June 2026 · Operating Systems · x86 Assembly
As part of my exploration into operating system development, I set out to implement a simple credential system directly within a custom x86 operating system. The objective was to introduce basic user authentication during the boot process and gain a deeper understanding of how persistent data can be managed in a low-level environment.
Unlike application development, operating system development provides no access to libraries, databases, or operating system services. Every component must be designed and implemented from scratch, making even a basic login system an interesting engineering challenge.
The system reserves a dedicated disk sector for credential storage. A flag byte is used to indicate whether valid account information exists.
During startup, the bootloader reads this sector and determines which workflow should be displayed. If no account exists, the system enters account creation mode. If an account has already been created, the system presents the login screen.
This lightweight approach allows the operating system to maintain state across reboots while remaining simple and efficient.
One of the first challenges I encountered was preserving account data during development.
Rebuilding the operating system image frequently overwrote the credential sector, causing stored account information to be lost. To solve this problem, I developed a small build workflow that automatically preserves credential data between builds.
The workflow extracts the credential sector before rebuilding the operating system image and restores it afterwards. This allows account information to survive development iterations and significantly improves the testing experience.
Most importantly, this project demonstrated how features that appear straightforward at the application level become significantly more complex when implemented close to the hardware.
This credential system represents one of the foundational components of a larger operating system project.
Future development will focus on kernel improvements, enhanced user interaction, storage abstractions, and additional system services.
Operating system development has been one of the most challenging and rewarding areas of programming I have explored so far, and this project was an important step in that journey.