GitHub - Microsoft/MS-DOS

rubbermallet.org Where QuickBASIC gets much more powerful. IRC server and client. Webserver. POP3/SMTP email client.

GitHub - volkertb/temu-vsb TEMU (“Tandy Emulator”) and VSB (“Virtual Sound Blaster”), two nifty MS-DOS TSR utilities originally developed by Andrew Zabolotny
GitHub - volkertb/JUDAS Apocalyptic Softwaremixing Soundsystem

Brutman.com and Brutmanlabs.org.

Computer History Museum - Microsoft MS-DOS early source code

DOSSound AC'97 Sound driver and wave file player for DOS.
DOSUSB is a USB controller driver for DOS. It supports USB 3.0, USB 2.0 and 1.1 with xHCI, EHCI, UHCI and OHCI controllers. DOSUSB enables DOS drivers and applications to communicate with any USB device. DOS device drivers for USB flash drives, USB printers and many samples are included. (commercial software)
COMPUTERCRAFT - CD ROM Drivers
NANSI.SYS is a console device driver for MS-DOS computers. It executes the same ANSI cursor control sequences as does the standard console driver ANSI.SYS, but significantly faster. It also offers several extra features, while still being simple, small, and cheap.

YouTube - 486 100MHz MS-DOS PC Build! by Tech Tangents.

YouTube - Ultimate Roland compatible MPU-401 MIDI Interface Card with Intelligent Mode by PhilsComputerLab.

Keropi and Marmes retro computing projects site

Serdashop MIDI SYNTHESIZER MODULES, BREAKOUT BOARDS AND INTERFACES.