Gramado

Gramado is a 64bit kernel.

Overview

Gramado OS is a project that includes the bootloader, the core kernel, and the init process.

Important

Documentation for this distribution is still under development. Folder names are subject to change.

The folders

distros/ - Complete distributions are built here.
docs/    - Documentation.
kernel/  - The kernel, including the bootloader, kernel modules, and 
           applications (see kernel/core/apps/).
tools/   - SDK tools.

Special folder.

kernel/core/deps/:
- Bootloader and kernel modules.
- POSIX commands.
- Display server and client-side GUI applications.

Where is the boot loader?

kernel/core/deps/kcore/boot/

Where is the kernel?

kernel/

Where are the ring 0 kernel modules?

kernel/core/deps/kcore/modules/

Where is the Init Process?

kernel/core/deps/ucore/init/

Where is the ring 3 device drivers?

kernel/core/deps/ucore/drivers/

Where is the ring 3 servers?

kernel/core/deps/ucore/servers/

Where is the display server?

kernel/core/gdeps/preshell/ds/ds00/

Where are the POSIX-like command programs?

kernel/core/gdeps/shell/shell00/

Where are the client-side GUI applications?

kernel/core/gdeps/shell/shell01/

Important

Gramado OS kernel is in a pre-alpha state and is only suitable for developers.

What is Gramado OS Kernel?

Gramado OS Kernel includes the bootloader, the core kernel, and the init process.

Kernel initialization

The kernel initialization in I_kmain():

// ==================================
// Levels:
// + [1]   earlyinit()
// + [2:0] mmInitialize(0)
// + [2:1] mmInitialize(1)
// + [3:0] keInitialize(0)
// + [3:1] keInitialize(1)
// + [3:2] keInitialize(2)
// + [4]   archinit()
// + [5]   deviceinit()
// + [6]   lateinit()
// ==================================

What is Gramado Operating System?

GramadoOS is a 64-bit graphical operating system, featuring a bootloader, kernel, and a desktop environment. This is the first distribution created using the Gramado OS kernel.

This image shows the first process that runs after the kernel initialization.

You can install a desktop environment on top of the kernel. The default desktop environment is located in the gdeps/ folder.

What is the category it belongs to?

Gramado OS is a hobby operating system. It is not a commercial system; it is small and offers only a limited set of features.

Kernel features.

Hardware Support
CPU: Intel and AMD, 64-bit only
Memory: Paging, 2MB chunks using 4KB pages
Block device: IDE (Primary master only)
Character devices: PS/2 keyboard, PS/2 mouse (works best in QEMU), Serial port (COM, used for debugging)
Network: Intel e1000 NIC (works in Oracle VirtualBox)

Software
Processes and threads
Round-robin scheduler (threads only)
Syscalls via software interrupts (traps)
IPC: sockets and system messages (queue in thread structure)
4 ring 0 kernel virtual consoles (fullscreen raw mode)
General-use TTYs and PTYs for ring 3 virtual terminals
FAT16 file system for boot partition (no dedicated system partition yet)
POSIX libc: ring 0 implementation for ring 3 libraries
Basic networking: sockets, small ring 0 protocol stack (Ethernet, ARP, IP, UDP, TCP, DHCP)
Display: Bootloader display device (VESA)
Minimal user structure
Loadable ring 0 module (static address)

Userland features.

Display server
Unix-like commands in the virtual console
Some clients connect to the display server via Unix sockets
Ring 3 processes can access I/O ports via syscall (for ring 3 drivers only)

userland system programs.

• The network server. (Work in progress)

userland commands.

See deps/ucore/cmds/.

DE - Desktop Environment

This is a screenshot of the desktop environment running on top of the kernel. You can find code in the gdeps/ folder.

Gramado API

You can find the API to create client-side GUI application in gdeps/.

Demos

This is a screenshot of 3D demo running on top of the kernel. You can find code in the zde/aurora/ folder.

The source code.

  You can find the source code on Github on the internet, 
  where you can clone the repository, contribute to the project or
  download the code. The address is https://github.com/frednora/gramado.

