Hi @tleilax. It makes me happy to see others interested in DOS development too! I am a DOS dev newbie, but aspire to create a real game one day.
Abrash’s Big Black Book is fantastic if you want to get into the nuts-and-bolts of the VGA machinery, but it reads very much like a technical manual, with a focus on assembly language. I found it a hard entry point into DOS programming. It’s on my reading list for the future, but until then I have to accumulate more experience.
I have a copy of Jonathan S. Harbour’s “Game Programming All in One 2nd Edition”. The writing is easy to read, and follows a tutorial style of building a demo game, spanning the chapters. I should note that the book is tied to the Allegro DOS game library. Available Amazon.
David Brackeen’s C VGA tutorial really helped get me started. It covers the basics in C – Entering video mode, drawing primitives and bitmaps, palette manipulation and double buffering.
Then if you want to get into a little more advanced techniques, I can recommend Lode Vandevenne graphics tutorials – flood fills, plasmas, fires, raycasting, image filtering and procedural texture generation.
I can also recommend Root42’s Let’s Code video tutorials. I find these a pleasure to watch.
http://www.brackeen.com/vga/index.html
https://lodev.org/cgtutor/
https://www.youtube.com/playlist?list=PLGJnX2KGgaw2L7Uv5NThlL48G9y4rJx1X