The latest articles on DEV Community by Gyimah-Benjamin (@janosdev). https://dev.to/janosdev https://media2.dev.to/dynamic/image/width=90,height=90,fit=cover,gravity=auto,format=auto/https:%2F%2Fdev-to-uploads.s3.amazonaws.com%2Fuploads%2Fuser%2Fprofile_image%2F3948882%2Fe668b1fe-63ea-4c00-819b-3c716543a53b.jpg https://dev.to/janosdev en Gyimah-Benjamin Sun, 24 May 2026 10:33:08 +0000 https://dev.to/janosdev/i-built-a-32-bit-os-from-scratch-and-named-it-after-my-mom-5gam https://dev.to/janosdev/i-built-a-32-bit-os-from-scratch-and-named-it-after-my-mom-5gam <h2> The Beginning </h2> <p>A few months ago I didn't know what a bootloader was.<br> Today I have a working 32-bit operating system called <br> JanOS — named after my mom who supported me through <br> the entire journey.</p> <h2> What is JanOS? </h2> <p>JanOS is a 32-bit x86 operating system built completely <br> from scratch in C and x86 Assembly. No frameworks. <br> No shortcuts. Every line written and understood.</p> <h2> What it can do </h2> <ul> <li>Custom bootloader that loads the kernel via LBA</li> <li>32-bit protected mode with GDT</li> <li>FAT12 file system (read, write, delete files)</li> <li>Persistent storage via custom ATA driver</li> <li>Shell with 10+ commands</li> <li>Memory management with paging</li> <li>Hardware cursor</li> <li>Keyboard with shift support</li> <li>History navigation with arrow keys</li> <li>Screen scrolling</li> </ul> <h2> The hardest part </h2> <p>Making files persist across reboots was the biggest <br> challenge. I had to write a custom ATA driver that <br> talks directly to the disk controller hardware through <br> ports. No BIOS, no shortcuts — just raw hardware <br> communication.</p> <h2> What I learned </h2> <ul> <li>How the CPU actually boots</li> <li>How memory is really managed</li> <li>How files are actually stored on disk</li> <li>How keyboard input really works</li> </ul> <h2> Video </h2> <p> <iframe src="https://www.youtube.com/embed/zJf154-crlg"> </iframe> </p> <h2> Screenshot </h2> <p><a href="https://media2.dev.to/dynamic/image/width=800%2Cheight=%2Cfit=scale-down%2Cgravity=auto%2Cformat=auto/https%3A%2F%2Fdev-to-uploads.s3.amazonaws.com%2Fuploads%2Farticles%2F29ikqceyd9kvpkre5bbc.png" class="article-body-image-wrapper"><img src="https://media2.dev.to/dynamic/image/width=800%2Cheight=%2Cfit=scale-down%2Cgravity=auto%2Cformat=auto/https%3A%2F%2Fdev-to-uploads.s3.amazonaws.com%2Fuploads%2Farticles%2F29ikqceyd9kvpkre5bbc.png" alt=" " width="713" height="460"></a></p> <p><a href="https://media2.dev.to/dynamic/image/width=800%2Cheight=%2Cfit=scale-down%2Cgravity=auto%2Cformat=auto/https%3A%2F%2Fdev-to-uploads.s3.amazonaws.com%2Fuploads%2Farticles%2Flmpdvenqx3caot19bo8v.png" class="article-body-image-wrapper"><img src="https://media2.dev.to/dynamic/image/width=800%2Cheight=%2Cfit=scale-down%2Cgravity=auto%2Cformat=auto/https%3A%2F%2Fdev-to-uploads.s3.amazonaws.com%2Fuploads%2Farticles%2Flmpdvenqx3caot19bo8v.png" alt=" " width="721" height="457"></a></p> <h2> What's next </h2> <ul> <li>IDT (interrupt handling)</li> <li>Multitasking</li> <li>GUI</li> </ul> <h2> Try it yourself </h2> <p>GitHub: <a href="https://github.com/Gyimah-Benjamin/JanOS" rel="noopener noreferrer">https://github.com/Gyimah-Benjamin/JanOS</a></p> <p>Still building. This is just the beginning 🚀</p> programming showdev sideprojects systems