[Emc-users] EMC2 on old distros

[<jmk...@at...>]

Hi All:

While prepping for the EMC-2.0.1 release, I decided to try testing EMC2
on the older compile farm slots.  (We automatically test compiles, but 
we don't actually RUN it, since that can't be automated.)

I quickly found out that EMC2 on BDI-2.xx has been broken since at 
least January of this year.  (There were no RTLinux modules on the
module_helper whitelist, but BDI-2.xx uses RTLinux.)  Although it has
been broken for at least 4 months, nobody has complained...  I guess 
that means nobody is using EMC2 on BDI-2.xx.

I was able to fix the RTLinux problem, but then I ran into a problem
with floating point math in kernel space.  FP math in the kernel has
always been tricky.  We had a workaround that involved using a user
space math library with some functions stubbed out, which worked for
quite a while.  But the workaround recently broke due to other changes.

The newer distros don't need the workaround, because RTAI provides a
proper kernel space math library.  But BDI-2.xx and BDI-TNG don't 
have real kernel math support, so right now they don't work even though
they compile.

We have two choices:

1) Fix the workaround.  Not going to be fun.  It is and will always 
be a kluge.  Unfortunately when it breaks it doesn't show up at compile
time, only at runtime, and since the compile farm doesn't actually run 
emc, we won't know if we accidently break it again.

2) Remove the workaround.  This means dropping support for systems
that don't have proper kernel math support.  We would have to drop
support for EMC2 on BDI-2 and BDI-TNG.  BDI-Live rc46 and BDI-4.xx
would still be supported, as would Ubuntu.

So what I want to know is who, if anyone, is running EMC2 on a BDI-2.xx
or BDI-TNG system?  Speak up if you are, if not I'm going to ask the
board to vote on dropping support for those old systems.

Regards,

John Kasunich