= Operating Systems ZOO =

A semi-structured list of significant (for one reason or another) operating systems. The purpose of this list is to have a permanent source of references when doing any type of comparison, related work survey, etc. The fact that an operating system is listed (or is not listed) in this list has no implicit implication for HelenOS and signifies no specific relation.

== Monolithic Systems ==
* GNU/Linux
* Solaris
  * OpenSolaris
  * illumos
* Windows NT
  * ReactOS
* Plan 9
  * see Inferno
* OS/2
  * eComStation
* FreeBSD
* OpenBSD
* NetBSD
  * see rump kernel
* MidnightBSD
* TrustedBSD
* AmigaOS
  * AtheOS
    * Syllable
* BeOS
  * Haiku
* SkyOS

== Monolithic Systems (written in assembler) ==
* MenuetOS
* KolibriOS
* see BareMetal

== Microkernel Hybrid ==
* OS X
  * iOS
  * XNU
  * Darwin
* Dragonfly BSD

== Microkernel Multiserver (mostly) ==
* MINIX 3
* GNU Hurd
* QNX
  * Neutrino

== The L4 Family of Microkernels ==
* L3
* seL4

== Virtual Machine-Based ==
* Inferno
* Singularity

== Exokernels / Unikernels ==
* rump kernel
* BareMetal
* OSv

== Hypervisors ==
* Xen
* NOVA

== Operating System Frameworks ==
* Genode

== Real-Time (single image monolithic) ==
* RTEMS