This is a directory of active operating systems.  If there are any that are missing from this list or close down please email me and let me know.   These are primarily consumer level operating systems but I will be adding additional sections in the future.

There are currently 90+ Operating Systems on this list and does not include different types for a single manufacture at this point.  I will be updating it to include the other types such as Server OS’s in the future.

Cloud Computing

AMD Fusion Render Cloud (Still in development)

Cassatt

CherryPal

Citrix

Cloudo

EyeOS

G.ho.st (ghost)

Go Anywhere (Symantec)

gOS (Good OS)

iCloud (Xerion)

Jooce

Independent

AROS (AmigaOS Clone)

Haiku (BeOS Clone)

LoseThos (Server OS x64 only)

Mac OS X Leopard

MenuetOS

Microsoft Windows

ReactOS (Windows Clone)

Whitix

Unix\Linux Based

4bak (Forensics/Backup)

64 Studio (Digital Media Desktop)

Arch Linux

AbulÉdu (French)

Agnula

BackTrack (Wireless Security)

Bee Linux (Algerian – French)

Buildix

Baltix

CentOS

CentServer

CrunchEee (Netbook)

Dmn Small Linux

Debian

Debris

Dreamlinux

Easy Peasy (Netbooks)

eBox

e-Swecha (India)

Elive

Fedora

Finnix (Live Disk)

GeeXboX (Home Theatre PC)

Gentoo

Gibraltar (Embedded Linux)

gOS (Good OS)

Grml

HyperSpace (Instant-On)

Incognito (Privacy Live CD)

Jaris (Japanese)

Jolicloud (Netbook)

Kalango

Kanotix

KnoppMyth

Knoppix

Kubuntu

Kuki (Netbook)

Kurumin (Portuguese)

Leaf (Embedded Linux)

Linex (Spanish)

Linux4One (Only supports Acer Aspire Netbook)

LinuxEllSchool

Linux Mint

LiMux

Linspire

Live-Linux-Gamers

Mac-On-Stick

Mandriva

Mepis

Moblin (Netbook and Mobile Internet Devices)

NepaLinux

Nexenta

NimbleX

OpenGEU

OpenSolaris

OpenSuse

Pardus

PCLinuxOS

PingOO (French)

ProgeX

Puppy Linux

Pure:Dyne (Live CD for Audio and Video Processing)

Quimo 4 Kids

Rebuntu Linux

Red Hat

rxart

SecurPC

Sidux

Skolelinux

Slackware

Slax

Splashtop (instant-on)

Suse (Open)

Suse (Novell)

SymphonyOne

The Chakra Project

Tiny Core Linux (10 MB)

Toutou Linux (French)

Trisquel

Tuquito (Spanish)

Ubuntu

Ubuntu Privacy Remix (Live disk for Privacy)

Untangle (Network Control)

Xandros (formerly Corel)

Xebian (For Xbox)

Zorin OS

Berkeley Software Distribution (BSD)

DesktopBSD

DragonFlyBSD

FreeBSD

FreeNas (NAS Server)

Jibbed

NetBSD

OpenBSD

PC-BSD

Government/Security

Integrity 178B (Green Hills Software)

LynuxWorks

PikeOS (Sysgo)

Deos (DDC-I)

Mobile Phone

Apple iPhone

BREW

Garnet (formerly Palm 5)

Google Android

JavaFX Mobile (Sun)

Palm Pre webOS

RIM (Blackberry)

Symbian

Windows Mobile

Dos Clones

BOS

DrDos

RTKernel

This list was compiled entirely of my own research.  If you replicate this list in part or in whole please give credit to OS Attack.