Description

   The chdir function changes the default directory. The change can
   be permanent or temporary. Permanent means that the new directory
   remains as the default directory after the image exits. Temporary
   means that on image exit, the default is set to whatever it was
   before the execution of the image.

   There are two ways of making the change permanent:

   o  Call chdir from USER mode with the second argument set to 1.

   o  Call chdir from SUPERVISOR or EXECUTIVE mode, regardless of
      the value of the second argument.

   Otherwise, the change is temporary.