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Bernese GPS Software Version 5.0 - Bernese GNSS Software

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19. <strong>Bernese</strong> Processing Engine (BPE)<br />

It is the user’s responsibility that the script can be executed on a given machine using<br />

the command defined in the CPU file. In particular the use of the remote-shell (rsh) or<br />

secure-shell (ssh) commands on a UNIX system may need the assistance of the system administrator.<br />

To test if job submission using these commands is possible, the user can type<br />

the simple command “rsh hostname ls” or “ssh hostname ls” respectively. It is important<br />

that the command works in background, too (which means that the authentication in<br />

case of remote-shell or secure-shell must be done without any interaction). We refer to the<br />

corresponding man pages on how to use the remote (or secure) shell utility.<br />

Of course, if the client is to be started on the same machine as the BPE server, no remote<br />

(or secure) shell is necessary. Here is an example of the command that starts the client on<br />

a local machine:<br />

perl --stdout= --stderr= &<br />

The switches “--stdout” and “--stderr” re-direct the standard output and the error<br />

output to the BPE log-file. They are handled by the BPE client and the syntax works on<br />

all (Windows and UNIX) platforms. Of course it is assumed that the Perl interpreter is<br />

correctly installed and accessible through the path where the operating systems searches<br />

for executables. On UNIX systems it is important to ensure that the client is started in<br />

background. This is done by the trailing “&”. On Windows the ampersand is not mandatory.<br />

The string in the column “Speed” in the CPU file defines a group-name of the corresponding<br />

CPU. If this string is specified as the CPU name for a script in the PCF, the script will<br />

run on one of the CPUs of this group only. In contrary to <strong>Version</strong> 4.2 any CPU group<br />

name is allowed (except ANY or IDLE, see Section 19.5). The field “Maxj” contains the<br />

maximum number of jobs allowed to run on the corresponding CPU simultaneously. The<br />

field “Jobs” contains the number of jobs currently running. Since release “09-Mar-2006” it<br />

has no meaning anymore.<br />

The field “Wait” requires an explanation. The BPE server starts a client script on the remote<br />

CPU to run a BPE script. When the client has become “alive” on the remote host it opens<br />

a TCP/IP connection to the server. If the client does not establish the TCP/IP connection<br />

within the time interval (in seconds) specified in the field “Wait” the BPE server will stop<br />

with an error. It may then be assumed that, e.g., the remote host is not alive or the network<br />

connection does not work correctly. A blank field is equivalent to an infinite waiting time.<br />

The number of currently running jobs is counted in the ${U}/WORK environment. At the<br />

time when the BPE server starts a new job it creates a file<br />

${U}/WORK/CPU cpufile/cpu.port pcfname year session PID SUB PID (where cpu is the<br />

nickname of the CPU). The file is again removed by the BPE server if the job has been<br />

finished. The number of existing files starting with a specific CPU name corresponds to the<br />

number of currently running jobs on this CPU.<br />

The option ”Menu>BPE>Reset CPU file” allows to reset the statistics on the currently running<br />

jobs of a CPU control file to zero. This is simply done by removing all files from the<br />

directory ${U}/WORK/CPU cpufile . This is particularly important if a previously executed<br />

BPE server terminated with a fatal error or has been killed. The CPU file may even be<br />

reset without consequences while a BPE is running. Use the reset-button if a BPE seems<br />

to wait indefinitely for an unknown reason.<br />

Page 388 AIUB

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