Editing DOSBox (section)

==Features==
DOSBox is a [[command-line program]], configured either by a set of command-line arguments or by editing a [[plain text]] configuration file. For ease of use, several graphical [[front end and back end|front end]]s have been developed by the user community.{{Sfn|Loguidice & Barton|2014|p=103}}

While the DOSBox project hopes that one day the emulator will run all programs ever made for the PC, the goal is not yet reached,{{Sfn|Manual|2019|loc=NOTE}} and as of the latest version the primary focus has been on DOS gaming. The basic version does not support [[long filename]]s, most versions of DOS do not support them, and filenames must follow the [[8.3 filename|8.3 name.extension pattern]]: a maximum of 8 characters for the name and up to 3 characters for the [[filename extension|extension]]. Otherwise, filenames will be altered to fit the pattern.<ref name=cuni>{{cite thesis|url=https://is.cuni.cz/webapps/zzp/download/120113877|title=Modular Objective-C Run-Time Library|last=Váša|first=Kryštof|publisher=[[Charles University]]|date=2013|access-date=November 3, 2020|page=84}}</ref><ref name=Plesniarski>{{cite book|url=https://books.google.com/books?id=FsUnlOPIAdYC&pg=PA201|title=MCTS Guide to Microsoft Windows 7 (Exam # 70-680)|last1=Wright|first1=Byron|last2=Plesniarski|first2=Leon|publisher=[[Cengage Learning]]|date=October 4, 2010|access-date=November 3, 2020|page=201|isbn=9781111309770}}</ref>

There are versions available on the DOSBox website that support long filenames, at the cost of possible incompatibility with some older programs.<ref name="CVN">{{cite web|url=https://www.dosbox.com/wiki/SVN_Builds#Enhanced_SVN_builds|title=DOSBox Enhanced SVN builds|publisher=DOSBox|access-date=December 3, 2020}}</ref>
The focus of the vanilla version is on gaming, and features such as support for [[Ctrl-Break]]<ref name=carlos-iii>{{cite thesis|url=https://e-archivo.uc3m.es/bitstream/handle/10016/15584/ProyectoFC_Anibal_Ramirez_Garcia.pdf|title=Diseño e implementación de un Sistema Operativo para fines didácticos|language=es|trans-title=Design and implementation of an Operating System for educational purposes|last=Ramírez García|first=Aníbal|publisher=[[Charles III University of Madrid]]|date=May 2012|access-date=December 4, 2020|page=168|hdl=10016/15584}}</ref> may be missing.<ref name=Virtualization>{{cite book|url=https://books.google.com/books?id=qXw9p1nzb9QC|title=Virtualization: From the Desktop to the Enterprise|last1=Wolf|first1=Chris|last2=Halter|first2=Erick M.|publisher=[[Apress]]|date=November 3, 2006|access-date=December 4, 2020|page=4|isbn=1430200278}}</ref> Some of the alternative versions support features not present in the vanilla version such as [[Advanced Power Management|APM]] power off, direct parallel port passthrough for printing, and support for East Asian characters.<ref name="CVN" /> 
Because DOSBox accesses the host computer's file system, there thus is a risk of DOS malware exploiting the emulator's security vulnerabilities and causing damage to the host machine, although these vulnerabilities continue to be patched with new DOSBox updates.<ref name=Hack.lu>{{cite thesis|url=https://www.abartel.net/static/p/hacklu2019_build_engine.pdf|title=DOS Software Security: Is there Anyone Left to Patch a 25-year old Vulnerability?|last=Bartel|first=Alexandre|publisher=[[Hack.lu]]|date=October 24, 2019|access-date=December 2, 2020|page=1–2, 18}}</ref>

Users can also capture screenshots and record videos of DOS sessions, although a [[codec]] is required to play the videos.<ref name=Kajaani>{{cite thesis|url=https://www.theseus.fi/bitstream/handle/10024/34091/hietala_otto.pdf|title=Developing a Game Engine With SDL|last=Hietala|first=Otto|publisher=[[Kajaani University of Applied Sciences]]|date=April 26, 2011|access-date=November 19, 2020|page=15|id={{URN|NBN|fi:amk-2011053010299}}}}</ref> It is also possible to record [[Yamaha OPL|OPL]] sound card and [[MIDI]] commands, as well as save sound output on a [[WAV]] file.{{Sfn|Manual|2019|loc=5. Special Keys}} Keyboard keys and the buttons of a game controller can be mapped to other keys and combinations thereof.{{Sfn|Manual|2019|loc=7. KeyMapper}}

