It is about executing InfoSphere DataStage jobs and the range of job control options. How we can interact with DataStage from the command line or scripts as discussed in previous 2 posts using dsjob and dsadmin. dsjob even can allow interact with InfoSphere DataStage from other products as well. Even though dsjob and dsadmin are available utilities, getting their information from Server Job Developers Guide is not easily accessible as Parallel Job Developers not frequent readers of this guide.
A common requirement for any Tool is Scheduling of its processes. DataStage comes with a scheduling tool, the Director. Though it provides a all required functionality required by a scheduler like viewing jobs, running jobs and looking at job log results. Under the hood it adds scheduled jobs to the operating system scheduler. The main advantage of it over a third party scheduling tool is the job run options screen that lets you enter job parameter values when you schedule the job.
But Enterprises often want to have one common interface for all their scheduling requirements. It means we need to set job parameters as run the job in some type of scripting language. Jobs are executed by scheduling tools using the dsjob command. Here is an old DSExchange Thread by Ken and Steve explain how this script is used as the main interface between an enterprise scheduler and the single controlling job for a jobstream. This script is responsible for fetching a batch number from a process metadata table and other items.
Vincent McBurney also provided a detailed perspective on how we can Run DataStage from outside DataStage. Vincent also covers Sequence Jobs and Job Control Code in detail.