Editing CONFIG.SYS (section)

=== D{{nbnd}}F ===
;{{anchor|DDSCS}} {{mono|1=DDSCS}} {{nobold|(EDR-DOS 7.01.07 only)}} : Configures the relocation of the drive descriptor tables.
;{{anchor|DEBLOCK}} {{mono|1=DEBLOCK}} {{nobold|(DR{{nbh}}DOS 6.0 (1993 update) and higher only)}} : Specifies the memory segment address up to which multi-sector disk data [[deblocking (data storage)|deblocking]] is allowed.
;{{anchor|DEBUG}} {{mono|1=DEBUG}} {{nobold|(DR{{nbh}}DOS 3.31 - 6.0 and 7.02 and higher only<ref name="Paul_1997_OD-A3"/>)}} : Enables internal debugger support.
;{{anchor|DEFAULT}} {{mono|1=DEFAULT}} {{nobold|(PTS-DOS only)}} : Boot manager.
;{{anchor|DEVICE}} {{mono|1=DEVICE}} {{nobold|(DOS 2.0 and DOS Plus 2.1 with FIDDLOAD and DR{{nbh}}DOS 3.31 and higher; OS/2<ref group="nb" name="since2"/><ref group="nb" name="pts"/>)}} : Loads a device driver into memory.
;{{anchor|DEVICEHIGH}} {{mono|1=DEVICEHIGH}} {{nobold|(DOS 5.0 and DR{{nbh}}DOS 6.0 and higher; OS/2<ref group="nb" name="since2"/><ref group="nb" name="pts"/>)}} : Loads a device driver into upper memory. (Same as {{mono|1=HIDEVICE}} in DR{{nbh}}DOS 5.0.)
;{{anchor|DEVINFO}} {{mono|1=DEVINFO}} {{nobold|(OS/2<ref group="nb" name="since2"/> only)}} : Configures country and codepage information for KBD, SCR, LPT1, LPT2, LPT3 devices.
;{{anchor|DISKCACHE}} {{mono|1=DISKCACHE}} {{nobold|(OS/2<ref group="nb" name="since2"/> only, ignored under DR-DOS 7.02 and higher)}} : Configures cache memory sizes.
;{{anchor|DISKETTE}} {{mono|1=DISKETTE}} {{nobold|(PTS-DOS only)}} : Specifies floppy disk compatibility mode.
;{{anchor|DISPLAY}} {{mono|1=DISPLAY}} {{nobold|(PTS-DOS only)}} : Specifies display font.
;{{anchor|DOS}} {{mono|1=DOS}}<ref name="Schneider_1994"/> {{nobold|(DOS 5.0 and DR{{nbh}}DOS 6.0 and higher; OS/2<ref group="nb" name="since2"/><ref group="nb" name="pts"/>)}} : Specifies whether to load DOS into the high memory area and/or use upper memory. (Similar to {{mono|1=HIDOS=ON}} under DR{{nbh}}DOS 5.0.)
;{{anchor|DOSDATA}} {{mono|1=DOSDATA}} {{nobold|(PC&nbsp;DOS 7.0 and higher, FreeDOS, EDR-DOS 7.01.07 and DRMK only)}} : Specifies whether to load DOS tables ({{mono|1=BUFFERS}}, {{mono|1=FCBS}}, {{mono|1=FILES}}, {{mono|1=LASTDRIVE}}, {{mono|1=STACKS}}) into upper memory.
;{{anchor|DOSDIR}} {{mono|1=DOSDIR}} {{nobold|(PTS-DOS only)}} : Specifies alternative path to search for DOS files.
;{{anchor|DPBS}} {{mono|1=DPBS}} {{nobold|(DRMK only)}}<!-- : . -->
;{{anchor|DPATH}} {{mono|1=DPATH}} {{nobold|(OS/2 3.0 and higher only)}} : Specifies the search path for data files.
;{{anchor|DRIVATTR}} {{mono|1=DRIVATTR}} {{nobold|(PTS-DOS only)}} : Specifies physical parameters of disk drives.
