Editing CONFIG.SYS (section)

=== R{{nbnd}}T ===
;{{anchor|REIPL}} {{mono|1=REIPL}} {{nobold|(OS/2 3.0 and higher only)}} : Specifies if system should reboot automatically on errors.
;{{anchor|REM}} {{mono|1=REM}} {{nobold|(DOS 4.0 and DR DOS 3.31 and higher;<ref name="Paul_2004_YESCHAR"/> ignored under PTS-DOS)}} : Allows comments in CONFIG.SYS.
;{{anchor|RESERVEDRIVELETTER}} {{mono|1=RESERVEDRIVELETTER}} {{nobold|(OS/2 3 FixPack 24 and higher only)}} : Specifies a drive letter not to be used up for local block device drivers.
;{{anchor|RESUMECHAR}} {{mono|1=RESUMECHAR}} {{nobold|(DR-DOS 7.02 and higher only)}}: Specifies the default Resume ({{keypress|R}}) character in Yes/No/Resume queries.<ref name="Paul_1997_OD-A3"/><ref name="Paul_2004_YESCHAR"/>)
;{{anchor|RETURN}} {{mono|1=RETURN}} {{nobold|(DR{{nbh}}DOS 6.0 and higher only)}} : Returns nested CONFIG.SYS processing at previous location of {{mono|1=GOSUB}} or {{mono|1=SWITCH}} directive. An optional return code can be given, otherwise 0 is assumed.
;{{anchor|RMSIZE}} {{mono|1=RMSIZE}} {{nobold|(OS/2<ref group="nb" name="since2"/> only, ignored under DR-DOS 7.02 and higher)}} : Defines the real mode memory size.
;{{anchor|RUN}} {{mono|1=RUN}} {{nobold|(OS/2<ref group="nb" name="since2"/> only)}} : Similar to {{mono|1=CALL}}, loads programs in CONFIG.SYS. Similar to {{mono|1=INSTALL}} under DOS and {{mono|1=CALL}} under OS/2, but loads programs in background concurrently.
;{{anchor|SAVENAME}} {{mono|1=SAVENAME}} {{nobold|(PTS-DOS only)}} : Specifies, if the first character of deleted files should be stored in the [[FAT SAVENAME|reserved area]] of directory entries in the [[File Allocation Table|FAT]] file system.
;{{anchor|SCREEN}} {{mono|1=SCREEN}} {{nobold|(FreeDOS and PTS-DOS only)}} : Similar to {{mono|1=VIDEOMODE}} under PTS-DOS, specifies the video mode to be used under FreeDOS. Under PTS-DOS, {{mono|1=SCREEN}} does not specify the video mode but screen access methods.
;{{anchor|SCROLLOCK}} {{mono|1=SCROLLOCK}} {{nobold|(DR-DOS 7.02 and higher only)}} : Specifies whether the keyboard [[Scroll Lock|{{keypress|Scroll Lock}}]] status is turned on or off.<ref name="Paul_1997_OD-A3"/><ref name="Paul_2004_YESCHAR"/>)
;{{anchor|SET}} {{mono|1=SET}} {{nobold|(DOS 6.0 and DR{{nbh}}DOS 6.0 and higher; OS/2<ref group="nb" name="since2"/>)}} : Sets environment variables.
