I have recently been looking for a linux OS which has a small
footprint and is capable of running the full Java Runtime Environment
so that I can develop an Electronic Point of Sale System. Ideally the
linux system would boot straight into the Java program once it had
loaded so that the system could only ever be used as a Point of Sale
terminal. At the moment the linux distributions I have seen are very
bloated, especially if you wish to run the JRE within them.

The OS should be able to run well on a 500MHz system with 128Mb RAM
and a <10Gb hard disk. Can you suggest a suitable OS that would run
such a Java application? How would I go about customizing the OS so
that the application loaded on boot and none of the OS was diplayed?

Many thanks,

Niall

This is a very small Linux distro http://www.goosee.com/puppy/.It will
run on the specs you mentioned.The forum here http://linuxforums.com/
may be able to answer your questions.

The core linux kernel is all you need and that is relatively compact
and tiny.  I assume what you'd need to do is create your own custom
init script that the kernel would call upon booting ("init" is is the
first program called by the kernel and is what usually starts up all
the services) that mounts your filesystems and starts the java
program.  That should serve you nicely, and you should easily be able
to run it in your specified requirements.

boot the kernel with the parameter "init=/script.sh" , where
"/script.sh" contains your startup commands.

By default the kernel tries to run /sbin/init by default so you could
replace that -- but be aware of what you're doing!

If you go to distro watch there is one called Damn Small Linux, it has
a foot print of about 50MB. If you go to it's website, it has the
minimum specifications, (can run on 16MB), and can even run in windows
if  needs be. Hope this helps!