Cross-platform DOS emulation package
Complete, accurate emulation and more

DOSBox-X 0.83.7 Release Notes

Release Date: November 1, 2020

Please report any issues in our issue tracker.

Also, make sure to check out our Wiki guide.

New in This Version

1. Notable New Features
  • 32-bit and 64-bit x86 dynamic core
    With the new x86 dynamic CPU core for both 32-bit and 64-bit systems, the overall emulation speed for DOS programs is noticeably improved. Set either "core=dynamic" or "core=dynamic_x86" to enable this core.
  • New CPU types to emulate CPU speed
    You can now emulate the speed in terms of CPU cycles for 286-25MHz, 386DX-25MHz, 486DX4-100MHz, 486DX5-133MHz, Pentium-60MHz, Pentium-75MHz, and Pentium-90MHz CPUs.
  • Opus CD audio tracks
    Support for cue sheets with Opus CD-DA tracks is now available, in addition to FLAC, MP3, WAV, OGG Vorbis CD-DA tracks already supported. Use either the menu or IMGMOUNT command to mount them.
  • Full Ctrl+Break handler
    DOSBox-X now supports full Ctrl+C/Ctrl+Break emulation in the DOS shell and DOS applications. You can also send Ctrl+Break as a special key from the "Main" menu.
  • Support for save files and save remarks
    For the save and load state feature, you can now save to your own save files instead of pre-defined save slots. Save remarks can be entered too for both pre-defined save slots and your own save files.
  • Setting the window position at startup
    A new config option "windowposition" (in [sdl] section) is supported to set the window position at startup in the positionX,positionY format.
  • New clipboard copy and paste features
    There are new clipboard functions such as "copy all text on the DOS screen" and "Stop clipboard pasting" in the menu. Moreover, the mouse copy and paste feature is now supported in Linux and macOS SDL2 builds as well.
  • FluidSynth in Windows MinGW builds
    Support for FluidSynth MIDI Synthesizer is now included in the MinGW builds by default just like Visual Studio builds. Set "mididevice=fluidsynth" and a soundfont file (e.g. GeneralUser_GS.sf2) to use it.
  • xBRZ scaler in Visual Studio SDL2 builds
    The xBRZ scaler is now enabled for Visual Studio SDL2 builds just like Visual Studio SDL1 builds. You can enable it either with the setting "scaler=xbrz" or from the menu (from "Video" -> "Scaler").
  • Raw mouse input option for SDL2 builds
    You can enable this option to bypass the operating system's mouse acceleration and sensitivity settings. This works in fullscreen or when the mouse is captured in window mode.
  • Mount multiple disk or CD images from menu
    You can now mount multiple floppy, hard disk or CD images from the "Drive" menu, swappable with "Swap floppy" or "Swap CD". Command-line usage for this is no longer required.
  • Changing text-mode video settings from menu
    It is now possible to change some text-mode related video settings such as the number of rows and columns directly from the menu (from "Video" -> "Text-mode").
  • Display Sound Blaster and MIDI device configurations from menu
    The menu items "Show Sound Blaster configuration" and "Show MIDI device configuration" are added to the "Sound" menu to show the current configurations of the Sound Blaster and MIDI devices.
2. Notable Usability Improvements
  • New website for DOSBox-X Wiki system
    The primary DOSBox-X Wiki (where you find the DOSBox-X user guide) is now located at the following URL, which is hopefully easier to remember:
  • Easier to navigate DOSBox-X default configuration file
    The primary DOSBox-X sample configuration file now contains common config options only, which should make it easier to navigate than before. The full configuration file is also separately available for users who want to use it.
  • Improved Linux Flatpak support
    Initial Linux Flatpak support was added in the previous version. This version improves it to make it work better.
  • New default "Typical" installation for Windows installer
    The "Typical" installation type is added in the Windows installer as the default installation. Unlike the full installation it will not copy all builds to subdirectories in order to make the installation faster.
  • Built-in real parallel port passthrough features in Windows
    The Windows DLL files inpout32.dll (32-bit) and inpoutx64.dll (64-bit) required for the direct parallel port passthrough feature are now included with Windows installer by default.
  • Native dialog box to display messages
    DOSBox-X will now use native Windows/Linux/macOS dialog box to display quit warnings and save state errors.
  • Reorganized some menu items
    Some menu items in the drop-down menus have been renamed or reorganized to make them look better or more clear than before.
  • Improved command-line help messages
    The help messages for the DOSBox-X command-line options are improved, such as adding the new -silent and -socket command-line options.
  • Improved debuging options from Help menu
    The debugging-related functions are now availble from the "Help" menu, including the debugger and more debugging functions which were previously under other menus.
  • Select a special key to send to DOS with the customized shortcut
    You can now select a special key (Alt+Tab, Ctrl+Break, Ctrl+Alt+Del, etc) to be sent from the key defined in the mapper editor. The key can be selected from the "Send special key" menu group in "Main" menu.
  • Shortcuts for copying all screen text and quick launch functions
    The functions "CopyToClipboard" and "QuickRun" are added to the mapper editor so that you can use shortcuts to activate them (default shortcuts: HOST(F11/F12)+A and HOST(F11/F12)+Q respectively).
  • Enable or disable US keyboard layout for PC-98 mode from menu
    You can now force the default US keyboard layout in PC-98 mode from the menu (from "Video" -> "PC-98" -> "Use US keyboard layout") for those who want to use PC-98 mode without a Japanese keyboard.
3. Bugfixes and Other Improvements
There are also many bugfixes and other improvements, including ported recent DOSBox SVN commits. Please see the full changelogs below for more information.

