Welcome! Funtoo Linux (distrowatch) is a community-developed Linux meta-distribution based upon Gentoo Linux. Funtoo Linux is optimized for the best possible performance on the latest Intel and AMD hardware. Funtoo is led by Daniel Robbins, the creator of Gentoo Linux, and actively developed by the Funtoo community.
Funtoo does not use systemd, but OpenRC https://www.funtoo.org/FAQ:Do_You_Support_Systemd
HelenOS is a portable microkernel-based multiserver operating system designed and implemented from scratch. It decomposes key operating system functionality such as file systems, networking, device drivers and graphical user interface into a collection of fine-grained user space components that interact with each other via message passing. A failure or crash of one component does not directly harm others. HelenOS is therefore flexible, modular, extensible, fault tolerant and easy to understand.
Rump kernels enable you to build the software stack you need without forcing you to reinvent the wheels. The key observation is that a software stack needs driver-like components which are conventionally tightly-knit into operating systems — even if you do not desire the limitations and infrastructure overhead of a given OS, you do need drivers.
Found on Kooda's blog https://www.upyum.com/en/post/2.xhtml
NuttX is a real-time operating system (RTOS) with an emphasis on standards compliance and small footprint. Scalable from 8-bit to 32-bit microcontroller environments, the primary governing standards in NuttX are Posix and ANSI standards. Additional standard APIs from Unix and other common RTOS's (such as VxWorks) are adopted for functionality not available under these standards, or for functionality that is not appropriate for deeply-embedded environments (such as fork()).
LNG is an operating system primarly for the good old Commodore64 home-computer. There also is a native version for the successor Commodore128. Ports to other 6502/6510 driven 8Bit Computers are possible but not yet started. LUnix started in 1993 and reached the internet in 1994. In 1997 LUnix0.1 was rewritten from scratch, the result is LNG.
This list is an exploration of the world of UNIX®, including UNIX history, the relevance of UNIX today, and lists select awesome UNIX and UNIX-like projects. This list also contains resources for UNIX standards, programming, communities, and free software.
Deploy and Manage Your Containers in the Next-Generation Container OS
Use immutable infrastructure to deploy and scale your containerized applications. Project Atomic mainly comprises Atomic Host, Atomic Workstation, and various container tooling. cloud native platforms.
This is the announcement, more details can be found on https://github.com/EtchedPixels/FUZIX
Note that it is not limited to 8-bit processors: core code can be built for 6502, 6809, 68000, 8086, MSP430, pdp11 and Z80/Z180.