The latest articles on DEV Community by FelineFantasy (@felinefantasy). https://dev.to/felinefantasy https://media2.dev.to/dynamic/image/width=90,height=90,fit=cover,gravity=auto,format=auto/https:%2F%2Fdev-to-uploads.s3.us-east-2.amazonaws.com%2Fuploads%2Fuser%2Fprofile_image%2F4090989%2Fbb9a63b5-1734-4e8d-a92d-a89a4d70c82b.jpg https://dev.to/felinefantasy en FelineFantasy Sun, 23 Aug 2026 16:07:05 +0000 https://dev.to/felinefantasy/im-13-and-i-built-a-16-bit-os-in-assembly-2l50 https://dev.to/felinefantasy/im-13-and-i-built-a-16-bit-os-in-assembly-2l50 <p>I'm 13 and I wrote a 16-bit OS in assembly. 🐱</p> <p>It's called <strong>CatOS</strong> — real-mode bootloader, BIOS interrupts, and a cat on error.</p> <ul> <li>Bootloader → loads kernel from floppy</li> <li>Kernel → prints text via <code>int 0x10</code> </li> <li>Panic screen → cat says "disk read error"</li> </ul> <p>example cat says "disk read error"<br> </p> <div class="highlight js-code-highlight"> <pre class="highlight plaintext"><code> /\_/\ ( o.o ) &gt; Disk read error! &gt; ^ &lt; </code></pre> </div> <h2> What's next? Not sure. </h2> <p>I already managed to add a basic keyboard input! Here is how the OS looks right now:</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.us-east-2.amazonaws.com%2Fuploads%2Farticles%2Fgpwamr9rr876jvzmi9u2.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.us-east-2.amazonaws.com%2Fuploads%2Farticles%2Fgpwamr9rr876jvzmi9u2.png" alt="CatOS Interactive Screen" width="800" height="450"></a><br> <em>You can type here btw!</em></p> <p>Here are my thoughts on what to build next:</p> <ul> <li> <strong>FAT16?</strong> (To actually load files)</li> <li> <strong>Better Keyboard Handler?</strong> (To support shift, backspace, and enter)</li> <li> <strong>Protected mode?</strong> (Switching to 32-bit sounds fun but scary)</li> <li> <strong>Mouse support?</strong> (Reading mouse packets via <code>int 0x33</code> and drawing a custom cursor!)</li> </ul> <p>Drop your ideas in the comments 👇<br> GitHub: <a href="https://github.com/FelineFantasy/CatOS" rel="noopener noreferrer">FelineFantasy/CatOS</a></p> assembly osdev showdev beginners