FRANK OS 1.0 Launches With a Retro Windows 95-Like Desktop

Blending retro inspiration with embedded development, a new open-source project named FRANK OS has introduced an interesting idea: running a full graphical desktop operating system on a microcontroller. The project has now reached an important milestone with the release of version 1.0.

A Different Kind of Desktop OS

Unlike most desktop systems, FRANK OS does not rely on the Linux kernel. Instead, it is built on top of FreeRTOS, a real-time operating system widely used in embedded and IoT devices. On this lightweight RTOS base, the developers created their own graphical interface, system libraries, and small applications.

Designed for Microcontroller Hardware

The system is designed specifically for hardware powered by the RP2350 microcontroller, which provides roughly 520 KB of SRAM and two CPU cores. One core manages the FreeRTOS scheduler, the desktop interface, and running applications, while the second core focuses on generating real-time video output through a DVI connection.

Retro Desktop Experience

The graphical interface pays tribute to the classic look of Windows 95. 🖥️ The desktop features familiar elements such as overlapping windows, a taskbar, and a start-menu-style launcher. Despite the limited hardware resources, the environment includes common desktop tools like a file manager, terminal, and several basic utilities.

The built-in window manager supports typical desktop actions, including:

• Title bars with minimize, maximize, and close buttons
• Dragging windows to move them
• Resizing from edges or corners
• Switching between applications using an Alt+Tab-style shortcut

A taskbar at the bottom shows active programs and offers quick access to the Start menu. It also includes a small system tray displaying items like the clock and volume control.

Built-in Applications

FRANK OS 1.0 comes with nine lightweight applications, demonstrating what can be achieved on such limited hardware. These include:

• A terminal featuring the interactive PShell
• A Vi-based text editor
• A C compiler
• Simple games like Minesweeper and Solitaire
• An MP3 player
• A ZX Spectrum emulator

The system also includes a windowed version of MMBasic, a BASIC interpreter capable of handling file operations, graphics commands, and audio output.

Expandable with External Apps

Applications are compiled as ARM ELF binaries and loaded from an SD card. This design allows users to add new programs without rebuilding the operating system firmware, making experimentation easier for developers and hobbyists.

A Fun Project for Experimenters

FRANK OS is primarily an experimental and educational project, aimed at enthusiasts interested in embedded systems and retro-style computing. While it’s not intended to replace mainstream desktop operating systems, it’s an exciting demonstration of what can be achieved with minimal hardware resources—and it certainly brings a dose of nostalgia.

Developers interested in trying it out can explore the project on its GitHub repository. The system is distributed as open source under the MIT license.