The effective working mode determines your ability to compile and run 32- and 64-bit applications. Using the effective working mode in conjunction with the generic cob and cobrun commands has the same effect as using one of the bit-specific commands (for example, cob32 or cobrun64).
The cobmode utility enables you to set the global effective working mode, which affects all users that currently point the $COBDIR variable at the same location. Local effective working mode, which is set using the COBMODE environment variable, only affects your current session. If both modes are set, the local effective working mode is used.
The cobmode utility, and the need to set the effective working mode, is only available if your system is capable of developing or running 64-bit applications. If it is capable and the effective working mode is not set, effective working mode defaults to 64-bit.