# **Essence** — An Operating System

![Discord](https://img.shields.io/discord/703653809943085186?color=blue) ![Automated build status](https://img.shields.io/github/workflow/status/nakst/build-essence/nightly)

![Screenshot showing the file manager, text editor, and bitmap image editor.](https://nakst.gitlab.io/essence.jpg)

Video demonstration as of October 2021, running on real hardware: (YouTube) 

[![Video demonstration as of October 2021.](http://img.youtube.com/vi/aGxt-tQ5BtM/0.jpg)](http://www.youtube.com/watch?v=aGxt-tQ5BtM "Essence — October ’21 Progress")

## Links

For discussion, join our Discord server: https://discord.gg/skeP9ZGDK8. 

Alternatively, visit the forums (not very active): https://essence.handmade.network/forums.

## Supporters

To support development, you can donate to my Patreon: https://www.patreon.com/nakst.

Essence was a recipient of the prestigious 2021 Icculus Microgrant. You can view more details here: https://icculus.org/microgrant/.

## Testing

You can download and test the latest nightly build from https://github.com/nakst/build-essence/releases. Download and extract `Essence.tar.xz`. If you are using VirtualBox, import `Essence.ova`. If you are using Qemu, run 

    qemu-kvm -drive file=drive,format=raw -m 2048 -smp 2 || qemu-system-x86_64 -enable-kvm -drive file=drive,format=raw -m 2048 -smp 2

These builds are configured to run on emulators only, to make testing easier. Builds for real hardware are coming soon :)

## Building

See `help/Building.md` for a description of how to build and test the system.

## Features

Kernel
* Filesystem independent cache manager.
* Memory manager with shared memory, memory-mapped files and multithreaded paging zeroing and working set balancing.
* Networking stack for TCP/IP.
* Scheduler with multiple priority levels and priority inversion.
* On-demand module loading.
* Virtual filesystem.
* Window manager.
* Audio mixer. (being rewritten)
* Optional POSIX subsystem, capable of running GCC and some Busybox tools.

Applications
* File Manager
* Text Editor
* IRC Client
* System Monitor

Ports
* Bochs
* GCC and Binutils
* FFmpeg
* Mesa (for software-rendered OpenGL)
* Musl

Drivers
* Power management: ACPI with ACPICA.
* Secondary storage: IDE, AHCI and NVMe.
* Graphics: BGA and SVGA.
* Read-write filesystems: EssenceFS.
* Read-only filesystems: Ext2, FAT, NTFS, ISO9660.
* Audio: HD Audio.
* NICs: 8254x.
* USB: XHCI, bulk storage devices, human interface devices.

Desktop
* Custom user interface library.
* Software vector renderer with complex animation support.
* Tabbed windows.
* Multi-lingual text rendering and layout with FreeType and Harfbuzz.