The run-time system for multi-threaded applications needs to handle both multi-threaded and single-threaded applications. As a result, the multi-threaded run-time system incurs many of the synchronization costs that a standard multi-threaded COBOL application would. Further, most of these costs are incurred regardless of whether the application is multi-threaded or single-threaded. Because of this, and in order to enable single-threaded applications to run at maximum speed, Micro Focus provides two separate run-time systems(UNIX only): a multi-threaded run-time system that supports all applications, and a single-threaded run-time system that supports only single-threaded applications. You can choose between these run-time systems either when you run your application or when you link your application.
The files you need to ship with an application will depend in some cases on whether your application has been linked to the single-threaded or multi-threaded run-time system.