[mpich-discuss] Running an mpi program that needs to access /dev/mem

[Lee, Eibhlin]

In that case there are definitely misleading guides out there. http://www.cyberciti.biz/faq/ubuntu-linux-root-password-default-password/ This implies that sudo bash does log you in as root user. 
Either my second question confused you; it wasn't the right question to ask; or the guide I linked to is completely wrong.
Eibhlin
________________________________________
From: discuss-bounces at mpich.org [discuss-bounces at mpich.org] on behalf of Jeff Hammond [jhammond at alcf.anl.gov]
Sent: 13 June 2013 15:27
To: discuss at mpich.org
Subject: Re: [mpich-discuss] Running an mpi program that needs to access        /dev/mem

No, of course the root environment is not the same as your user
environment.  There are plenty of "intro to Linux" resources online if
you need this kind of information.

If you want your user environment as root, which I don't think is
particularly safe or a good idea, you can set it with "source
~${yourusername}/.${yourshell}rc" where yourusername is $USERNAME when
you are not root and yourshell is $SHELL when you are not root.

The better option is to figure out what environment variables you need
to set in the mpiexec environment that are currently defined in your
user environment and set those manually.

Jeff

On Thu, Jun 13, 2013 at 9:15 AM, Lee, Eibhlin
<eibhlin.lee10 at imperial.ac.uk> wrote:
> Jeff,
> Does that put you into the same environment as sudo bash? Because I have already tried that with no success.
> Eibhlin
> ________________________________________
> From: discuss-bounces at mpich.org [discuss-bounces at mpich.org] on behalf of Jeff Hammond [jhammond at alcf.anl.gov]
> Sent: 13 June 2013 13:58
> To: discuss at mpich.org
> Subject: Re: [mpich-discuss] Running an mpi program that needs to access        /dev/mem
>
> Just su to root instead of using sudo.
>
> Jeff
>
> On Thu, Jun 13, 2013 at 6:56 AM, Lee, Eibhlin
> <eibhlin.lee10 at imperial.ac.uk> wrote:
>> Hello all,
>>
>> I am trying to use two raspberry-pi to sample and then process some data.
>> The first process samples while the second processes and vice versa. To do
>> this I use gpio and also mpich-3.0.4 with the process manager smpd. I have
>> successfully run cpi on both machines (from the master machine). I have also
>> managed to run a similar program but without the MPI, this involved
>> compiling with gcc and when running putting sudo in front of the binary
>> file.
>>
>> When I combine these two processes I get various error messages.
>> For input:
>> mpiexec -phrase cat -machinefile machinefile -n 2 ~/main
>> the error is:
>> Can't open /dev/mem
>> Did you forget to use 'sudo .. ?'
>>
>> For input:
>> sudo mpiexec -phrase cat -machinefile machinefile -n 2 ~/main
>> the error is:
>> sudo: mpiexec: Command not found
>>
>> I therefore put mpiexec into /usr/bin
>>
>> now for input:
>> sudo mpiexec -phrase cat -machinefile machinefile -n 2 ~/main
>> the error is:
>> Can't open /dev/mem
>> Did you forget to use 'sudo .. ?'
>>
>> Does anyone know how I can work around this?
>> Thanks,
>> Eibhlin
>>
>>
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>
>
> --
> Jeff Hammond
> Argonne Leadership Computing Facility
> University of Chicago Computation Institute
> jhammond at alcf.anl.gov / (630) 252-5381
> http://www.linkedin.com/in/jeffhammond
> https://wiki.alcf.anl.gov/parts/index.php/User:Jhammond
> ALCF docs: http://www.alcf.anl.gov/user-guides
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--
Jeff Hammond
Argonne Leadership Computing Facility
University of Chicago Computation Institute
jhammond at alcf.anl.gov / (630) 252-5381
http://www.linkedin.com/in/jeffhammond
https://wiki.alcf.anl.gov/parts/index.php/User:Jhammond
ALCF docs: http://www.alcf.anl.gov/user-guides
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