operating system

45 Articles

A console is shown displaying a system’s startup information, followed by “Booting from Hard Disk …”, “Hello World!” in a green font, and “The keyboard is working!”

A Forth OS In 46 Bytes

May 27, 2025 by 12 Comments

It’s not often that we can include an operating system in a Hackaday article, but here’s the full 46-byte source of [Philippe Brochard]’s 10biForthOS in 8086 opcodes:

50b8 8e00 31d8 e8ff 0017 003c 0575 00ea
5000 3c00 7401 eb02 e8ee 0005 0588 eb47
b8e6 0200 d231 14cd e480 7580 c3f4

Admittedly, this is quite a minimal operating system. It’s written for the Intel 8086, and consists of a Forth implementation with only two instructions: compile (1) and execute (0). It can receive commands over a serial connection or from a keyboard. This allows a host computer to load more complex software onto it, one byte at a time. In particular, [Philippe] provides instructions for loading more advanced compilers, such as subleq-eForth for a more complete Forth implementation, or SectorC for C programming. He’s also written a 217-byte port of the OS to Linux Intel x64.

[Philippe] doesn’t take a strong stance on whether this should technically qualify as a Forth implementation, given that the base implementation lacks stacks, dictionaries, and the ability to define words. However, it does have an outer and inner interpreter, the ability to compile and execute code, and most importantly, “the simplicity and hacky feeling of Forth.”

[Philippe] writes that this masterpiece of minimalism continues the tradition of the minimal Forth implementations we’ve covered before. We’ve even seen Forth run on an Arduino.

A RISC-V Operating System Instruction Manual

May 26, 2025 by 1 Comment

To some, an operating system is a burden or waste of resources, like those working on embedded systems and other low-power applications. To others it’s necessary, abstracting away hardware so that higher-level programming can be done. For most people it’s perhaps not thought of at all. But for a few, the operating system is the most interesting piece of software running on a computer and if you’d like to investigate what makes this often overlooked aspect of computer science interesting, take a look at this course on operating systems from Cornell University.

The operating system itself is called Earth and Grass Operating System because it splits the functionality of the operating system into three separate parts. The Earth layer involves dealing with hardware, the Grass layer involves hardware-independent aspects, and a third application layer implements other key operating system features. It’s built for a RISC-V processor, since that instruction set is completely open source and transparent about what it’s doing. It’s also incredibly small, coming in at around 2000 lines of code. The course covers nine areas, with the first six being core operating system functions and the remaining three covering more advanced operating system concepts.

For understanding the intricacies and sometimes mysterious ways that operating systems work, a course like this can go a long way into unraveling those mysteries and developing a deeper understanding of how it brings the hardware to work for higher-level software. We actually featured this operating system two years ago, before this course was created, which covers this project for those who like to take a more self-directed approach, or simply want a lightweight OS for a RISC-V system.

Mockup of a printed copy of the Little OS Book

One Book To Boot Them All

April 2, 2025 by 19 Comments

Somewhere in the universe, there’s a place that lists every x86 operating system from scratch. Not just some bootloaders, or just a kernel stub, but documentation to build a fully functional, interrupt-handling, multitasking-capable OS. [Erik Helin and Adam Renberg] did just that by documenting every step in The Little Book About OS Development.

This is not your typical dry academic textbook. It’s a hands-on, step-by-step guide aimed at hackers, tinkerers, and developers who want to demystify kernel programming. The book walks you through setting up your environment, bootstrapping your OS, handling interrupts, implementing virtual memory, and even tackling system calls and multitasking. It provides just enough detail to get you started but leaves room for exploration – because, let’s be honest, half the fun is in figuring things out yourself.

Completeness and structure are two things that make this book stand out. Other OS dev guides may give you snippets and leave you to assemble the puzzle yourself. This book documents the entire process, including common pitfalls. If you’ve ever been lost in the weeds of segmentation, paging, or serial I/O, this is the map you need. You can read it online or fetch it as a single 75-page long PDF.

Mockup photo source: Matthieu Dixte

Help Propel The Original ARM OS Into The Future

March 30, 2025 by 33 Comments

We use ARM devices in everything from our microcontroller projects to our laptops, and many of us are aware of the architecture’s humble beginnings in a 1980s Acorn Archimedes computer. ARM processors are not the only survivor from the Archimedes though, its operating system has made it through the decades as well.