;{{anchor|DRIVPARM}} {{mono|1=DRIVPARM}} {{nobold|(DOS 3.2<ref group="nb">apparently not functional in all PC DOS 3.x version</ref> and higher<ref group="nb" name="pts"/>)}} : Define parameters for unrecognized drives.
;{{anchor|DRSWITCH}} {{mono|1=DRSWITCH}} {{nobold|(DR{{nbh}}DOS 7.02 and higher only)}} : See {{mono|1=SWITCH}}.<ref name="Paul_2000_CONFIG"/>
;{{anchor|DUMPPROCESS}} {{mono|1=DUMPPROCESS}} {{nobold|(OS/2 3.0 and higher only)}} : Enables and specifies drive for <code>PDUMP.nnn</code> error logs.
;{{anchor|ECHO}} {{mono|1=ECHO}} {{nobold|(DR{{nbh}}DOS 5.0 and higher, and PTS-DOS and FreeDOS only)}} : Displays a message on screen.
;{{anchor|EECHO}} {{mono|1=EECHO}} {{nobold|(FreeDOS only)}} : Displays a message including ANSI Escape sequences.
;{{anchor|ERREXE}} {{mono|1=ERREXE}} {{nobold|(PTS-DOS only)}} : Specifies if additional checks should be carried out when starting programs.
;{{anchor|ERROR}} {{mono|1=ERROR}} {{nobold|(DR{{nbh}}DOS 6.0 and higher only)}} : Specifies an error / return code to be assumed in the following.
;{{anchor|EXECA20OFF}} {{mono|1=EXECA20OFF}} {{nobold|(PTS-DOS only)}} : Specifies the state of the [[A20 gate]] when starting a program.
;{{anchor|EXIT}} {{mono|1=EXIT}} {{nobold|(DR{{nbh}}DOS 6.0 and higher only)}} : Finishes CONFIG.SYS processing before the end of the file has been reached (except for {{mono|1=SWITCHES}} and {{mono|1=SHELL}} directive processing under some conditions).
;{{anchor|FASTOPEN}} {{mono|1=FASTOPEN}} {{nobold|(DR{{nbh}}DOS 3.31 and higher and PTS-DOS only)}}: Specified the size of the hash table for fast file open operations. Works considerably differently from the external MS-DOS/PC&nbsp;DOS [[FASTOPEN (DOS command)|FASTOPEN]] driver.
;{{anchor|FCBS}} {{mono|1=FCBS}} {{nobold|(DOS 3.0 and DR{{nbh}}DOS 3.31 and higher; OS/2<ref group="nb" name="since2"/><ref group="nb" name="pts"/>)}} : Specifies the number of cached [[File Control Block|FCBs]] that can be opened at once. (Under DR-DOS, {{mono|1=FCBS}} and {{mono|1=FILES}} dynamically share the same internal buffer.)
; {{anchor|FCBSHIGH}} {{mono|1=FCBSHIGH}} {{nobold|(MS-DOS 7.0<ref name="Microsoft_1995_CONFIG"/> and DR-DOS 7.02 and higher only<ref name="Paul_1997_OD-A3"/><ref name="Paul_2000_CONFIG"/>)}} : Same as {{mono|1=FCBS}}, but explicitly loads FCBs into upper memory.
;{{anchor|FILENAME}} {{mono|1=FILENAME}} {{nobold|(PTS-DOS only)}} : Boot manager.
;{{anchor|FILES}} {{mono|1=FILES}} {{nobold|(DOS 2.0 and DR{{nbh}}DOS 3.31 and higher; OS/2<ref group="nb" name="since2"/><ref group="nb" name="pts"/>)}} : Specifies the number of files that can be opened at once.
;{{anchor|FILESHIGH}} {{mono|1=FILESHIGH}} {{nobold|(MS-DOS 7.0<ref name="Microsoft_1995_CONFIG"/> and DR-DOS 7.02 and higher<ref name="Paul_1997_OD-A3"/><ref name="Paul_2000_CONFIG"/> and FreeDOS only)}} : Same as {{mono|1=FILES}}, but explicitly loads file handles into upper memory.
;{{anchor|FORCE}} {{mono|1=FORCE}} {{nobold|(PTS-DOS only)}} : Include execution of specified CONFIG.SYS subsections. See {{mono|1=IGNORE}}.