Subprocesses are special processes that can be called by any other process. These act exactly as subroutines in programming languages, allowing users to reuse existing processes by sharing them to the whole configuration file. They can thus be used to perform redundant operations that may need to be executed numerous times; for instance, archiving a copy of a zipped file received as the input job file, then decompressing it before sending the unzipped version of it back to the calling process .
Whenever a process calls a subprocess, the main process (the caller) will wait for the called subprocess to finish its execution before carrying on with its own. This means the subprocess feature is synchronous with the main process. This also means the calling process actually appends the subprocess to its own workflow.