Another approach (used by qmail and I'm sure other programs) is to use the file system as a database. Process 1 creates a file into a temp directory. Once writi

Another approach (used by qmail and I'm sure other programs) is to use the file system as a database. Process 1 creates a file into a temp directory. Once writing is finished, the file is atomically moved to the working directory where Process 2 deals with it. That wouldn't work so well if you need them to be processed in a specific order, though.