PumpsOS

## What is it?

PumpsOS is my journey into operating system development — building a kernel from absolute scratch. No GRUB, no Linux, no training wheels. Just assembly, C, and a lot of documentation reading and help from OSDevers.

## Why I built it

Because understanding operating systems from textbooks isn't the same as building one. I took a course in Operating Systems and I wanted to know exactly what happens from the moment a computer boots to the first pixel appearing on screen. Something that only hands-on experience could deliver. Although without the knowledge of the module, I would not of had this idea in the first place. Thank you Professor Andrew Scott

## Features implemented

Being an on-going project, there are many features still to come! But some currently include:

• Custom bootloader in Assembly
• VGA text mode driver
• Terminal with scrolling
• PS/2 keyboard driver

## Challenges

• Protected mode transition - one wrong bit and everything crashes
• Debugging without a debugger - need a real sharp eye for this one
• Scan code tables for keyboard input - hundreds of lines
• Memory management without malloc

## What I learned

• x86 architecture and real/protected mode
• How hardware interrupts work
• VGA memory-mapped I/O
• The boot process in detail
• Cross-compilation and bare-metal development