GoKawiilFreeBSD Device Drivers
From First Steps to Kernel Mastery
by Edson Brandi · Version 2.0 (April 2026)
About This Book
FreeBSD Device Drivers: From First Steps to Kernel Mastery is a free, open-source book that takes you from "I've never written kernel code" to "I can write, debug, and submit production-quality FreeBSD drivers." It is a guided course rather than a reference, structured around 38 chapters, 6 appendices, and dozens of hands-on labs that compile and load on a real FreeBSD 14.x system.
The book is aimed at readers who are willing to learn rather than are already qualified. It begins with UNIX fundamentals and the C language, walks step by step through every concept the kernel will demand of you, and only then opens the door to driver development. By the time you reach DMA, interrupts, and PCI work, the vocabulary feels earned, not imposed.
"Kernel programming is still programming, only with more explicit rules, greater responsibility, and a bit more power. Once you understand that, the fear gives way to excitement." (from Chapter 1)
Why This Book?
There are excellent FreeBSD kernel references already, including man 9 , the Architecture Handbook, and the Newbus papers. What has been missing is a single text that:
Starts from zero. UNIX, C, and the FreeBSD environment are taught before any kernel code is written.
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