/FCB=address

    Displays all file header control blocks (FCBs) with a nonzero
    DIRINDX for a given volume. If no address is specified, the
    current volume of the current process is used. (See also /FULL.)

    The address specified can also be either a valid volume control
    block (VCB), unit control block (UCB), or window control block
    (WCB) address.