;{{anchor|SHELL}} {{mono|1=SHELL}} {{nobold|(DOS 2.0 and DR{{nbh}}DOS 3.31 and higher; OS/2<ref group="nb" name="since2"/><ref group="nb" name="pts"/>)}} : Loads the command interpreter shell.<ref name="Paul_2004_YESCHAR"/><ref name="Paul_2004_COMMAND"/>
;{{anchor|SHELLHIGH}} {{mono|1=SHELLHIGH}} {{nobold|(DR-DOS 7.02 and higher and PTS-DOS and FreeDOS only)}} : Same as {{mono|1=SHELL}}, but supports an additional {{mono|1=SIZE}} parameter to define the size of the pre-allocation for COMMAND.COM to relocate its resident portion into the HMA (with <code>/MH</code>). Can be useful to avoid HMA fragmentation in conjunction with third-party shells which cannot load into the HMA. SHELLHIGH under PTS-DOS tries to load the shell into UMBs instead.)<ref name="Paul_1997_OD-A3"/><ref name="Paul_2000_CONFIG"/><ref name="4DOS_8.00_HELP"/><ref name="Paul_2004_YESCHAR"/>
;{{anchor|SHIFTSTATE}} {{mono|1=SHIFTSTATE}} {{nobold|(PTS-DOS only)}} : Specifies the state of the keyboard modifiers like Shift Lock, Num Lock, Scroll Lock or Insert mode.
;{{anchor|SHUTDOWN}} {{mono|1=SHUTDOWN}} {{nobold|(PTS-DOS only)}} : Specifies if files should be closed on {{keypress|Ctrl|Alt|Del}}.
;{{anchor|SOFTREBOOT}} {{mono|1=SOFTREBOOT}} {{nobold|(PTS-DOS only)}} : Specifies if POST should be skipped on reboots.
;{{anchor|STACK}} {{mono|1=STACK}} {{nobold|(ignored under DR{{nbh}}DOS 3.31-5.0 and 7.02 and higher only)}} : Compatibility dummy - DR DOS 3.31 - 6.0 were mostly reentrant and had a different stacks layout.
;{{anchor|STACKS}} {{mono|1=STACKS}} {{nobold|(DOS 3.2 and Novell DOS 7 and higher, ignored under DR DOS 6.0 and PTS-DOS)}} : Specifies the number of stacks for hardware interrupts.
;{{anchor|STACKSIZE}} {{mono|1=STACKSIZE}} {{nobold|(Embedded DOS 6-XL only)}} : Default stack size allocated for new threads.
;{{anchor|STACKSHIGH}} {{mono|1=STACKSHIGH}} {{nobold|(MS-DOS 7.0<ref name="Microsoft_1995_CONFIG"/> and DR-DOS 7.02 and higher,<ref name="Paul_1997_OD-A3"/> and FreeDOS only)}} : Same as {{mono|1=STACKS}}, but explicitly loads buffers into upper memory.
;{{anchor|STORAGE}} {{mono|1=STORAGE}} {{nobold|(PTS-DOS only)}} : Boot manager.
;{{anchor|STRING}} {{mono|1=STRING}} {{nobold|(MS-DOS 3.0 only, ignored under DR-DOS 7.02 and higher)}} : Internal use.
;{{anchor|STUBA20}} {{mono|STUBA20}} {{nobold|(PTS-DOS only)}} : Specifies how XMS [[A20 gate]] control should work.
;{{anchor|SUBMENU}} {{mono|1=SUBMENU}} {{nobold|(DOS 6.0 and higher, not DR{{nbh}}DOS, not FreeDOS)}} : Specifies a submenu block. (Can be emulated using {{mono|1=CLS}}, {{mono|1=ECHO}} and {{mono|1=SWITCH}} under DR-DOS.)
;{{anchor|SUPPRESSPOPUPS}} {{mono|1=SUPPRESSPOPUPS}} {{nobold|(OS/2 3.0 and higher only)}} : Specifies a drive where to log error information instead of displaying a textmode popup screen.
;{{anchor|SWAPPATH}} {{mono|1=SWAPPATH}} {{nobold|(OS/2<ref group="nb" name="since2"/> only)}} : Specifies swap file path.
