INT 2F U - NETWORK REDIRECTOR - CHDIR
        AX = 1105h
        SS = DOS DS
        SDA first filename pointer -> fully-qualified directory name
        SDA CDS pointer -> current directory structure for drive with dir
Return: CF set on error
            AX = DOS error code (see INT 21/AH=59h)
        CF clear if successful
            CDS updated with new path
Notes:  called by DOS 3.1+ kernel
        directory string in CDS should not have a terminating backslash unless
          the current directory is the root
SeeAlso: AX=1103h,INT 21/AH=3Bh,INT 21/AH=60h