Hi all.
Alright. In order to gain a good understand of the issues that have
arisen during the port of Java2 on Linux, I have read over the past
messages regarding technical difficulties in the port. There seem to
be several main ones:
- Linux threads are screwy and the Java2 source (J2S) uses Solaris threads
rather than pthreads. The two don't mix well.
- J2S is written for 64-bit Solaris.
- J2S uses system calls that are incompatible with Linux.
- Memory management is "tough to port".
- AWT is also somehow hard to port.
The first point makes a lot of sense.
I don't know enough to accept the second point. Yes Solaris 7 is a
"64-bit OS", even though it might run on a 32-bit processor. But what
about 2.6 and 2.5? Are those 64-bit OSs too?
For the third point I can only interpret it to mean that J2S does not
use POSIX calls but some non-standard ones for if they use POSIX
calls, they must be the same on Linux if they are implemented.
The fourth point I can't understand at all. It's standard C. C
provides only the malloc/free pair for dynamic memory. I find it hard
to believe that there could be any sort of shared memory usage. I
suppose there could be some use of thread local storage. Of all these,
I can only see possible problems with the latter. Everything else
should just "compile". What's the problem with memory management?
The fifth one I also can't understand. Isn't Java2 built on top of
Motif/X? Aren't X and Motif calls "standardized"?
If anyone can shed some light, it would be great. Please CC a copy to
[EMAIL PROTECTED] directly. I've been trying to subscribe to the
mailing list and I get these success responses from the mailing list
program but I don't get any messages from the list itself.
Thanks.
Andreas Jaeger writes:
> >>>>> Steve Byrne writes:
>
> Steve> [EMAIL PROTECTED] (Nelson Minar) writes:
>
> >> Java hits threads very hard. In particular, the native threads port of
> >> Java stresses the glibc threading framework (and the kernel!) more
> >> than most systems. So you have to contend not just with portability
> >> problems, not just bugs in the Java sources, but bugs and misfeatures
> >> in the Linux implementation too.
>
> Steve> Right. LinuxThreads doesn't completely play well with signals. This
> Steve> causes race conditions. It's messy. We may end up including a (slightly)
> Steve> custom libpthreads with the release to work around these issues.
>
> Jürgen told me already about some of the problems with LinuxThreads.
> Could anyone from the blackdown team come up with a detailed
> explanation what's broken - and what's needed? As I'm one of the
> glibc developers[1] I might try to help get some of these into glibc.
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