On Tuesday 21 May 2019 05:43:38 pm andy pugh wrote: > On Tue, 21 May 2019 at 22:17, Chris Morley > <[email protected]> wrote: > > If we make a 2.8 stabilization branch right now then master is open to > > > merge reverse run, python 3 work, state tags etc. > > And hopefully we won't wait three years to release again... > > I think this might be the way to go. Lets get 2.8 frozen now, squash > the (known) bugs and aim to release ASAP. > > Then we open up master to cool new stuff, as we will be less concerned > about breaking it. And then aim to have 2.8.1 (or 2.9) come out some > time this year with reverse-run etc. > (This doesn't actually change much from the point of view of those > using the feature, they will still be on an experimental branch, but > at least it isn't a reversion for them) > > With Wheezy EOL and the current LiveCD not really working at the > moment I think that there is some urgency. > > (As a stopgap I am trying and failing to make a Wheezy / RTAI liveCD > that works, and we have a patch already lined up to switch to > preempt-rt and Stretch for 2.7.14, but that leaves parallel-port users > potentially in trouble)
How much trouble Andy. This stretch install from the testing branch has a maximum jitter of 18.75 u-secs, on a cpu thats probably the worst for IRQ lag that AMD ever sold, a 2.1 GHz quad core phenom, and its best if I could even get it to run prior to this was several hundred u-secs. But with dampers on the motors I might be able to get 20 ipm out of the motors now on the 6040 gantry. Granted, they can move 10x faster with a 7i76D<->5i25 combo now. But what can I carve at 200 ipm? IMO, if parport has a latency penalty, limiting the speed that badly, the beginner using a parport and a $20 Sainsmart breakout, will want to go faster, so he installs a 5i25, then discovers he is quickly out of i/o even useing both ports and a pair of Sainsmart bobs. That will get him going fast enough to make some sheckels with it, all w/o changing the motors. Next up is a firmware change in the 5i25 so he can drive one or even 2 7i76D's. Only then will he have i/o enough to consider machining a tool changer and even control the shop coffee pot. I ran for several years on a 23 u-sec latency AMD 32 mobo, and learned a lot. It can be a good setup for a new bee. So I don't see 19 u-secs to be all that bad given the 200+ u-sec history of this machine. Put this kernel on an atom cpu and I'd expect 5 u-secs. That will tickle motors right well I'd think. Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
