1.umask (0002); /* turn world write access off */

      mkdir ("sys$disk:[.parentdir.childdir]", 0222);
                                 /* turn write access on */

      Parent directory file protection: System:RWD, Owner:RWD,
                                           Group:R, World:R

      The file protection derived from the combination of the mode
      argument and the file protection mask set by umask is (0222)
      & ~(0002), which is 0220. When the parent directory defaults
      are applied to this protection, the protection for the new
      directory becomes:

        File protection:    System:RWD, Owner:RWD, Group:RWD, World:R

    2.umask (0000);

      mkdir ("sys$disk:[.parentdir.childdir]", 0444);
                                 /* turn read access on */

      Parent directory file protection: System:RWD, Owner:RWD,
                                          Group:RWD, World:RWD

      The file protection derived from the combination of the mode
      argument and the file protection mask set by umask is (0444)
      & ~(0000), which is 0444. When the parent directory defaults
      are applied to this protection, the protection for the new
      directory is:

        File protection:    System:RW, Owner:RW, Group:RW, World:RW

      Note that delete access is not inherited.