TacOS Is a Functional UNIX-Like Operating System Written From Scratch — and Yes, It Plays Doom
"Please note that TacOS is a hobby toy OS," developer Jake Steinburger says — echoing the origins of Linux.
Developer Jake Steinburger, also known as "UnmappedStack," has released a UNIX-like operating system written from scratch — yet capable of playing id Software's classic first-person shooter Doom: TacOS.
"TacOS [is] my from-scratch OS with it's own kernel written in C and assembly," Steinburger explains of the project. "TacOS is a UNIX-like kernel which is able to run Doom, among various other smaller userspace programs. It has things like a VFS [Virtual Filesystem], scheduler, TempFS [Temporary Filesystem], devices, context switching, virtual memory management, physical page frame allocation, and a port of Doom. It runs both on real hardware (tested on my laptop) and in the Qemu emulator."
In use, TacOS will be familiar to anyone who has experience of UNIX, Linux, or other POSIX-style operating systems. It boots into a textual console that provides the usual commands for interacting with the filesystem, which is laid out in the traditional UNIX style. As well as these basic commands, there's also a port of Doom Generic — an popular variant of the id Software's 1993 first-person shooter Doom, based on the company's later open-source release.
TacOS builds atop PotatOS, Steinburger's earlier 64-bit kernel project that in turn was a successor to SpecOS. "I ended my previous project, SpecOS, due to the project being quite broken and having code left from when I knew literally nothing about kernel development. PotatOS is a rework now that I understand more," Steinburger wrote at the time, "and while it's still not perfect, I can confidently say that it's already a lot better."
"Please note that TacOS is a hobby toy OS and is not complete enough for real usage," Steinburger says of the currently-available release — echoing, knowingly or otherwise, Linus Torvalds' 1991 announcement of his Linux project, in which he described his work as "just a hobby [which] won't be big and professional like GNU." Unlike TacOS, Linux could not play Doom at the time of its announcement — primarily because id Software wouldn't release the game until two years later.
TacOS is available on GitHub under the Mozilla Public License Version 2, complete with instructions on compiling the operating system and running it in the Qemu emulator.