HobbyOS is a lightweight, educational UEFI Operating System (Pre-OS) developed to explore the fundamentals of low-level system programming, file system management, and direct hardware interaction without the aid of a standard operating system kernel (like Linux or Windows).
Running directly on Bare Metal x64 architecture, HobbyOS interfaces directly with the UEFI firmware. It features a custom shell, a functional text editor, a complete disk management suite (partitioning, formatting, installation), and a visual interface.
Note: This project is an educational exploration (a "Hobby OS") designed to demonstrate how UEFI applications work under the hood. It is not intended to replace daily driver operating systems, but rather to serve as a learning platform for system architecture.
To build and run HobbyOS, you will need a Linux environment (Ubuntu/Debian recommended) with the following tools installed:
- GCC: The GNU Compiler Collection.
- GNU-EFI: The library used to interface with UEFI services.
- MTools: Utilities to access MS-DOS disks (needed to generate the
.imgfile). - QEMU: To emulate the OS without needing physical hardware.
If you want to test HobbyOS on Physical Hardware you can do it without QEMU.
sudo apt-get update
sudo apt-get install build-essential gnu-efi mtools qemu-system-x86- Clone the Repository
git clone [https://github.com/yourusername/hobby-os.git](https://github.com/yourusername/hobby-os.git)
cd hobby-os- Clean and Build
Use the provided makefile to compile the source code and generate the disk image.
# Clean previous builds
make clean
# Compile the project and create hobbyos.img
make all- Run in QEMU
To test the OS immediately in an emulator:
make runHobbyOS is compatible with modern x64 PCs that support UEFI Boot.
-
Format a USB Pen Drive to FAT32.
-
Inside the
hobby-osfolder (after runningmake), locate the generatedmain.efifile. -
Create the following folder structure on your USB drive:
/EFI/BOOT/. -
Rename
main.efitoBOOTX64.EFIand copy it into that folder. -
Path should be:
USB_ROOT/EFI/BOOT/BOOTX64.EFI -
Copy
logo.bmpto the same folder if you want the splash screen. -
Reboot your PC, enter the BIOS/Boot Menu, and select the USB drive (UEFI mode).
HobbyOS features a custom shell with history support. Below is the list of available commands:
System & Navigation
| Command | Arguments | Description |
|---|---|---|
| ls / dir | - |
Lists files and directories in the current path. |
| cd | <folder> or .. |
Changes directory. Use .. to go back. |
| pwd | - |
Prints the current working directory. |
| vol | [id] |
Lists available volumes (FS0, FS1) or mounts one if an ID is provided. |
| ver | - |
Displays system version and architecture info. |
| date | - |
Shows current RTC date and time. |
| mem | - |
Displays total and free RAM (UEFI Memory Map). |
| shutdown | - |
Safely powers off the machine. |
| restart | - |
Reboots the system. |
| clear | - |
Clears the terminal screen. |
File Operations
| Command | Arguments | Description |
|---|---|---|
| edit | <filename> |
Opens the built-in Visual Text Editor. Ctrl + C to Save, Ctrl + X to Exit. |
| cat | <filename> |
Displays the contents of a text file. |
| mkdir | <name> |
Creates a new directory. |
| touch | <filename> |
Creates a new empty file. |
| rm | <name> [-r] |
Deletes a file. Use the -r flag for recursive directory deletion. |
| cp | <src> <dst> |
Copies a file from source to destination. |
| hexdump | <filename> |
View the binary content of a file in hexadecimal format. |
Disk & Installation Tools
⚠️ Warning: These commands can modify or wipe disks. Use with caution.
| Command | Arguments | Description |
|---|---|---|
| disks | - |
"X-Ray" view of connected block devices, showing size, type, and partition tables. |
| gptinit | <disk_idx> |
Wipes the disk and initializes a fresh GPT header with a Protective MBR. |
| part | <disk> <LBA> <MB> |
Creates a new partition on the specified disk. |
| format | <disk> <part> [fast/full] |
Formats a partition to FAT32. Default mode is fast. |
| install | <disk> <part> |
Installs the HobbyOS system files onto the target partition. |
HobbyOS includes a complete installer suite capable of partitioning and formatting drives.
⚠️ Warning: These commands modify your hard drive. Data loss is permanent. Use with caution.
Step 1: Identify Drives
Run disks to see the list of connected drives. Identify the target disk index (e.g., 1).
Step 2: Initialize GPT
If the disk is empty or raw, create the partition table:
gptinit 1Step 3: Create a Partition
Create a partition starting at LBA 2048 (standard alignment) with a size of 500MB:
part 1 2048 500Step 4: Format as FAT32
Format disk 1, partition 0 (the first partition) using the fast method:
format 1 0 fastNote: You must reboot your computer or re-plug the drive if the UEFI firmware doesn't refresh the file system handle immediately.
Step 5: Install System
Copies BOOTX64.EFI and necessary system files to the new drive:
install 1 0Once finished, you can remove the USB and boot from the newly installed drive.
Contributions are welcome! If you want to add features like a new file system driver, improve the text editor, or add a game (like the DOOM folder structure suggests):
-
Fork the project.
-
Create your feature branch (
git checkout -b feature/AmazingFeature). -
Commit your changes (
git commit -m 'Add some AmazingFeature'). -
Push to the branch (
git push origin feature/AmazingFeature). -
Open a Pull Request.
Distributed under the MIT License. See LICENSE for more information.
