a short update: linuxcnc development branches:
there are no more major breakage reports outstanding from several folks having tried it, so the dust is settling. There are a few things left to do in the code: since there are several RT kernels supported in the configuration, that currently amounts to different packages for xenomai-user, rt-preempt-user and posix (aka 'simulator'). Since the code differences are quite minor, John and me are working to produce a single 'userland threads' build which supports all of the mentioned styles, and activates them based on autodetection of the underlying kernel (default) or explicity through a startup option. This should make it significantly easier for the build process, and also for trying different kernels with the same configuration (reboot, but no rebuild required). Actually it would be great if we could have a unified build including RTAI, but that is a substantial amount of work, so it's likely to remain with the above. x86 kernels: from the 'it doesnt boot on my machine' perspective it seems we're through the worst with this kernel: http://static.mah.priv.at/public/xenomai-debs/linux-image-3.2.21-xenomai+_0.4_i386.deb . However, John is working with the folks on the Xenomai list to produce debian-style and other 'universal' kernels which likely will be based on a later vanilla kernel (3.5.x). Since these will likely see more exposure than my initial attempt I would rather bet on that option. There is also talk about forward-porting the ipipe patch to 3.8 so with that route it seems to me the 'kernel too old' problem will go away. John probably can give a better picture here. from the latency perspective, I must say the results are still confusing - we have Sam's AMD results which are disappointing, and we have other reports like memleak's which really shine on an AMD (different base version though). We have no figures from the efforts on the Xenomai list yet, but that shouldnt be too long. Also memleak has access to my git kernel repo and I am looking forward to having a build which can be reviewed on other platforms as well. So here it's more about consistent results, rather than instability. In fact I havent seen a kernel oops or crash with the 3.2.21 based kernels in quite a while. ARM work: Several people have been able to get the Beaglebone ubuntu/xenomai setup working as outlined here: http://wiki.linuxcnc.org/cgi-bin/wiki.pl?BeagleboneDevsetup I have updated the kernel and rootfs image a few days ago so the kernel includes ext2/3/4 support compiled in, which should take care of two failure reports I got. Again that xenomai kernel is based on 3.2.21; it works very stable for me but there have been several reports of 'sudden stops'. The BB is a bit sensitive to power fluctuations but it might be more than that. As for that kernel, it works, but it is based on a branch which will see no further development. It supports most of the stuff needed to development; there might be some patches coming from more active BB users than me. Charles has done some great work for a high-speed stepgen on the Beaglebone, and a few folks have reproduced that, but I leave the fanfare to Charles here;) I have done no further work on the Raspberry, I do not consider that platform particularly useful to base work on. RTAI note: I was pointed to this thread recently, which is interesting to read for several reasons: https://mail.rtai.org/pipermail/rtai/2012-December/thread.html "Git repository for RTAI" It does mention a Ubuntu 12.04 RTAI kernel (Shahbaz Youssefi shabbyx at gmail.com Tue Dec 18 11:09:41 CET 2012) - it might be worth following that up, maybe this is an option to get the current builds out of the 10.04 end-of-support-life situation. I would appreciate if somebody more RTAI-aware than me would pick that up. It also touches on the issue how the source repository and collaboration model touches upon a project's success, and that's an interesting read. It looks like the nature of open source communities changes due to for instance the github model, making it easier for the casual contributor, which is a sore spot with the linuxcnc proejct. Something to think about. - Michael ------------------------------------------------------------------------------ Master Java SE, Java EE, Eclipse, Spring, Hibernate, JavaScript, jQuery and much more. Keep your Java skills current with LearnJavaNow - 200+ hours of step-by-step video tutorials by Java experts. SALE $49.99 this month only -- learn more at: http://p.sf.net/sfu/learnmore_122612 _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