4. Full Changelog In This Version
  • The primary DOSBox-X Wiki is now located at the URL: (Wengier)
  • Implemented the x86 dynamic core for both 32-bit and 64-bit systems by re-porting the code from SVN. Dynamic core now supports either the dynamic_x86 or the dynamic_rec core. The dynamic_x86 core will be used by default for x86 and x86_64 platforms and if "core=dynamic" is set, and Windows 9x can be run in this dynamic core (although at this time may encounter some issue with the S3 driver). You can also explicit specify setting "core=dynamic_x86" or "core=dynamic_rec" for either the dynamic_x86 core or the dynamic_rec core. Also thank joncampbell123 for the 64-bit fix. (Wengier)
  • You can now use your own save file (in addition to save slots! There are now a "Use save file" toggle item and "Browse save file..." for browsing save files on your computer. A config option "savefile" (in [dosbox] section) is added to specify a save file to use at start. (Wengier)
  • Save state feature now allows users to optionally enter remarks when saving a state. A submenu group "Save/load option" is added (under "Capture") where you can toggle menu items "No remark when saving state" (for disabling input of remarks when saving) and "force load state mode". A menu item "Display state information" is added as well to display the information of the saved state. (Wengier)
  • DOSBox-X will now use native dialog box to display quit warnings and save state errors. (Wengier)
  • Changed some DOS error messages (such as "Illegal command" which now reads "Bad command or filename") similar to real DOS systems. (Wengier)
  • ADDKEY and INT2FDBG commands now appear as programs on Z: drive instead of shell commands. (Wengier)
  • Improved the -z (move virtual drive Z:) function of MOUNT command. You can move the virtual drive as many times as you want, and save/load states will work even after you move the Z: drive. (Wengier)
  • Enhanced the config option "freesizecap" to allow the setting "fixed" which is the same as "false", and a new setting "relative" is added, which will be similar to the setting "fixed" but the reported free disk size will also change relative to the change of the free disk size ever since. (Wengier)
  • Added support for Opus CD-DA tracks by porting and cleaning up the source code from other projects. Many thanks to Marty Shepard and kcgen. (Wengier)
  • Support for FluidSynth MIDI Synthesizer is now included in the MinGW builds by default just like Visual Studio builds. Set "mididevice=fluidsynth" and a soundfont file to use it. (Wengier)
  • Enabled xBRZ scaler for Visual Studio SDL2 builds just like Visual Studio SDL1 builds. (Wengier)
  • Added menu item "Show Sound Blaster configuration" under "Sound" menu to show the current information about Sound Blaster, and also menu item "Show MIDI device configuration" (also under "Sound" menu) to show information about the current MIDI device such as the soundfont file in use. (Wengier)
  • Added "Mount multiple disk/CD images" option to the mounting options of the Drive menu to allow users to mount more than one disk/CD images to a drive, swappable from the menu. Also added separators to the Drive submenu to make it look better. (Wengier)
  • Added new CPU types to the "Emulate CPU speed" menu group namely 286-25MHz, 386DX-25MHz, 486DX4-100MHz, 486DX5-133MHz, Pentium-60MHz, Pentium-75MHz, and Pentium-90MHz. Thanks again for the data provided by the user maximus105. (Wengier)
  • You can now select a special key (e.g. Alt+Tab, Ctrl+Break, Ctrl+Alt+Del, etc) to be sent from the key defined in the mapper editor. The key can be selected (Ctrl+Alt+Del by default) from the "Send special key" menu group in "Main" menu. (Wengier)
  • Added full Ctrl+Break emulation at the BIOS and DOS level, updated console emulation to match. The "Pause" mapper shortcut is now moved to HOST[F11/F12]+Pause instead of Ctrl+Pause so that Ctrl+Break can work properly for users, and the function to send the Ctrl+Break key from the menu ("Send special key" under "Main") is added. Also, the PC-98 STOP key now functions the same as the Ctrl+C and Ctrl+Break keys in IBM PC mode.
