soon
to be z/OS 1.7). I'm wondering what people are using as a
general rule for
TSO initial region size for JAVA developers. I don't like
the idea of 256M
per session - which is what I had to give this guy just to
get through
the "Hello World" program. (I started him with 30MB then
48MB and got
tired of customizing IEFUSI for him and jumped to 256MB so there is
certainly room for tuning). I'm looking for advice on 1)
Java under z/OS
tuning and guesstimates or defaults other shops are giving
Java developers
who access USS via TSO. Environmental variables? I haven't
found one
yet. USS parms? Thanks in advance.

Betsy Jeffery
MGIC

I am the only z/OS Java "developer" around here. And I'm not really. My
question would be why do you even want to try this? I use Netbeans on my
PC for Java development. I can then upload the resulting .jar and/or
class files (binary xfer) to the z/OS system and execute them. I have
done this many times. Of course, you do need to be careful.

Now to get IBM angry at me. I actually downloaded some of the z/OS JVM
jar files along with the CICS .jar files from z/OS to my PC. I then
made them available to Netbeans via the Library Manager in Netbeans. In
particular, the ibmjzos.jar, recjava.jar, and recordio.jar files.

I would guess that many may use the Eclipse based WD4z. This is a more
"seamless" environment for development. You pays for what you gets!

Now, to test, I do a binary ftp of the required .jar or .class file(s).
In order to run them, I actually use a "telnet" (not TN3270/TSO/OMVS)
session. My RACF userid has an OMVS segment with a NOMEMLIMIT set. The
MEMLIMIT in SMF is set at 512M, so I actually get 512M. I have the z/OS
telnet set up so that the TERM variable and the DISPLAY variable are set
up correctly. I also have an X server on my PC, so I can actually run
Java GUI programs on z/OS. When I want to burn CPU like nitrocellulose,
that is.

--
John McKown
Senior Systems Programmer
HealthMarkets
Keeping the Promise of Affordable Coverage
Administrative Services Group
Information Technology

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