For QNX 4.x ?

Jeppe Sommer jso at
Thu Jun 17 05:11:21 PDT 1999

Junji OAKI writes:
 > Hi all,
 > I am developing robot controllers using QNX, real time OS for IBM-PC.
 > I need Java VM for controlling multiple robot manipulators
 > from MS-Windows machines via network.
 > Unfortunately, QSSL's Java VM for QNX 4.x is still in beta,
 > so I am very interested in Kaffe VM for QNX 4.x.
 > I have two questions.
 > 1)  Which gcc version is suitable to build Kaffe for QNX 4.x ?


 >     Where can I get the gcc ?

 >     I have QNX 4.25A (or 4.24), Watcom C 10.6 and TCP/IP 4.25 (or 4.24).


 >    Has anyone succeeded in building Kaffe for QNX 4.25A(4.24) ?

Yes, I have had kaffe working for QNX 4.2x at various stages. Right
now I have a partial port of a recent kaffe snapshot (some problem
with exceptions remains to be solved). I have, however, been very busy
doing "real" work. I will hopefully soon be able to release a set of
patches for QNX 4.x

 > 2) QNX is a real time OS.
 >     So, Kaffe VM for QNX 4.x is "Real time Java". Right ?


The current (unreleased) port uses the "jthreads" package which is a
user-level thread package. The java virtual machine runs as a single
QNX process, and the CPU time allocated to this process is allocated
to the java threads by an internal scheduler.   

To me, real time means (in a QNX context) that java threads are
handled by the QNX scheduler, so that priority and scheduling policy
can be controlled for each thread.

Also, an interface to the native QNX message passing primitives would
come in handy, making it possible, e.g, to create a java server thread
with a priority that adapts to the priorities of its current clients
(whether "c" processes or java threads).

Last (but not at all least) kaffe currently has a non-incremental
"stop the world" garbage collector. Until this changes, forget about
real time. 

 > Thanks for information,
 > Junji OAKI

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