  • Added functions "CopyToClipboard" and "QuickRun" to the mapper editor so that you can use shortcuts to activate them (default shortcuts: HOST(F11/F12)+A and HOST(F11/F12)+Q respectively), and a default shortcut HOST(F11/F12)+V is added to the clipboard paste function. Meanwhile, FullCore and SimpleCore shortcuts are removed from the mapper. (Wengier)
  • Added two new menu items in the "Shared clipboard functions" menu group under "Main", including "Copy all text on the DOS screen" which will copy all screen text to the clipboard, and "Stop clipboard pasting" which allows user to stop pasting in the middle of pasting long clipboard content. (Wengier)
  • The mouse copy/paste feature is now available for non-Windows systems on SDL2 builds. Also, pasting from the clipboard with a mapped shortcut is also available for Linux/X11 on SDL1 builds. (Wengier)
  • Added "Use US keyboard layout" toggle menu item in the "PC-98" menu group under "Video" to select whether to force the default US keyboard layout in PC-98 mode, same as the "pc-98 force ibm keyboard layout" config option in [pc98] section. Also moved the "PC-98 PIT master clock" options from the "DOS" menu to this menu group. (Wengier)
  • The full dosbox-x.reference.conf file is renamed to dosbox-x.reference.full.conf. The original file dosbox-x.reference.conf now contains common config options instead of all config options. (Wengier)
  • The CONFIG command and Configuration Tool will now save common and modified config options by default. The -all command-line option (or "Save all options to the configuration file" checkbox) will force to save all config options. A new -mod command-line option is added to CONFIG command to save modified config options only, and a new -norem command-line option is added to not write remarks. (Wengier)
  • Updated the Windows installer to default to the "typical" installation. For the full installation start menu items will be added for DOSBox-X builds copied to subdirectories. A new checkbox "Write common config options (instead of all) to the configuration file" is added which when checked will only write common and modified advanced config options to the config file. Furthermore, for both "typical" and "full" installations the Windows installer will now also copies the DLL files inpout32.dll (32-bit) and inpoutx64.dll (64-bit) to the DOSBox-X install directory for use with the direct parallel port passthrough feature. (Wengier)
  • Improved Flatpak support for Linux. (rderooy)
  • Improved message for the -help command-line option, adding for example -silent and -socket command-line options in the help messages. (Wengier)
  • Added -silent command-line option to run DOSBox-X silently (without showing the DOSBox-X window) and then exit after executing AUTOEXEC.BAT. (Wengier)
  • Fixed command-line option -socket not working for the null-modem feature. (Wengier)
  • Fixed issue that aspect ratio not being respected in full-screen mode when a GLSL shader is enabled with an OpenGL output. (Wengier)
  • Fixed toggle in the "Frameskip" menu group did not change when selecting a different option. (Wengier)
  • Fixed shelling from programs may not work when the shell config option is set. (Wengier)
  • The default country setting ("country" option in [config] section]) now defaults to auto-detection if possible, or 81 (Japan) in PC-98 mode. (Wengier)
  • Increased the default maximum DOS files (adjustable from [config] section) from 127 to 200. (Wengier)
  • Improved resetting with LOADLIN program. (Wengier)
  • Improved Gravis Ultrasound (GUS) implementation to make it more accurately represent the GUS DMA state as expected by the running DOS software.
  • The archive attribute will no longer automatically be applied to directories on non-Windows systems. This fixed issue with PLAYMIDI.EXE from Gravis Ultrasound when listing directories. (Wengier)
  • Applied hack to allow the low DMA channel detection in the SB16 DIAGNOSE program to work. (Wengier)
  • The default setting of the clip_paste_speed option has been changed from 20 to 30, which will help prevent lost keystrokes when pasting from the host clipboard for some programs. (Wengier)
  • With Pentium CPU setting (cputype=pentium) DOSBox-X no longer reports FDIV bug by default. An advanced config option "report fdiv bug" is added to report such CPU bug when set to true. (rderooy & Wengier)
