Comman Operating System

Microsoft Windows

• Microsoft Windows Vista (aka Windows NT 6.0) (codename: Longhorn)
• Windows Server 2003 (aka Windows NT 5.2)
• Microsoft Windows XP (aka Windows NT 5.1) (codename: Whistler)
• Microsoft Windows 2000 (aka Windows NT 5.0)
• Windows NT 4.0, 3.51, 3.5, 3.1
• Windows Me (aka Windows 4.9)
• Windows 98 SE (Second Edition) (aka Windows 4.2)
• Windows 98 (aka Windows 4.1)
• Windows 95 (aka Windows 4.0)

See also: Microsoft

MacOS (Apple Macintosh)

• Mac OS X v10.5 (Leopard) (planned for release in late 2006/early 2007)
• Mac OS X v10.4 (Tiger)
• Mac OS X v10.3 (Panther)
• Mac OS X v10.2 (Jaguar)
• Mac OS X v10.1 (Puma)
• Mac OS X v10.0 (Cheetah)
• Mac OS 9
• Mac OS 8
• Mac OS 7.6 (first officially-named Mac OS)
• System 7 (code-named "Big Bang")
• System Software 6 and earlier

Linux distributions

Linux is an Open Source Operating system

• Ubuntu
• Debian
• MEPIS
• openSUSE
• SUSE Enterprise Linux
• Fedora
• Red Hat Enterprise Linux
• CentOS
• Mandriva
• Xandros
• Linspire (previously known as "LindowsOS")
• Gentoo
• Slackware

External links: Information about Linux Linux article on Wikipedia Home of the Linux kernel

BSD

• DragonFly BSD
• FreeBSD
• PC-BSD
• NetBSD
• OpenBSD

Solaris

• Nexenta
• Solaris

Other

Other operating systems currently in use, and appropriate for specifically targeted web applications and testing, but not considered to be in mainstream use.

• Inferno
• SkyOS
• Digital UNIX (aka Tru64)