How to edit the Booting process on Beagleboard XM

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1

I have posted this in combination with other threads recently with no help.

BACKGROUND:

I am building an audio amplifier with digital effects using Matlab and Simulink. This is a senior design project for UT and we need to have it finished by may 3.

PROBLEM:

I need to be able to access the uboot file or something and edit it to run my audio program automatically after the board boots.

As of right now I have to connect the board to my host computer and run the file but that will not be acceptible because the audio amplifier must be completely stand alone (obviously). I am very new to linux and programming so anyone who can help would be greatly appreciated. I have been looking everywhere for a tutorial that will help me but I can’t find one. I can access the board with putty but I don’t know how to find and edit the boot from there. Also, I plug the sd card into my host computer but I can not edit the uboot image because it is an image, not a text file. PLEASE HELP

Wes

2

There are several ways to run a script at bootup, also depending on
the distribution you use. If you want to run a script as user (not as
root) then you might want to add a crontab job:
# crontab -e
and then add a line:
@reboot /path/to/myscript >> /path/to/my.log 2>&1
For more information see man crontab.

Another way to add a bootscript is to to use sytemctl, see eg
http://stackoverflow.com/questions/11152657/angstrom-start-up-processes-beaglebone

3

Thank you for your response.

I am running simulink on the board which changes the firmware to ubuntu (whatever that is) so the angstrom boot will not do i don’t think. So what I gather I need to do is just type # crontab -e into the command window and @reboot /path/to/myscript >> /path/to/my.log 2>&1 somewhere into whatever shows up (replacing the myscript with whatever my scripts location is)? I’m really sorry but I’m not too good at this.

4

I am running simulink on the board which changes the firmware to ubuntu
(whatever that is) so the angstrom boot will not do i don't think.

Ubuntu (see ubuntu.com ) is another distribution of Linux. IMHO you
are still running Angstrom...

So what
I gather I need to do is just type # crontab -e into the command window and
@reboot /path/to/myscript >> /path/to/my.log 2>&1 somewhere into whatever
shows up (replacing the myscript with whatever my scripts location is)?

Yes!
Maybe you want first to read a bit about cron.
cron - Wikipedia is a quite good overview.
And maybe you start not first with @reboot but with a line like this one:
* * * * * date >> /path/to/my.log 2>&1
This cronjob will write every minute the actual time to my.log

HTH
Dieter

5

Ok, it didn’t seem to work. Here is what I entered

Login: ubuntu
pass: temppwd
and then this came up

ubuntu@rAMPage:~$

so I typed “# crontab -e” and the above line came up again

si I typed "@reboot /home/ubuntu/Combined_Effects

and it says "-bash: @reboot: command not found

so I typed “@reboot /hom/ubuntu/Combined_Effects >> /path/to/my.log 2>&1”

and it says no such file or directery for /path/to/my.log

6

Ok, it didn't seem to work. Here is what I entered

Login: ubuntu
pass: temppwd
and then this came up

ubuntu@rAMPage:~$

so I typed "# crontab -e" and the above line came up again

You have to type
crontab -e
without the #

7

Hey I’m sorry to keep bothering you but my time is running out. I got to crontab and entered in the following:

@reboot /home/ubuntu/Combined_Effects_rrt/MW/Combined_Effects &

and saved it and it still does not work. A guy from mathworks also helped me out with some of it and it still won’t work. I see around the internet that there is something to do with the init tab? Is there anything to this that you know of?

Thanks for all the help

8

Try running the script directly. If that doesn't work, then it's a problem in the script. Type:
     /home/ubuntu/Combined_Effects_rrt/MW/Combined_Effects

Also make sure your cron changes took effect by listing the schedule. You should see your script listed in the schedule. Type the following:
     crontab -l

I don't have a BeagleBoard yet (it was just shipped to me), so I don't know if @boot is supported, or any of its quirks.

Can you find a Linux guru to look over your shoulder when you are doing this? You may be making a very simple beginner's mistake of some sort.

Best of luck....