The job variables concept is designed primarily for the exchange of information between the jobs of a user. With the aid of these variables, so-called job chains or job networks can be set up. Any number of interdependencies between jobs can be mapped onto job variables so that job start, monitoring of progress (job trace), job restart etc. are practically automatic. Job variables can be created, updated and interrogated on program level via the macro interface. This information can likewise be used for job control.
An additional use of job variables within BS2000 is the monitoring of job/program execution in the system. To do this, the user must define a job variable as a monitoring JV in the MONJV operand of the following commands (for more information on job monitoring see "Link names of monitoring job variables").
MONJV operand in job-monitoring commands:
ENTER-JOBENTER-PROCEDUREPRINT-DOCUMENTSET-LOGON-PARAMETERSTRANSFER-FILE(see “openFT” [15])
MONJV operand in program-monitoring commands:
LOAD-EXECUTABLE-PROGRAM(resp.LOAD-PROGRAM)RESTART-PROGRAMSTART-EXECUTABLE-PROGRAM(resp.START-PROGRAM)
Privileged users can define a monitoring job variable in the following commands:
CLEAR-VOLUME(see “SPACEOPT” [16])CREATE-VM(see “VM2000” [17])EXPORT-PUBSETEXTEND-VM-MEMORY(see “VM2000” [17])FORCE-PUBSET-EXPORTIMPORT-PUBSETMODIFY-JOB-OPTIONSREDUCE-VM-MEMORY(see “VM2000” [17])START-SPACEOPT-JOB(see “SPACEOPT” [16])START-SUBSYSTEM
The operating system then assigns fixed, predefined values to this job variable at certain times. These values can be interrogated by the user within a command sequence in order to follow and, if necessary, influence the processing of the job/program.
A monitoring job variable can be used in the following commands to identify a job:
CANCEL-FILE-TRANSFER(see “openFT” [15])CANCEL-JOBCANCEL-PRINT-JOBCHANGE-TASK-PRIORITYCHANGE-TASK-CPU-LIMITFORCE-JOB-CANCELHOLD-JOBHOLD-TASKINFORM-PROGRAMMODIFY-JOBMODIFY-JOB-OPTIONSMODIFY-PRINT-JOB-ATTRIBUTESMOVE-TASK-TO-CATEGORYRESUME-JOBRESUME-PRINT-JOBRESUME-TASKSHOW-JOB-STATUSSHOW-FILE-TRANSFER(see “openFT” [15])SHOW-PRINT-JOB-ATTRIBUTESSHOW-RESOURCE-ALLOCATION
Up to the end of the job to be monitored, the job variable entry contains the note that the job variable has a monitoring function. The job variable entry can then only be changed if the protection is canceled in the MODIFY-JV-ATTRIBUTES command in the MONJV-PROTECTION operand. If protection is deactivated, then the job monitoring job variables cannot be supplied with current values anymore. That is why some components (e.g. JMS) activate protection each time something is accessed.