DOSBox-X v0.83.9 (2021/01/01) is released. DOSBox-x is a branch of DOSBox. DOSBox emulates an Intel x86 PC, complete with sound, graphics, mouse, joystick, modem, etc., necessary for running many old MS-DOS games that simply cannot be run on modern PCs and operating systems, such as Microsoft Windows XP, Windows Vista, Linux and FreeBSD.

DOSBox-X Changelog:
Physical CD drives are now mountable in SDL2 builds
just like SDL1 builds, so commands like "MOUNT -CD"
should work in both SDL1 and SDL2 builds. Some code
is adopted from the SDL2_CDROM library. (Wengier)
Implemented file locking support for mounting disk
image files so that you cannot mount the same disk
image files in read/write mode at the same time as
this can cause possible disk corruptions. A config
option "locking disk image mount" is added to the
[dosbox] section which when set to false (or if the
user mounts the image files read-only) will bypass
the locking of image files. Also improved the DOS
file locking function, which can be disabled by
setting "share=false" in [dos] section. (Wengier)
Implemented PhysFS support so that you can mount
archives (e.g. ZIP/7Z) as drives in read-only mode,
code is ported from a custom DOSBox fork. The menu
option "Mount an archive file (ZIP/7Z)" is added to
Drive menu to mount archives as Drives. (Wengier)
INT 13h now obeys the "hard drive data rate limit"
setting, using the same disk I/O delay code as
INT 21h file I/O. [Issue #2039]
Linux/X11 SDL1 builds: Combine window move/resize
into one call if possible, and not during window
manager hints, to avoid resize problems with the
XFCE 4.14 platform.
Added menu option "Create blank disk images..."
(under "DOS" menu) to create blank floppy or hard
disk images of a common disk size, including 360KB,
400KB, 720KB, 1.2MB, 1.44MB and 2.88MB for floppy
disk images and 250MB, 520MB, 1GB, 2GB, 4GB and 8GB
for hard disk images. The 1GB option (-t hd_1gig)
is also added to IMGMAKE command. (Wengier)
The Configuration Tool will now be centered within
the DOSBox-X window for a better looking. (Wengier)
Added config option "synchronize time" in [dosbox]
section which when set to true will allow DOSBox-X
to automatically synchronize the date and time with
the host system, unless you manually change date
and/or time. A menu option "Synchronize host date/
time" is added to the DOS menu. The function uses
IRQ0 handler; it will not work in PC-98 mode nor if
the timer isn't running at the standard 18.2Hz tick
rate, as any other rate does not make sense and
will cause only jitter and error. Also fixed two
Demoscene entries sl_fokus and sl_haloo which use
BIOS_TIMER with a faster hardware tick rate.
Added config option "showdetails" which when set to
true enables the menu option "Show FPS and RT speed
in title bar" at start. It is equivalent to -showrt
and -showcycles command-line options. (Wengier)
Improved compatibility with Watcom C++ 2.0 when
long filename (LFN) support is enabled. (Wengier)
Added support for starting DOSBox-X in a specific
display on a multi-screen setup (Windows builds as
well as Linux/macOS SDL2 builds). A config option
"display" is added to the [sdl] section that users
can specify a display for the DOSBox-X window to
start. The option can be combined with the existing
"windowposition" config option to specify the
position on the specified display/screen. (Wengier)
DOSBox-X will now pop up a message box to inform
the user when a Direct3D pixel shader is loaded
from the menu on the Windows platform. (Wengier)
Extended serial (COM) ports from COM1-COM3 to COM1-
COM9 in the [serial] section. The config options
serial4-9 are advanced options. You can optionally
specify base addresses for any serial ports. When
the "file" option is used, you can additionally
specify a program to open the file with "openwith"
option. If the specified program cannot be executed
due to some problem, DOSBox-X will try to start a
program as specified with the "openerror" action,
or it will show an error. For both serial (COM) and
parallel (LPT) ports options, the program commands
can be quoted with double quotes, or with single
quotes if the "squote" option is added. (Wengier)
Extended parallel (LPT) ports from LPT1-LPT3 to
LPT1-LPT9 in the [parallel] section. Config options
lpt4-9 are advanced config options. You can also
optionally specify base addresses and IRQs for
these ports. The parallel1-9 config options are
enhanced to allow the generated files to be started
with the specified action: "openpcl" to start a
program to open the file if the print output is
detected to be PCL; "openps" to start a program if
the print output is detected to be PostScript (PS);
"openwith" to start a program otherwise. If you'd
like to specify parameters then be sure to properly
quote the string(s). Furthermore, if any of the
