Extremely basic initial port, only exists as sources.

https://github.com/rickgaiser/bricks-os

Whether these emulators support operating systems for these consoles is unknown; it must be looked into further. Consoles without meaningful OSes are not included.

https://www.zophar.net/consoles/dreamcast.html

https://dcemulation.org/index.php?title=Emulators

Atari 2600 – Stella, dcs2600

Atari Lynx – Atari Lynx MESS, HandyDC

Bandai WonderSwan (Color) – Oswan DC

Coleco ColecoVision – ColEm, CrabEmu

NEC TurboGrafx-16 – HuCast, Dream Engine, PCECast

Nintendo 64 – DaedalusDC, DCNin64

https://www.youtube.com/watch?v=1eEUmZtRFME https://www.dcemu.co.uk/vbulletin/threads/83587-DaedalusDC-released-N64-Emulator-for-the-Dreamcast-(2-Versions) https://web.archive.org/web/20120617083208/http://www.maturion.de/dreamcast/DaedalusDC.rar

Nintendo Entertainment System – NesterDC SE, FrNES, gleam!, TuxNES-DC, DarcDC, FCE, crab

Super Nintendo Entertainment System – DreamSNES, NGine 9x, Sintendo, SuperFamicast, CATSF

Nintendo Game Boy/Color – PlutoBoy git, Boob!boy, Gnuboy/DC

https://github.com/RossMeikleham/PlutoBoy

Nintendo Game Boy Advance – gpSPDC 0.9 Alpha, Visual Troy Advance

Nintendo Pokémon Mini - PokeMini

Sega Genesis – DCGenerator, Genesis Plus SDL, Gens4All, ljsdcgen

Sega Master System – DreamSMS, SMEG, SMS Plus, SMS Plus (alternative)

Sega Saturn – Yabause (WTF????)

https://yabause.org/download/

https://dcemulation.org/index.php?title=Yabause

Sony PlayStation 1 – PCSXDC, PCSX4ALL, bleemcast!

https://www.zophar.net/consoles/dreamcast/psx/pcsx-dc.html

https://emulation.gametechwiki.com/index.php/Bleem!

Debian based distro variant, using RedHat bootloader, with X and such. Various names used. Any info on the internet about “Debian” or “RedHat” on DC is this image.

https://web.archive.org/web/20191030122702/http://www.lxdream.org/wiki/index.php?title=Dreamcast_Linux

https://sparrdrem.github.io/homeware/roms/dcroms/dclinux

https://www.angelfire.com/dc2/fer/dclinux.html

operating system for the Sega Dreamcast based on the KallistiOS kernel

Mainly for playing ripped games, but supports programs, video, internet (browser unknown), etc.

http://www.dc-swat.ru/page/dreamshell/

https://github.com/DC-SWAT/DreamShell

https://www.youtube.com/watch?v=XqFFZiR9tyw

https://www.youtube.com/watch?v=2XazHRdyCSg

This device runs an operating system which is known to emulate various devices with EOPs. See the AmigaOS, DOS, MSX, and NEC PC-9801 series pages.

Gentoo has a prebuilt stage3 for SH4 (under experimental/sh/stages) dated Apr 2007

Confusingly listed, but the stage3-sh4-2006 files contain some mentions of Dreamcast.

https://web.archive.org/web/20191030122702/http://www.lxdream.org/wiki/index.php?title=Dreamcast_Linux

https://web.archive.org/web/20080405233743/http://www.gtlib.gatech.edu/pub/gentoo/experimental/sh/stages/

https://web.archive.org/web/20070502223433/http://www.gentoo.org/main/en/mirrors.xml

The most recent kernel versions for DC. Requires some funky downloading thru the net, via broadband adapter(?). LinuxDC is the original iteration, and is now best for documents only.

http://linuxdc.sourceforge.net/

http://www.linux-sh.org/shwiki/Dreamcast/

https://dcemulation.org/index.php?title=LinuxDC

Dreamcast port is far from optimized. Most, if not all games and applications will run very slow

The inferior way for plain DOS on DC. Old, slow, weak compatibility.

https://www.dreamcast.nu/en/ms-dos-emulation-dreamcast/

https://emulationrealm.net/downloads/file/1072-dosboxdc

https://dcemulation.org/phpBB/viewtopic.php?t=73889

The most recent and effective port, it seems. Has various versions. X server, video, etc. supported.

http://wiki.netbsd.org/ports/dreamcast/

https://www.netbsd.org/ports/dreamcast/faq.html

https://www.netbsd.org/ports/dreamcast/howto.html

https://www.youtube.com/watch?v=XeQ11reoOMQ

https://dcemulation.org/index.php?title=NetBSD_DC

https://www.youtube.com/watch?v=m4KC4w7ePMU

Whether these emulators support operating systems for these computers is unknown; it must be looked into further. PCs without meaningful OSes are not included.

