ODroid as raplacement for Raspberry Pi

rodw wrote:

great!
So you built the patched kernel from the source at kernel.org?
I got a bit distracted and tried the imges here.
sd-card-images.johang.se/boards/odroid_n2.html
only Bookworm and sid work ...   kinda.

There is a bug which breaks network 

Talking about being waay off the mark!
The error reported by apt update was:
Release file for deb.debian/dists/bookworm/InRelease is not valid yet
This was caused because the system datw was set for 10 Jan, about 18 days behind!
So if you venture here, the following steps should sort it.
find your timezone here  en.wikipedia.org/wiki/List_of_tz_database_time_zones
then I left it installing 1800 odd packages after I typed
We'll see if we can get a graphical environment before I go to bed....

rodw wrote:

great!
So you built the patched kernel from the source at kernel.org?
I got a bit distracted and tried the imges here.
sd-card-images.johang.se/boards/odroid_n2.html
only Bookworm and sid work ...   kinda.

There is a bug which breaks network

 
Talking about being waay off the mark!
The error reported by apt update was:
Release file for deb.debian/dists/bookworm/InRelease is not valid yet
This was caused because the system datw was set for 10 Jan, about 18 days behind!
So if you venture here, the following steps should sort it.
find your timezone here  en.wikipedia.org/wiki/List_of_tz_database_time_zones
then

I left it installing 1800 odd packages after I typed
We'll see if we can get a graphical environment before I go to bed....

> This was caused because the system datw was set for 10 Jan, about 18 days behind!

Ah, interesting. Good to know to look out for that.

> We'll see if we can get a graphical environment before I go to bed....

Good luck! For anyone else reading this, definitely don't `apt install ubuntu-desktop` when you want a desktop. It replaced by custom kernel.

My current status is that I've got tobetter's 5.10 RT kernel working on their Ubuntu 22.04 Server. I'm going to rebuild with their 5.15 RT kernel then test latency with latency-histogram. If results are positive I'm going to post my script in a new thread.

its not so much  system latency (which I would expect will be OK) but network latency. To test this you need a mesa network card, let it run linuxcnc  for a while and open another window and type halcmd show param hm2*tmax*
The read and writes are the ones to look at. The results are in timer ticks so if you have a 3.4 gHz CPU, divide by 3400 to get usec (1000 usecs per servo-thread cycle.)

Hmm, if you follow my footsteps. be sure to expand the partition first thing. I ran out of disk space!
BAck to square 1, writing image to HDD cos apt got broken...
I think it is only 2 gB or so by default...

Thanks, I'll try that out.

I am however interested in system latency too. I have a crazy idea of using one of these board computers to do software stepping. I know it's unlikely to work given latency requirements, but at least I'll have fun finding out for sure.