===OS emulation===
DOSBox is a full-system emulator that provides [[BIOS interrupt call|BIOS interrupts]]<ref>{{cite book |last1=Black|first1=Michael David|last2=Komala|first2=Priyadarshini  |title=Proceedings of the 42nd ACM technical symposium on Computer science education |chapter=A full system x86 simulator for teaching computer organization |publisher=[[Association for Computing Machinery]]|date=March 2011|pages=365–366|doi=10.1145/1953163.1953272|isbn=9781450305006|s2cid=8334945}}</ref> and contains its own internal DOS-like [[Shell (computing)|shell]]. This means that it can be used without owning a license to any real DOS operating system. Most commands that are found in [[COMMAND.COM]] are supported,{{Sfn|Manual|2019|loc=4. Internal Programs}} but many of the more advanced commands found in the latest MS-DOS versions are not.<ref name=Glasgow>{{cite journal|url=https://www.planets-project.eu/docs/reports/Planets_TB6-D1F_PA6-D12_BinaryTranslationAndVirtualisation.pdf|title=Preservation of Dynamic & Interactive Content by use of Binary Translation and Virtualisation – a Methodology for Experimentation|last=Konstantelos|first=Leo|journal=[[Planets Project]]|publisher=[[Humanities Advanced Technology and Information Institute]]|date=July 1, 2010|access-date=December 20, 2020|page=23}}</ref> In addition to its internal shell, it also supports running image files of games and software originally intended to start without any [[operating system]].{{Sfn|Manual|2019|loc=4. Internal Programs}} Besides emulating DOS, users can also run [[Windows 3.0]] and applications designed for it,{{Sfn|Loguidice & Barton|2014|p=241}} as well as versions of Windows within the [[Windows 9x]] family.<ref name=Win9x>{{cite magazine|url=https://www.wired.it/gadget/videogiochi/2019/02/15/migliori-emulatori-per-pc-mac-linux-videogiochi/|title=Videogiochi vintage, i migliori emulatori per pc, Mac e Linux|language=it|trans-title=Vintage video games, the best emulators for PC, Mac and Linux|last=Barbera|first=Diego|magazine=[[Wired (magazine)|Wired]]|date=February 15, 2019|access-date=November 11, 2020}}<br>{{cite web|url=https://www.techradar.com/how-to/how-to-get-the-windows-98-experience-on-todays-pcs/3|title=How to get the Windows 98 experience on today's PCs|last=Drake|first=Nate|work=[[TechRadar]]|date=June 25, 2018|access-date=November 11, 2020|page=3}}</ref>

When the DOSBox application is opened, it automatically [[Mount (computing)|mounts]] to a virtual, permanent{{Sfn|Manual|2019|loc=4. Internal Programs}} <code>Z:</code> drive that stores DOSBox commands and utilities.<ref name=Haines>{{cite book|url=https://books.google.com/books?id=dsEyDwAAQBAJ|title=Beginning Ubuntu for Windows and Mac Users: Start your Journey into Free and Open Source Software|last=Haines|first=Nathan|publisher=[[Apress]]|date=August 25, 2017|access-date=November 9, 2020|page=131|isbn=9781484230008}}</ref> The reasons for the virtual drive are related to security,<ref name=Koldyrkaev>{{cite magazine|url=https://archive.org/details/PC-World_Magazine_2008-01|title=Apple Virtualization|language=ru|last=Koldyrkaev|first=Nikolay|magazine=[[PC World]]|date=January 2008|access-date=December 25, 2020|issue=61|page=36}}</ref> but the user can mount a different drive letter in the emulator to a directory, image file, floppy disk drive, or CD-ROM drive on the host to access its data. A configuration file and its [[AUTOEXEC.BAT|AUTOEXEC]] section can be used to respectively configure DOSBox settings and execute DOS commands at startup.{{Sfn|Manual|2019|loc=4. Internal Programs}}

===Hardware emulation===
DOSBox is capable of running DOS programs that require the [[central processing unit|CPU]] to be in [[real mode]] or [[protected mode]].<ref name="Interview">{{cite interview | subject = Qbix | interviewer = Classic Dos Games | title = Interview with Qbix | url = https://www.classicdosgames.com/interviews/peterveenstra.html | date = 2008-04-30 | access-date = 2009-01-03 | archive-url = https://web.archive.org/web/20200201092643/https://www.classicdosgames.com/interviews/peterveenstra.html | archive-date = February 1, 2020 | url-status = dead}}</ref> Since DOSBox can emulate its CPU by interpretation, the environment it emulates is completely independent of the host CPU.<ref name="Interview" /> On systems which provide the x86, [[ARM architecture|ARM]], or other [[reduced instruction set computer|RISC]] [[instruction set]]s, however, DOSBox can use [[binary translation|dynamic instruction translation]] to accelerate execution.<ref name=Hack.lu/>{{Sfn|Manual|2019|loc=10. How to speed up/slow down DOSBox}} The emulated CPU speed of DOSBox is also manually adjustable by the user to accommodate the speed of the systems for which DOS programs were originally written.<ref name="6fLMS">{{cite web |url=https://www.howtogeek.com/104725/how-to-use-dosbox-to-run-dos-games-and-old-apps/ |last=Hoffman |first=Chris |title=How To Use DOSBox To Run DOS Games and Old Apps |date=2015-10-05 |website=How-To Geek |access-date=2017-02-09}}</ref>