specified program(s) cannot be executed, DOSBox-X
will try to start a program as specified with the
"openerror" action, or show an error. (Wengier)
Added "openwith" and "openerror" config options to
[printer] section to start the specified program to
open the printer output file. The [printer] section
also accepts "fontdir" option where you can change
the path ("FONTS" by default) where the printer TTF
fonts (including courier.ttf, ocra.ttf, roman.ttf,
sansserif.ttf, script.ttf) are located. If no TTF
font can be found (either from the custom path or
system path) for printing, the internal TTF font
for the TTF output will be used. (Wengier)
Added read-only options to the Drive menu to mount
host folders/drives or image files to the specified
drive letter in read-only mode. (Wengier)
You can now use a single mapper file for both SDL1
and SDL2 versions of DOSBox-X! The new mapper file
will be divided to sections [SDL1] and [SDL2] for
both versions. The mapper file can be specified
with the mapperfile config option, or you can set
the mapperfile_sdl1 and mapperfile_sdl2 config
options to override mapperfile option. (Wengier)
Added -defaultmapper command-line option which will
use default key bindings for the mapper. (Wengier)
The menu functions "Load mapper file", "Quick edit
mode", "Stop clipboard pasting" and "Display state
information" have been added to the key mapper so
that you can now define your own shortcut keys to
activate these functions. (Wengier)
The default shortcuts for the "Copy to clipboard",
"Paste from clipboard", and the "Reset window size"
functions are now Ctrl+F5, Ctrl+F6 and Host(F11/F12)
+BackSpace respectively. (Wengier)
Added ttf.fontbold, ttf.fontital, and ttf.fontboit
config options so that you can specify actual bold
italic, and bold-italic TrueType fonts for use with
the TTF output that will render the bold, italic,
and bold-italic text styles using the actual TTF
fonts (e.g. consolab, consolai, consolaz instead of
consola) instead of making the original TTF font
bold, italic, bold-italic automatically. (Wengier)
DOSBox-X now supports the use of arrow keys (left,
right, up, down, home, end) to select and copy text
to the host clipboard in addition to a mouse button
(subject to the specified key modifier, or use the
QuickEdit function). The arrow keys will move the
selections; press Home key to start the actual text
selection and End key to end text selection and to
copy to the clipboard; press ESC key to cancel text
selection. Set config option "clip_mouse_button" to
"arrows" to enable it, or select it from "Shared
clipboard functions" menu group. (Wengier)
You can now press the key combination Ctrl+Tab in
the shell to see a list of files/directories that
can be completed by the Tab completion. (Wengier)
Added SETCOLOR command to view or change the text-
mode color scheme settings. Also fixed the color
palette for the TTF output. (Wengier)
Separated "TTF options" menu group that contains
TrueType font (TTF) related menu options from the
"Text-mode" menu group in "Video" menu. (Wengier)
The "Show menu bar" option now appears in system
menu of the Windows SDL2 build too. (Wengier)
If a language file fails to load, DOSBox-X will now
show a warning dialog instead of exiting. (Wengier)
The option "clip_key_modifier" now accepts values
like "ctrlalt", "ctrlshift", "altshift". (Wengier)
Fixed 2D texture not showing for 3dfx games in the
Glide passthrough mode. (Wengier)
Fixed the mouse sensitivity menu option (under the
"DOS" menu) not working. (Wengier)
Fixed the color palette problem when switching to
graphic mode from mono mode. (Wengier)
Fixed full-screen TTF output may not fully cover
the background screen in Linux. (Wengier)
Fixed that lines starting with "%" in [autoexec]
section are being ignored. (Wengier)
Fixed issues with building the code with original
MinGW using the ./build-mingw script. (Wengier)
Fixed option "output=ttf" not working properly with
-startui/startmapper command-line option. (Wengier)
When the mouse is captured, the title bar will show
the shortcut to release the mouse. (Wengier)
IMGMOUNT now assumes the ISO type for .GOG/.INS
files (which are equivalent to .CUE/.INS files)
if no type is specified by the user. (Wengier)
Improved the dynamic core including the way its
cache is allocated and to support dual mapping.
The FREECG98.BMP file (for PC-98 mode) is now
rendered based on a unifont_jp TTF font instead
of UnifontFullMediumMono.ttf. (roytam1)
Added support for automatic switching from TTF
output to another output in PC-98 mode, allowing
Windows 3.1 to run in this mode. (Wengier)
Added OPL3Duo support, which passes OPL3 output
to an OPL3Duo Arduino board with a specific
configuration if desired. Set the config option
"oplemu=opl3duoboard" to use it. (josephillips85)