Re: Switching to Java on OS/400 - got a few questions. -- JAVA400-L

StokesP@xxxxxxxxxxxxxxxx wrote:

* What is the resource usage of Java programs
under OS/400?  How can I tell for myself?  It is
very important that we can determine accurately if this is a feasible

path.


I'd be careful on that one. Give it a go and do a profile / load test to
see if AS400's a suitable path - if it meets your requirements fine, else
compare the same tests to other platforms to see if there's something
specific to AS400 implementations that's causing an issue. If you can't
test because you havn't written it yet, do you really want to lock yourself

down 1 route

Our problem here is that it is a bit difficult to measure that, and thelocal gurus came up with a command that displays the current cpu usage(similar to top under Unix, or Performance monitor under Windows). Iwould therefore like to hear if there is something like cpu/memory usage(perhaps for billing for machine time) or a "many snapshots over timewhich can then be summarized" tool (like sar under unix), which couldprovide better numbers?

I've never found Java applications to be resource-intensive on OS/400.
Of course a badly written application could cause problems.


Generally I'd agree. I've only seen 1 instance where there was a big
difference - even with recommended upgrades (v. expensive ones!! to an
already top of the range AS400), the AS400 still couldn't touch an 5k
(euro) dual xeon running Tomcat / WS. Eventual recommendation was we stay
with Xeon for app server level software because IBM couldn't fully fix an
AS400 / Java specific implementation issue.

The primary reason for considering this is to get better bandwith fromJava to the AS/400 environment, plus a simpler machine configuration forour customers. The stability of the OS/400 platform is also an issue here.

(Just for those interested, the SANOS project provides a minimalistickernel which can run the Windows JVM. This means that there is nosurrounding Windows environment which needs to be maintained).