DOSBox uses the [[Simple DirectMedia Layer]] external library to handle graphics, audio, and input devices.<ref name=pc-welt>{{cite web|url=https://www.pcwelt.de/ratgeber/DOS-Box-Spiele-Klassiker-in-Linux-wiederbeleben-1302385.html|title=DOS-Box: Spiele-Klassiker in Linux wiederbeleben|language=de|trans-title=DOSBox: Revive classic games on Linux|last=Wolski|first=David|work=[[PC-Welt]]|date=June 3, 2020|access-date=November 6, 2020}}</ref> Graphically, it can use the [[DirectDraw]] or [[OpenGL]] [[API]]s, and can also use [[bilinear interpolation]] and scale graphics for computers with modern displays.<ref name=PC-Games>{{cite magazine|url=https://www.pcgameshardware.de/Online-Spiele-Thema-121940/Specials/Origin-Access-Die-Gaming-Flatrate-1265561/|url-access=subscription|title=Flatrate-Gaming à la EA|language=de|last=Bikoulis|first=Alexandros|magazine=[[PC Games|PC Games Hardware]]|date=October 2, 2018|access-date=December 8, 2020|pages=112–113}}</ref> Graphical emulation includes [[IBM Monochrome Display Adapter|text mode]], [[Hercules Graphics Card|Hercules]], [[Color Graphics Adapter|CGA]], [[Enhanced Graphics Adapter|EGA]], [[Video Graphics Array|VGA]], [[VESA BIOS Extensions|VESA]], [[S3 Trio|S3 Trio 64]],<ref name=PVW>{{cite report|url=https://www.ideals.illinois.edu/handle/2142/17097|title=Preserving Virtual Worlds Final Report|last1=McDonough|first1=Jerome|last2=Olendorf|first2=Robert|last3=Kirschenbaum|first3=Matthew|last4=Kraus|first4=Kari|last5=Reside|first5=Doug|last6=Donahue|first6=Rachel|last7=Phelps|first7=Andrew|last8=Egert|first8=Christopher|last9=Lowood|first9=Henry|last10=Rojo|first10=Susan|publisher=[[University of Illinois]]|date=August 31, 2010|access-date=November 3, 2020|page=77|hdl=2142/17097}}</ref> and [[Tandy Graphics Adapter|Tandy]].{{Sfn|Manual|2019|loc=3. Command Line Parameters}} Sound emulation includes the [[PC speaker]], [[AdLib]], [[Gravis Ultrasound]], [[Sound Blaster]], [[Covox Speech Thing|Disney Sound Source]], Tandy, and [[MPU-401]]. However, because DOSBox does not come packaged with Gravis Ultrasound drivers, they need to be installed separately for full support.<ref name=Koldyrkaev/>{{Sfn|Manual|2019|loc=2. Start (FAQ)}}

DOSBox can simulate serial [[null modem]]s using the [[Internet protocol suite|TCP/IP]] protocol and [[IPX]] network tunneling, which allows for DOS multiplayer games using one of them to be played over [[local area network]]s or the Internet.<ref name=Castle>{{cite magazine|url=https://archive.org/details/Maximum_PC_0810-web|title=Run All Your Old Games Using DOSBox|last=Castle|first=Alex|magazine=[[Maximum PC]]|date=August 2010|access-date=November 9, 2020|page=67}}</ref> It can also simulate the [[game port|PC joystick port]], with limited options being to emulate one [[joystick]] with four axes and four buttons; one [[gamepad]] with two axes and six buttons; two joysticks each with two axes and two buttons; a [[Thrustmaster]] Flight Control System joystick that has three axes, four buttons, and a [[hat switch]]; and a CH Flightstick with four axes, six buttons that can be pressed only one at a time, and a hat switch. Newer joysticks and gamepads will need to use one of these configurations to function.{{Sfn|Manual|2019|loc=6. Joystick/Gamepad}}<ref name=Gravis-Gamepad>{{cite web|url=https://www.howtogeek.com/672716/how-the-gravis-pc-gamepad-transformed-pc-gaming-in-the-90s/|title=How the Gravis PC GamePad Transformed PC Gaming in the '90s|last=Edwards|first=Benj|work=How-To Geek|date=June 6, 2020|access-date=November 23, 2020}}</ref>