Bernese GPS Software Version 5.0 - Bernese GNSS Software

19. Bernese Processing Engine (BPE)
It is the user’s responsibility that the script can be executed on a given machine using
the command defined in the CPU file. In particular the use of the remote-shell (rsh) or
secure-shell (ssh) commands on a UNIX system may need the assistance of the system administrator.
To test if job submission using these commands is possible, the user can type
the simple command “rsh hostname ls” or “ssh hostname ls” respectively. It is important
that the command works in background, too (which means that the authentication in
case of remote-shell or secure-shell must be done without any interaction). We refer to the
corresponding man pages on how to use the remote (or secure) shell utility.
Of course, if the client is to be started on the same machine as the BPE server, no remote
(or secure) shell is necessary. Here is an example of the command that starts the client on
a local machine:
perl --stdout= --stderr= &
The switches “--stdout” and “--stderr” re-direct the standard output and the error
output to the BPE log-file. They are handled by the BPE client and the syntax works on
all (Windows and UNIX) platforms. Of course it is assumed that the Perl interpreter is
correctly installed and accessible through the path where the operating systems searches
for executables. On UNIX systems it is important to ensure that the client is started in
background. This is done by the trailing “&”. On Windows the ampersand is not mandatory.
The string in the column “Speed” in the CPU file defines a group-name of the corresponding
CPU. If this string is specified as the CPU name for a script in the PCF, the script will
run on one of the CPUs of this group only. In contrary to Version 4.2 any CPU group
name is allowed (except ANY or IDLE, see Section 19.5). The field “Maxj” contains the
maximum number of jobs allowed to run on the corresponding CPU simultaneously. The
field “Jobs” contains the number of jobs currently running. Since release “09-Mar-2006” it
has no meaning anymore.
The field “Wait” requires an explanation. The BPE server starts a client script on the remote
CPU to run a BPE script. When the client has become “alive” on the remote host it opens
a TCP/IP connection to the server. If the client does not establish the TCP/IP connection
within the time interval (in seconds) specified in the field “Wait” the BPE server will stop
with an error. It may then be assumed that, e.g., the remote host is not alive or the network
connection does not work correctly. A blank field is equivalent to an infinite waiting time.
The number of currently running jobs is counted in the ${U}/WORK environment. At the
time when the BPE server starts a new job it creates a file
${U}/WORK/CPU cpufile/cpu.port pcfname year session PID SUB PID (where cpu is the
nickname of the CPU). The file is again removed by the BPE server if the job has been
finished. The number of existing files starting with a specific CPU name corresponds to the
number of currently running jobs on this CPU.
The option ”Menu>BPE>Reset CPU file” allows to reset the statistics on the currently running
jobs of a CPU control file to zero. This is simply done by removing all files from the
directory ${U}/WORK/CPU cpufile . This is particularly important if a previously executed
BPE server terminated with a fatal error or has been killed. The CPU file may even be
reset without consequences while a BPE is running. Use the reset-button if a BPE seems
to wait indefinitely for an unknown reason.
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