Use this variable to specify how often the runtime should flush pending screen output during file operations. When set to a positive value, the variable indicates the number of file operations to perform between each screen flush. By default, IO_FLUSH_COUNT is set to 20.
For optimal performance, set IO_FLUSH_COUNT to zero (0). When IO_FLUSH_COUNT is set to zero, COBOL file verbs will not automatically flush pending screen output.
To reduce unexpected screen behavior, however, leave this variable at its default setting. The overhead at the default setting is small.