  • Added support for the XDG_DATA_HOME environment variable for config directory in Linux. (rderooy)
  • Added support for compiling with pcap for Windows MinGW builds. (Jookia)
  • Added config option "windowposition" (in [sdl] section) to set the window position at startup in the positionX,positionY format. (tomba4)
  • Added config option "raw_mouse_input" (in [sdl] section; SDL2 builds only) to bypass the operating system's mouse acceleration & sensitivity settings. Implemented by NicknineTheEagle.
  • Added config option "startquiet" (in [dos] section) which when set to true will silence the information messages before launching Windows programs to run on the Windows host. A toggle menu item "Quiet mode (no start messages)" is added to the "Windows host applications" menu group in "DOS" menu. (Wengier)
  • The menu "Show details" (under "Main") is renamed to "Show FPS and RT speed in title bar". (Wengier)
  • Add menu group "Text-mode" under "Video" menu to change some text-mode related video settings, such as changing the number of rows and columns. A zip package named TEXTUTIL.ZIP is added to the Z drive that contains various utilities (such as CGA.COM, EGA.COM, 132X25.COM, 132X43.COM) to change current video setting from the command line. Also added a config option "high intensity blinking" which when set will display high intensity background colors instad of blinking foreground text. The menu item "Allow 9-pixel wide fonts" is moved from the menu group "Compatibility" to here. (Wengier)
  • Added "Debugging" menu group under "Help" menu, and moved items from the "Video" Debug and "DOS" Debug menus and the debugger here (debug builds only). Also allowed to hide/show the console or debugger window in Windows debug builds. With the menu item "Console wait on error" checked the Windows console window will wait for the ENTER key before closing itself after an E_EXIT occurs. (Wengier)
  • Updated MPXPLAY to latest version 1.65. (Wengier)
  • Integrated SVN commits (Allofich)
    - r4386: Correct MPU-401 clock-to-host function to operate independently of playing. Fixes hang at exit when playing Roland music in demos by The Phoney Coders. Clamp tempo to valid range.
    - r4384: ICW1 on the PIC clears the Interrupt Mask Register. Fixes Antagony and quite a few demos that expect IRQs to be unmasked.
    - r4382: Refine adlib timers a bit more and make reading the Adlib take a bit more time.
    - r4378: Prevent some possible deadlocks with sti in dynrec core.
    - r4375: Improve compatibility with older Intel chipsets
    - r4374: Add a bit of hack so cycles=max/auto 90% keeps on working inside batch files after r3925.
    - r4371: Fix regression in Clue: Master Detective.
    - r4370: As an adjunct to r4369, make the reference counts of standard device handles equivalent to those of real DOS.
    - r4369: Compatible side-effect behavior of DOS in the file close function.
    - r4368: Improve error codes for some DOS file functions.
    - r4367: Change FPU_FBST to only write 18 decimals instead of the wrongly 19, this makes it possible to switch 64 integers which in turn fixes some rounding issues. (jmarsh)
    - r4282,r4283: Switch to a different way to calculate DBOPL table offsets.
    - r4280: Prevent GenerateDMASound from running with input of 0.
    - r4279: Remove DMA_TRANSFEREND and replace with DMA_MASKED.
    - r4277: Remove cases not needed after r4276
    - r4276: Remove defunct code related to the initial display mode of the system BIOS during video mode changes.
    - r4274: fix externals.
    - r4273: Make frameskip an integer.
    - r4269: Use fabsf when return value is a float. Small warning fix.
    - r4265: Some more cleanups and memleak fixes.
    - r4264: Pick some lowhanging fruit. (some memory leaks and unused variables)
    - r4262: missed one
    - r4261: These actually use float as input.
    - r4258: Rename bios tester to biostest and make it debug only to avoid people trying to load real bioses.
    - r4257: Add simple program that allows you to boot into a bios image for running cpu tester bios.
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See also: Release notes for the previous version (0.83.6)