DFO Logical names are recognized by the prefix DFG$

    Table 1 Logical Names

                     Installation
    Logical
    Name             Variant    Purpose

    DFG$DATABASE     Defrag     Equates to the device:[dir]
                     PLUS       specification where the database
                                resides. Also located in this
                                directory are the scheduler log
                                files, which have a name of DFG$_
                                xxxx.LOG, where xxxx is the name of
                                the node on which the scheduler is
                                running.

    DFG$DISK         All        Provided to the EPILOGUE and PROLOGUE
                                command files. It translates to
                                the name of the disk on which DFO
                                currently operates.

    DFG$MAIL_        Defrag     Equates to a file name containing
    ADDRESS          PLUS       a mail distribution list of those
                                who should receive notification when
                                defragmentation processes complete.

    DFG$MESSAGE      All        Equates to
                                SYS$MESSAGE:DFG$MESSAGE.EXE, which
                                is the shareable image containing
                                all the defragmentation-specific
                                messages. This logical is used
                                only if you install the callable
                                interface.

    DFG$SCRIPT       All        Provided to the EPILOGUE and PROLOGUE
                                command files. It translates to the
                                name of the script associated with
                                the DFO process.

    DFG$STATE        All        Provided to the EPILOGUE and PROLOGUE
                                command files. As appropriate to
                                indicate the state of DFO to the
                                command procedure, it translates to
                                either of these strings

                                   PROLOGUE
                                   EPILOGUE

    DFG$STATUS       All        Provided to the EPILOGUE and PROLOGUE
                                command files. It translates to the
                                current status of the DFO process.
                                For the EPILOGUE command file, this
                                status is the final status of the DFO
                                process.

    DFG$ASTLM        All        These logicals affect the associated
    DFG$BIOLM                   process quota of any DFO process
    DFG$BYTLM                   running on the associated node.
    DFG$DIOLM
    DFG$ENQLM
    DFG$FILLM
    DFG$JTQUOTA
    DFG$PGFLQUOTA
    DFG$PRCLM
    DFG$TQELM
    DFG$WSDEFAULT
    DFG$WSEXTENT
    DFG$WSQUOTA

    DFG$TRANSFERSIZE All        The logical, DFG$TRANSFERSIZE, helps
                                you tune the Disk File Optimizer.
                                The definition of this logical allows
                                you to change the amount of data
                                that is transferred at one time. On
                                a volume that has files with large
                                extents, you could wait up to 20
                                minutes while the system transfers
                                these large extents before you could
                                access the file. By defining this
                                logical, you could access this file
                                in less than a minute. This logical
                                changes the impact that the Disk File
                                Optimizer has on applications that
                                are simultaneously accessing the same
                                files.

                                This logical is set to 10,000 blocks
                                by default. You can change it by
                                editing SYS$STARTUP:DFG$STARTUP.COM
                                and then executing the command
                                procedure.

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