The STATIC keyword indicates that the RPG file control information is kept in static storage; all calls to the subprocedure use the same RPG file control information. The RPG file control information holds its state across calls to the subprocedure. If the file is open when the subprocedure ends, then the file will still be open on the next call to the subprocedure.
When the STATIC keyword is not specified, the RPG file control information is kept in automatic storage; each call to the subprocedure uses its own version of the RPG file control information. The RPG file control information is initialized on every call to the subprocedure. If the file is open when the subprocedure ends, then the file will be closed when the subprocedure ends.