General advice
The following suggestions are applicable to data access, regardless of the file handler in use:
Sequential files can be created in memory. If you need a temporary sequential file there is no need to create it on disk. You can obtain better performance by creating the file in memory. The syntax to define a memory file is:
INPUT-OUTPUT SECTION.
FILE-CONTROL.
select my-file assign to address memory-area
  ....
WORKING-STORAGE SECTION.
77 memory-area pic x any length.
In thin client and file server environments, avoid setting iscobol.file.lock_manager *, if possible, especially when there are a lot of clients connected simultaneously (e.g. more than 100 clients).
The files that are used very often should reside on a solid-state drive (SSD) or a RAM disk.