Pavan, Normally I start smpd when I'm the normal user. This time I did it in root. It then prompted me for a smpd phrase (This happened the first time I ever started it in normal user but the first time it had appeared in root.) The uid=0 now. However, when I try to execute the program now, in root, it just hangs. With no messages at all! I checked and the cpi example does work when in root. Eibhlin ________________________________________ From: Pavan Balaji [[email protected]] Sent: 15 June 2013 17:02 To: [email protected] Cc: Lee, Eibhlin Subject: Re: [mpich-discuss] Running an mpi program that needs to access /dev/mem On 06/14/2013 04:43 PM, Lee, Eibhlin wrote:

sorry when I do run mpiexec id the output is uid=1000(pi) gid=1000(pi) groups=1000(pi),4(adm),20(dialout),24(cdrom),27(sudo),29(audio),44(video),46(plugdev),60(games),100(users),105(netdev),999(input)

This is the crux of the problem. Your application processes are being launched as the regular user (uid=1000) instead of as root (uid=0). I assume this is how you ran the program; can you confirm? /* Login as root */ % su % mpiexec [whatever_options] id -- Pavan -- Pavan Balaji http://www.mcs.anl.gov/~balaji