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Hi Hsie, re: did you make any changes on squall after approx. 12:45 AM Friday > NO. I did not make any changes in the past few days for ldm and > McIDAS. I do upgrade GEMPAK from 5.10.4 to 5.11.1. OK. I have no good explanation for why McIDAS commands were hanging when run as the user 'hsie' on squall before 12:45 AM. My only guess, given that 'strace' showed the commands to be waiting on a system resource, is that there was not enough shared memory to create the second of two shared memory segments that are supposed to be created when a McIDAS "session" (full or transient) is started. My observation was that the first shared memory segment would get created, but the second would not, but the hanging I observed seemed to be more associated with commands run at session startup waiting for something (the commands EG, EU, and GU are run sequentially at each McIDAS "session" startup). If a shortage of shared memory was, in fact, the cause of the hanging processes then the remedial action would be to increase the amount of shared memory available. This process is described for various operating systems in the Unidata McIDAS-X User's Guide: http://www.unidata.ucar.edu/software/mcidas/current/users_guide/toc.html Chapter 1 - Installing and Configuring McIDAS-X http://www.unidata.ucar.edu/software/mcidas/current/users_guide/InstallingandConfiguringMcIDAS-X.html ... Preparing the Workstation http://www.unidata.ucar.edu/software/mcidas/current/users_guide/PreparingtheWorkstation.html Shared Memory Configuration http://www.unidata.ucar.edu/software/mcidas/current/users_guide/workstation.html For Linux, the process is one of adding a line like the following to /etc/rc.d/rc.local: echo 536870912 > /proc/sys/kernel/shmmax and then rebooting. Please let me know if/when you again run into problems running McIDAS commands on squall. Cheers, Tom **************************************************************************** Unidata User Support UCAR Unidata Program (303) 497-8642 P.O. Box 3000 address@hidden Boulder, CO 80307 ---------------------------------------------------------------------------- Unidata HomePage http://www.unidata.ucar.edu **************************************************************************** Ticket Details =================== Ticket ID: YSZ-272620 Department: Support McIDAS Priority: Normal Status: Closed