n is either 1 (true) or 0 (false). The default value is 0.
OpenMode specifies the default read/write mode to use when opening sequential files with the OPEN command. The options are Read-Write (1) or Read (0).
Changing This Parameter
On the Compatibility page of the Management Portal (System Administration > Configuration > Additional Settings > Compatibility), in the OpenMode row, click Edit. Choose a mode, Read (0) or Read-Write (1).
To change this parameter for a single process only (as opposed to instance-wide), use the OpenMode()Opens in a new tab method of the %SYSTEM.ProcessOpens in a new tab class. See the class reference for details.