30 Days to Build an Operating System

About the Book

“30 Days to Build an Operating System” is a one-of-a-kind hands-on technical book. Over a 30-day program, author Hidemi Kawai walks readers step by step through building a miniature operating system — complete with a graphical interface, multitasking, and more — starting from the lowest-level assembly language. The content advances gradually with detailed code, making it a great fit for readers who want to truly understand how operating systems work.

Core Concepts

According to your journal, you read this book in April 2020. Its core hands-on topics include:

1. Boot and startup: understanding how a computer starts from the BIOS and loads the boot sector of the operating system.
2. Memory management: learning to manage and allocate memory to give programs room to run.
3. Interrupt handling: mastering how to respond to hardware interrupts (such as keyboard and mouse input) to enable human-computer interaction.
4. Multitasking: implementing a simple task-switching mechanism so that multiple programs can run “simultaneously.”
5. Graphical interface: learning to draw windows, buttons, and other elements on screen to build a basic GUI.

Key Takeaways

Following “Code,” this book took your exploration of the lowest levels of computing a step further. In 2020, as you went deeper into back-end development, understanding the operating system became especially important. Through hands-on practice, the book gave you a more intuitive and deeper grasp of core concepts such as processes, threads, memory, and I/O. That accumulation of low-level knowledge was a solid stepping stone from application developer toward system architect, laying firm groundwork for handling high-concurrency, high-performance back-end services later on.