The n_retrys job definition parameter instructs AutoSys to restart the job N number of times upon failure.
command: false 1
Job_a's definition tells AutoSys to restart the job up to 2 times if it initially runs to FAILURE. If after 2 retries the job still does not run to SUCCESS, the job will be set to FAILURE (FA) status and an alarm of type MAX_RETRYS will be generated to alert you that the n_retrys have been exceeded for this job.
For more details on job definition parameters like n_retrys please review the Unicenter AutoSys Job Management Reference Guide.