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/aosg/ Alternative Operating System General

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Revision as of 21:50, 11 March 2023 by >Alien (→‎Microkernels: Structuring and adding generations)
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Because it's fun to think about what could have been or what might be.

After a thread on /g/, one anon expressed an interest to turn this into a general, and here are some notes to keep to build up a FAQ.

Threads

OP has not yet mastered 4chan posting, so there is as yet no easy way to locate old threads. Manual list:

Some more recent threads also got washed out due to a big cross-board flood. A complete, updated list can always be found at Desuarchive.

List of Notable Alternative Operating Systems

Object Oriented OS

These are written in an object oriented language and everything is an object.

  • http://www.o3one.org/ OZONE is from 2004 and is described by the author as So what makes it object-oriented? Well, just about everything in the kernel is an object. Threads, processes, devices, files, logical names, event flags are all objects. You can assign an logical name to objects. So for example, you could create an event flag and assign a logical name to it. Then other processes can access that event flag and synchronize between them.

Embedded OS

  • https://blackberry.qnx.com/en QNX, a compact micro kernel based OS for embedded use. It used to have a GUI but that is gone, and Photon was replaced by Qt, a QNX engineer even made a desktop-like OS with QNX. While QNX not advertises there is a hobbyst/education program, just contact a QNX sales rep, they can provide you free license. tdelellis at blackberry dot com can probably help you. There are builds for x86/64, arm and even for riscv aswell.
  • https://github.com/MannyPeterson/HeliOS Helios

Operating Systems for Amiga

Plan 9 Family

OS Written in Assembly

Educational OS

Microkernels

The idea is to minimise the kernel and have all services running as services at lower privileges and in a way that the services can be restarted after a crash. Microkernels often work by message passing, and that can cause an overhead. Mach had major performance issues. Some resources:

Microkernels can roughly be divided into 3 families (Mach, GNOSIS, L4) and categories (capability-based, pure vs. impure, traditional vs. direct message passing).

List of microkernels by generation:

  • First generation: RC 4000, Accent, Mach, Exec, MINIX, GNOSIS/KeyKOS, EROS, CapROS
  • Second generation: L3, L4 and reimplementations (Hazelnut, Pistachio, UNSW/NICTA ports, etc.)
  • Third generation: OKL4, Fiasco, seL4, NOVA
  • Exec (Amiga) - the Executive at the deepest level of Amiga OS is a microkernel.
  • Minix is famously microkernel based and the author, Tanenbaum, slogged it out with Linux Torvalds and his decision to make Linux a monolithic kernel rather than a microkernel based OS.
  • Magenta, based on Little Kernel and later renamed into Zircon - this powers Fuchsia.
  • Mach, later GNU Mach - chosen to power HURD.
  • https://drewdevault.com/2022/06/13/helios.html Helios draws inspiration from seL4, and uses a capability-based design for isolation and security. It is used in The Ares Operating System (see above).
  • https://managarm.org/ Managarm is a pragmatic microkernel-based OS with fully asynchronous I/O. (Github)
  • L4 is a family of microkernels

L4 Family of Microkernels

L4 is comprehensibly explained in these lecture notes. There are many members, the most important are:

  • L4 - can run Linux variants such as L4Linux
  • seL4 - high security microkernel
  • L4re AKA Fiasco.OC, used by Kernkonzept.

Emulators

A full install, or even a live CD, is not necessarily needed, sincfe there are emulators.

  • https://copy.sh/v86/ JS VM with lots of OS, including one for Serenity OS.
  • http://simh.trailing-edge.com/ SimH (History Simulator) is a collection of simulators for historically significant or just plain interesting computer hardware and software from the past. Of special note is VAX/VMS where a hobbyist license is provided by Hewlett-Packard Corporation.

Misc

Resources for OSDEV

/aosg/ Book Club

/aosg/ News