Snowdrop OS: a homebrew operating system from scratch, in x86 assembly language

Snowdrop OS was born of my childhood curiosity around what happens when a PC is turned on, the mysteries of bootable disks, and the hidden aspects of operating systems. It is a 16-bit real mode operating system for the IBM PC architecture. I designed and developed this homebrew OS from scratch, using only x86 assembly language.

I have created and included a number of utilities, including a file manager, text editor, graphical applications, BASIC interpreter, x86 assembler and debugger. I also ported one of my DOS games to it. After all, what kind of an operating system doesn’t have games?

↫ Snowdrop OS’ website

It seems like every talented programmer will, at some point, think to themselves: I should write my own operating system. Most of these efforts strand pretty quickly – and that’s fine! – but Sebastian Mihai’s effort did not, and it has grown into a very capable operating system, especially given the constraints stemming from the chosen architecture – 16bit realmode x86 – and programming language – x86 assembly. Snowdrop OS is an incredibly impressive labour of love, and comes with a unique extra I haven’t seen before: a daily development log covering over 600 days of development.

No, this won’t take over the world, but I love that is exists. More of this, please.

4 Comments

  1. 2025-01-22 8:34 pm
    • 2025-01-23 1:16 am
  2. 2025-01-22 9:16 pm
  3. 2025-01-23 3:34 am

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