RISC OS is a general purpose desktop operating system for ARM platforms that remains useful in 2025, as well as extremely accessible due to a Raspberry Pi port. No software can stand still though, and if RISC OS is to remain relevant it must move with the times. Thus RISC OS Open, the company behind its development, have launched what they call a Moonshots Initiative, moving the OS away from incremental development towards much bolder steps. This is necessary in order for it to support the next generation of ARM architectures.

We like RISC OS here at Hackaday and have kept up to date with its recent developments, but even we as fans can see that it is in part a little dated. From the point of view of RISC OS Open though, they identify support for 64-bit platforms as their highest priority, and to that end they’re looking for developers, funding partners, and community advocates. If that’s you, get in touch with them!

Tactility; The ESP32 Gets Another OS

January 11, 2025 by 11 Comments

Doing the rounds this week is a new operating system for ESP32 microcontrollers, it’s called Tactility, and it comes from [Ken Van Hoeylandt]. It provides a basic operating system level with the ability to run apps from an SD card, and it has the choice of a headless version or an LVGL-based touch UI.

Supported devices so far are some Lillygo and M5Stack boards, with intriguingly, support in the works for the Cheap Yellow Display board that’s caught some attention recently. The term “ESP32” is now a wide one encompassing Tensilica and RISC-V cores and a range of capabilities, so time will tell how flexible it is for all branches of the family.

We find this OS to be interesting, both in its own right and because it joins at least two others trying to do the same thing. There’s [Sprite_TM]’s PocketSprite mini console, and the operating system used by the series of Netherlands hacker camp badges,  We’ll be trying to get a device running it, in order to give you a look at whether it’s suitable for your projects. If it runs well on the cheaper hardware, it could be a winner!

Writing A RISC-V OS From Scratch

January 9, 2025 by 15 Comments

If you read Japanese, you might have seen the book “Design and Implementation of Microkernels” by [Seiya Nuda]. An appendix covers how to write your own operating system for RISC-V in about 1,000 lines of code. Don’t speak Japanese? An English version is available free on the Web and on GitHub.

The author points out that the original Linux kernel wasn’t much bigger (about 8,500 lines). The OS allows for paging, multitasking, a file system, and exception handling. It doesn’t implement interrupt handling, timers, inter-process communication, or handling of multiple processors. But that leaves you with something to do!

The online book covers everything from booting using OpenSBI to building a command line shell. Honestly, we’d have been happier with some interrupt scheme and any sort of crude way to communicate and synchronize across processes, but the 1,000 line limit is draconian.

Since the project uses QEMU as an emulation layer, you don’t even need any special hardware to get started. Truthfully, you probably won’t want to use this for a production project, but for getting a detailed understanding of operating systems or RISC-V programming, it is well worth a look.

If you want something more production-ready, you have choices. Or, stop using an OS at all.

Haiku OS’s Beta 5 Release Brings Us Into A New BeOS Era

October 30, 2024 by 28 Comments

The name BeOS is one which tends to evoke either sighs of nostalgia or blank stares, mostly determined by one’s knowledge of the 1990s operating system scene. Originally released in 1995 by Be Inc., it was featured primarily on the company’s PowerPC-based BeBox computers, as well as being pitched to potential customers including Apple, who was looking for a replacement for MacOS. By then running on both PowerPC and x86-based systems, BeOS remained one of those niche operating systems which even the free Personal Edition (PE) of BeOS Release 5 from 1998 could not change.

As one of the many who downloaded BeOS R5 PE and installed it on a Windows system to have a poke at it, I found it to be a visually charming and quite functional OS, but saw no urgent need to use it instead of Windows 98 SE or 2000. This would appear to have been the general response from the public, as no BeOS revival ensued. Yet even as BeOS floundered and Be Inc. got bought up, sold off and dissected for its parts, a group of fans who wanted to see BeOS live on decided to make their own version. First called OpenBeOS and now Haiku, it’s a fascinating look at a multimedia-centric desktop OS that feels both very 1990s, but also very modern.

With the recent release of the R1 Beta 5 much has been improved, which raises the interesting question of how close Haiku is to becoming a serious desktop OS contender.

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