Notes on Building an OS

Building an operating system is a great way to learn how systems work and 
to understand the full software stack required to run applications.
However, if your goal is to make money, high demand is typically found in 
application development (web front-end and back-end).

Who are the developers?

• Main Developer: Fred Nora, a Brazilian developer (creator and maintainer)
• Contributions: All are welcome!

Important

Build instruction

Building and Running on VM

$ make
$ ./run

ps: Do NOT use the fancy '-j' thingy for now.

Cleaning Up for a Fresh Compilation

$ make clean-all

What are the host machine to build the project?

• Gramado OS has been compiled and tested on Ubuntu LTS releases, including WSL2 on Windows and various Ubuntu versions.
• A typical build environment:

    Host machine: Windows 10, wsl2 with Ubuntu.
    Linux kernel: 5.15.146.1-microsoft-standard-WSL2
    gcc (Ubuntu) 11.4.0 
    GNU ld (GNU Binutils for Ubuntu) 2.38
    NASM version 2.15.05

    Host machine: Ubuntu 20.04.5 LTS
    Linux 5.4.0-146-generic x86_64
    gcc (Ubuntu) 9.4.0 
    GNU ld (GNU Binutils for Ubuntu) 2.34
    NASM version 2.14.02

    Host machine: Ubuntu 22.04.2 LTS
    Linux 5.15.0-78-generic x86_64
    gcc (Ubuntu) 11.4.0 
    GNU ld (GNU Binutils for Ubuntu) 2.38
    NASM version 2.15.05

    Host machine: Ubuntu 22.04.2 LTS
    Linux 5.15.0-83-generic x86_64
    gcc (Ubuntu) 11.4.0 
    GNU ld (GNU Binutils for Ubuntu) 2.38
    NASM version 2.15.05

    Host machine: Ubuntu 22.04.2 LTS
    Linux 5.15.0-84-generic x86_64
    gcc (Ubuntu) 11.4.0 
    GNU ld (GNU Binutils for Ubuntu) 2.38
    NASM version 2.15.05

    Host machine: Ubuntu 22.04.2 LTS
    Linux 5.15.0-87-generic x86_64
    gcc (Ubuntu) 11.4.0 
    GNU ld (GNU Binutils for Ubuntu) 2.38
    NASM version 2.15.05

    Host machine: Ubuntu 22.04.2 LTS
    Linux 5.15.0-89-generic x86_64
    gcc (Ubuntu) 11.4.0 
    GNU ld (GNU Binutils for Ubuntu) 2.38
    NASM version 2.15.05

Testing

• Virtual Machines: Tested on QEMU, QEMU with KVM, and VirtualBox.
• Physical Machines: Older versions tested on real hardware (e.g., Intel Core 2 Duo, VIA chipset).

Can I test the system on a virtual machine?

Yes, you can test the system on a virtual machine. The system has been tested by Fred Nora on qemu, qemu with kvm and virtualbox. Now, Fred Nora is testing the system only on qemu and virtualbox.

Can I test the system on a real machine?

Yes, we can test the system in the real machines. This way we can improve the system. The older versions of the system were tested for a long period of time on a real machine. That machine was a Gigabyte machine with an Intel Core 2 Duo processor and a VIA chipset.

Feedback

Feedback from users and developers is appreciated! Feel free to comment on GitHub or contact Fred Nora directly.

Author

• Fred Nora - Fred Nora's X account
• Fred Nora - Fred Nora's Facebook account

Contributors

• Fred Nora - Fred Nora's X account
• Fred Nora 2 - Fred Nora's Facebook account

How to Build?

See the Gramado OS build instructions

Warning

You're reaching the boring area of this document!

Documentation

Documentation and design notes are in the docs/ folder.

See the docs.

The project is looking for some people to create a better documentation, for free, as a contribuition to the open source community. To create this new documentation we can use the documentation in docs/ and the design notes found all over the project.

License

Gramado OS is Free and Open Source. The source code uses the MIT License.

Quotes:

    "Orthodox church"