;{{anchor|SWITCH}} {{mono|1=SWITCH}} {{nobold|(DR DOS 6.0 and higher only)}} : Conditionally continues nested CONFIG.SYS processing at one of the specified labels depending on keys pressed, with {{mono|1=RETURN}} returning to old location.<ref name="Paul_1997_OD-A3"/><ref name="Paul_2000_CONFIG"/><ref name="Paul_2004_YESCHAR"/>
;{{anchor|SWITCHAR}} {{mono|1=SWITCHAR}} {{nobold|(DOS 2.0-2.1, DOS Plus 2.1 with FIDDLOAD, DR-DOS 7.02 and higher,<ref name="Paul_1997_OD-A3"/> PTS-DOS, FreeDOS and RxDOS only)}}: Defines the default [[SwitChar]] used by the system (either '/' or '-').<ref name="4DOS_8.00_HELP"/>
;{{anchor|SWITCHES}} {{mono|1=SWITCHES}} {{nobold|(DOS 4.0 and Novell DOS 7 and higher; ignored under PTS-DOS)}} : Specifies special options.<ref name="Paul_2004_YESCHAR"/><ref name="Paul_1997_OD-A3"/>
;{{anchor|SXFAKEHWFPU}} {{mono|1=SXFAKEHWFPU}} {{nobold|(OS/2 Warp 4 FixPak 1 (and higher) only)}} : Specifies if a fix for a FPU rounding bug should be activated or not.
;{{anchor|SYSBOOT}} {{mono|1=SYSBOOT}} {{nobold|(PTS-DOS only)}} : Specifies file name of alternative DOS operating systems to boot.
;{{anchor|SYSGEN}} {{mono|1=SYSGEN}} {{nobold|(PTS-DOS only)}} : Configures the location of the various DOS parts in memory.
;{{anchor|SYSLOAD}} {{mono|1=SYSLOAD}} {{nobold|(PTS-DOS only)}} : Load system from alternative disk area.
;{{anchor|SYSTEMPOOL}} {{mono|1=SYSTEMPOOL}} {{nobold|(Embedded DOS 6-XL only)}} : Size of system memory pool from which the system dynamically allocates for various purposes
;{{anchor|SYSTOUMB}} {{mono|1=SYSTOUMB}} {{nobold|(PTS-DOS only)}} : Specifies if DOS data and code should be loaded into UMBs.
;{{anchor|THREADS}} {{mono|1=THREADS}} {{nobold|(OS/2<ref group="nb" name="since2"/> only)}} : Specifies number of concurrent threads.
;{{anchor|TIMEOUT}} {{mono|1=TIMEOUT}} {{nobold|(DR{{nbh}}DOS 6.0 and higher and PTS-DOS only)}} : Specifies the timeouts in CONFIG.SYS single-stepping and with {{mono|1=SWITCH}}, {{mono|1=GETKEY}} and {{mono|1=?}}, and the default answers for Yes/No queries and {{mono|1=SWITCH}} selections.<ref name="Paul_1997_OD-A3"/><ref name="Paul_2000_CONFIG"/><ref name="Paul_2004_YESCHAR"/> PTS-DOS only supports the timeout value.
;{{anchor|TIMESLICE}} {{mono|1=TIMESLICE}} {{nobold|(OS/2<ref group="nb" name="since2"/> only)}} : Configures minimum and maximum time slices for scheduler.
;{{anchor|TMPEXT}} {{mono|1=TMPEXT}} {{nobold|(PTS-DOS only)}} : Specifies the file extension for temporary files.
;{{anchor|TRACE}} {{mono|1=TRACE}} {{nobold|(DR-DOS 7.02 and higher and PTS-DOS only; OS/2<ref group="nb" name="since2"/>)}} : Globally or locally enables or disables CONFIG.SYS (and AUTOEXEC.BAT) single-stepping execution.<ref name="Paul_2004_YESCHAR"/><ref name="Paul_1997_OD-A3"/> The functionality under OS/2 differs significantly from that under DOS.
;{{anchor|TRACEBUF}} {{mono|1=TRACEBUF}} {{nobold|(OS/2<ref group="nb" name="since2"/> only)}} : Specifies size of {{mono|1=TRACE}} log buffer.
;{{anchor|TRAPDUMP}} {{mono|1=TRAPDUMP}} {{nobold|(OS/2 3.0<!-- 4.0? --> and higher only)}} : Logs detailed error information.