https://www.zophar.net/consoles/dreamcast.html

https://dcemulation.org/index.php?title=Emulators

Amstrad CPCs – Dream CPC 1.0 Alpha 3, CPCast

http://www.jm1200.fr/index.php?r=2 https://www.cpcwiki.eu/index.php/Emulators

Apple IIs – Apple II Soul Captor, DCider

ARM Cortex-M23 – uM23 for VMU

http://dmitry.gr/index.php?r=05.Projects&proj=25.%20VMU%20Hacking

Atari 8-bits – Atari800DC

http://www.groessler.org/a800dc/index.html

Atari STs – DcaSTaway

CHIP-8 – Whack-a-Mole, CrabEmu

Commodore 64 – DreamFrodo, DC=64, Panera 64

Commodore Amigas – UAE4ALL

Dragon 32/64 - DragonDC

MSXs – DreamMSX, fMSX DC, MSXCast, uMSX, MadriSX

NEC PC-9801s – Neko Project II

Sinclair ZX Spectrums – DCSpeccyal’K, DreamSpec, fbzxDC, ZX4ALL

http://chui.dcemu.co.uk/zx4all.html

x86 - bhole

Never released, due to corporate licensing. Worked reasonably well, sorta.

http://www.sporktania.com/qnxdc/

https://web.archive.org/web/20090926172517/http://www.qnxzone.com/~jeremy/qnxdc

https://developers.slashdot.org/story/02/09/04/180236/qnx-on-sega-dreamcast

https://www.osnews.com/story/1671/qnx-62-on-sega-dreamcast/

https://www.openqnx.com/newsgroups/viewtopic.php?t=21333

https://dcemulation.org/phpBB/viewtopic.php?f=34&t=39161

Looks interesting and has reasonably advanced function for the time.

https://www.youtube.com/watch?v=VrLca87DMOo

Dreamcast Alternate BIOS (“Real Mode”) with Puyo Puyo Fever

You can get this with save data from Puyo Puyo Fever by inputting some buttons. Esoteric variation

https://www.youtube.com/watch?t=87&v=4uuGo_js6fQ

https://www.youtube.com/watch?v=vDUv5JGWOe8

a work-in-progress IBM-PC 8086 Emulator

Some sort of basic x86 emulator not updated for a while. Runs Windows 3 (and DOS), slowly.

https://www.youtube.com/watch?v=vVRaDlvYY9Y

https://www.youtube.com/watch?v=7Q4Mhvwf5_w

https://www.youtube.com/watch?v=rUvbQKnvpxw

https://www.dreamcast.nu/en/ms-dos-emulation-dreamcast/

bundling simple operating systems within the discs themselves

A basic SDK/layer included on a reasonable amount of DC games. Did nothing for end users. Could in theory be expanded, w/ kernel alterations and driver inclusions. Last link has some porting.

https://segaretro.org/Windows_CE

https://dreamcast-talk.com/forum/viewtopic.php?t=7945

https://dreamcast-talk.com/forum/viewtopic.php?t=10033

https://web.archive.org/web/20170111221115/http://assemblergames.com/l/threads/windows-ce-os-gui-shell-is-possible.64930/

https://github.com/FaucetDC/WincastCE

DreamArena 2.0 was a nearly completed but never released browser update

A new homebrew project to create an even better internet browser for the Dreamcast, which appears to be doing quite well.

https://dreamcast-talk.com/forum/viewtopic.php?f=5&t=13676

Slightly developed port using WinCE.

https://www.reddit.com/r/dreamcast/comments/73qieg/internet_explorer_on_a_dreamcast_because_why_not/

https://www.dreamcast-talk.com/forum/viewtopic.php?f=2&t=10561&start=50

Stock web browsers for the Dreamcast, meant for USA, Japan, and Europe/Australia, respectively. PlanetWeb is the best, apparently, but has bugs in 3.0 (while also having more features?)

https://dcemulation.org/index.php?title=DreamKey

https://web.archive.org/web/20020605140804/http://dc.dricasworld.com/?20011113b

http://www.mediafire.com/file/yxcmyd2mgj3cz4z/PWBROWSER2.zip (custom mod)

the WebTV browser was an improvement over Sega's bundled Dream Passport software

Now defunct Japanese service allowing access to Microsoft’s WebTV.

https://segaretro.org/WebTV_for_Dreamcast

Custom alternative to PlanetWeb developed more recently.

http://dreamcastlive.net/files/XDP%20Limited%20Edition%20R-4.zip