Re: Debian on Pine64 H64B?
On Friday 10 September 2021 10:35:09 Gunnar Wolf wrote:
> Gene Heskett dijo [Fri, Sep 10, 2021 at 08:07:56AM -0400]:
> > > On Fri, Sep 10, 2021 at 09:50:24AM +0200, LinAdmin wrote:
> > > > I have some doubts that debian.net has the same ownership
> > > > than official debian.org?
> > >
> > > RPi images from raspi.debian.net are GPG-signed by Gunnar Wolf's
> > > key (who is Debian Developer), that's good enough for me.
> > >
> > > Reco
> >
> > But will they run my lathe? If they cannot do it safely, with IRQ
> > latency response well under 50 microseconds they are of sub-zero
> > interest to me.
>
> They are not designed to suit you. I guess you want to build your own
> kernels with the RT_PREEMPT enabled,
yes
> and that's not something you will
> get with any of the mainstream Linux distributions.
Then you need to update your testing of currant wintel versions. I would
estimate that IRQ latency today, thanks to the impetus of the Linus rant
a decade back about its poor performance is having an effect on stock
kernels, compared to a decade ago when latencys often ran north of a
millisecnd, the cureent shipping kernels with buster are now doing under
100 microseconds as the output of the linux-rt list get adopted into
shipping kernels. That is its target, to become the default kernel.
> Also, the
> Raspberry is not the right platform for using RT (I'd suggest you look
> at the Beaglebone, as its hardware with separate microcontrollers is
> better suited at real-time tasks - it has less computing power, but is
> better suited for RT tasks -- you will find
> https://beagleboard.org/static/presentations/MakerFaireNY20140920_Usin
>gBeagleBoneRealTimeMicrocontrollers.pdf interesting).
Depends on your point of view I think.
The beaglebone is for little bitty machines with barely enough hardware
to qualify as a cnc driver, a raspi4b can run circles around it while
browsing the web with firefox, I have done it on that pi4b.
Based on what I have learned, I could run any of the other 3 of my now
wintel powered machines on an rpi4 with a mesa 7i90 & friends interface.
But the rpi4, its 5 amp psu, and the full interface with a box to hold
it all would cost almost $400 per machine to convert. If I was starting
from scratch on a new machine the diff in the power bill would pay the
cost diff per machine in 2 years with the diff in power used. The wintel
stuff is hungry, 200+ watts/machine, the pi uses 10 watts to do the same
job, 21 watts leaving the monitor live too.
> Our images' goal is to provide something as close as possible to a
> base, just-installed Debian image, following the RPi culture of having
> installed images. You can build from there.
And I have, using raspbian buster now. I tried a debian net-install at
about 10.4, ran great till I rebooted and the net disappeared. I asked
how to fix it on this list and got told to shuffle off to the main list,
which doesn't support arm stuff, don't bother us.
I'm sorry if the truth hurts the present managements feelings, but there
it is.
With a bit longer view than most, I am hoping that this "new broom" you
represent will fix some of that, and I do think that by this
conversation even happening at all, that it is improving rapidly.
Someday, I'm hoping, as I hope to see equality in my remaining time,
which I'm borrowing with hardware help now, I'll be 87 in about 3 weeks.
> Of course, if you want to do a shipping in the hundreds, thousands or
> further numbers of units, you won't want to use the images we generate
> -- but you might find the vmdb2 scripts we have as a worthy starting
> point for you to customize and build your own images. FWIW, I have a
> script set for the ~10 Raspberries we use at work for driving displays
> with our activities; I only use our "raw" images for testing them.
Thanks Gunnar. I tried to send you a PM 2-3 days back, but it bounced.
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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