Snowdrop OS - my operating system from scratch, in assembly language
http://sebastianmihai.com/snowdrop/
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?
The Snowdrop OS and the apps are distributed as both a floppy disk (1.44Mb) image, as well as a CD-ROM image. The images contain the following, all programmed from scratch:
- a boot loader which loads the kernel into memory
- a kernel which sets up interrupt vectors to be used by user apps, and then loads the startup app
- user apps, including a shell (command line interface), utilities, test apps, and aSMtris, my Tetris clone
Snowdrop OS can also be installed to a hard disk - prompting the user to do so during boot - if it detects one.
I hope that Snowdrop can serve other programmers who are looking to get a basic understanding of operating system functions. Like my other projects, the source code is fully available, without any restrictions on its usage and modification.
originally posted at https://stacker.news/items/862821