21 Jun
2020
21 Jun
'20
12:59 p.m.
On Sunday 21 June 2020 05:36:44 Dr. Nikolaus Klepp wrote:
Anno domini 2020 Sun, 21 Jun 04:39:42 -0400
Gene Heskett scripsit:
But its needed to get the lower latencies that machine control demand.
For the rpi4b I cajoled raspbian out of a src file only, no support
preempt-rt kernel, rebuilt it several times as it defaults to building a
whole bunch of stuff that has never been in the same room with a pi,
then to install it I cherry picked the pi stuff, tarballed it into about
a 30 meg file, and unpacked that over the top of the /booot on the card,
replaceing the raspbian stuff, fixed the hard coded drive identifiers
and configured my network, all in a card reader. That was before I had
the heart attack last fall and spent much of the winter in and out of
the cath-lab at WVU/Ruby in Morgantown, getting stents installed here
and there, not all in my heart, but culminating in a new aortic valve
installed in January, and one of the stents in my ticker clogged up and
had to be replaced 2 weeks back. Being a long term DM-II has caught up
with me, and I'm running out of time at 85, but that pi4 is still
running that kernel and my big lathe quite nicely. The main diff is
that all the overlay stuff that clutters up the debian "/boot" file
system has been moved to a subdir in /boot for the pi's. Gotta be
different stuff.
Armbian works fine on the hardkernel stuff, rock64-pro etc, doesn't work
in the pi's for the same reason. But hardkernel folks simply ignore any
requests for realtime support. Their way or the highway. Them, and the
camel that rode in on them.
That r-pi4b has two bigger ssd's plugged in via usb3 adapters, and I do
all the devel work on them so a 64G sd card only gets write abused by
apt, keeping the rest of the system up to date. I had to get rid of the
swap file on the sd card as it wasn't big enough to build LinuxCNC on a
2G pi, making a swap partition on one of the ssd's, so that write abuse
of the u-sd is removed. Then tiger direct had a sale on rebuilt 650 watt
cyberpower UPS's at $40, w/free ship, looked brand new to me, so it
doesn't even get rebooted by a local power failure since there's a 20kw
nat gas fired generator just outside the back door thats up and carrying
the whole place, AC and all in 5 or 6 seconds. I see notes in the log
that its on standby for 30 secs now and then. Shrug.
Thanks deloptes.
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)
If we desire respect for the law, we must first make the law respectable.
- Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/gene>
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On Sunday 21 June 2020 04:11:05 deloptes wrote:
Hi Gene!
Just this week I tried to get arm64 of devuan running on a RPi3B.
While almost everything worked and it booted really fast (~ 5 sec.
from powerup to userland) I was not quite satisfied. To be more
precise, the official 5.XX kernel did not boot, the official hardware
support for the vidocore is broken etc., so I think arm64 not working
is not a devuan/debian issue but also present upstream. The BSDs work
on the PI4, too, but with the same problems. The armhf/lf work like a
charm. Now I'm running the same version of devuan armlf for RPI1 on
all of my RPIs, that means only keeping one image up to date. Looks
like RPI is entering the same problematic field like C64 vs. C128 :)
Oh, the last RTAI patch I saw was for kernel 3.XX, I think, and
nothing since then. Worked fine. RT-PREEMPT is pestilence on my
systems (not only RPi)
Nik Gene Heskett wrote:
The debian version of u-boot is not compatible with the pi's boot
loader for armhf. Never has been to my knowledge.
The one time I tried the netinstall, which installs grub and an
arm64 kernel, it booted nicely but networking was broken.
Basicly if you want debian on a pi you must use the raspbian flavor,
it Just Works, with the usual putzing with networking of course if
running a host file based network which I am. Which version of tde?
The PB and the DEV (14.1) on raspbian and debian
I rather like its ability to manage multiple
workspaces, and my
current gui on the rpi4, LXDE, does a poor job of that, not
remembering a hard to configure 4 pane setup over a reboot, its
easier to ssh -Y into it several times when building LinuxCNC
.deb's from scratch. From other machines with more comfortable
seating. I use R14.0.8 on two machines here, but not on the
rpi4. It is a hair hard on latency's though, a point where the
pi's can use all the help they can get since there is not a port
of RTAI to the armhf's.
I don't have CNC and can't comment. The kernel is an issue as the
debian kernel did not work (buster) - I am not sure if it now
works though.