There are different types of operating systems and scientists have categorized these systems according to technology,ownership,license, usage and characteristics. You can find details as below:

Macintosh Operating Systems:

· System Software 1

· System Software 2

· System Software 3

· System Software 4

· System Software 5

· System 6

· System 7

· Mac OS 8

· Mac OS 9

Unix-like

· A/UX

· Darwin

· MkLinux

· Mac OS X v10.0 (aka “Cheetah”)

· Mac OS X v10.1 (aka “Puma”)

· Mac OS X v10.2 (aka “Jaguar”)

· Mac OS X v10.3 (aka “Panther”)

· Mac OS X v10.4 (aka “Tiger”)

· Mac OS X v10.5 (aka “Leopard”)

· Mac OS X v10.6 (aka “Snow Leopard”)

· Mac OS X Server

Microsoft

· Xenix (licensed version of Unix)

· MSX-DOS (developed by MS Japan for the MSX 8-bit computer)

· MS-DOS

· Windows CE (OS for handhelds)

· Windows CE 3.0

· Windows Mobile

· Windows CE 5.0

· Windows CE 6.0

· Windows Mobile 5.0

· Windows Mobile 6.0

· Windows Mobile 6.1

· Windows Mobile 6.5

· DOS-based Windows

· Windows 1.0

· Windows 2.0 (Windows 2)

· Windows 3.0 (Windows 3 )

· Windows 3.1x

· Windows 3.2 (Chinese Version)

· Windows 9x (Windows 4 family)

· Windows 95

· Windows 98 (Nickname: Memphis)

· Windows Millennium Edition

· OS/2

· Windows NT

· Windows NT 3.1 (OS/2 3.0)

· Windows NT 3.5

· Windows NT 3.51

· Windows NT 4

· Windows 2000

· Windows Fundamentals for Legacy PCs

· Windows XP

· Windows Server 2003(codename: Whistler Server)

· Windows Vista (Windows NT 6.0 – Windows 6) (codename: Longhorn)

· Windows Home Server

· Windows Server 2008 (Windows NT 6.0 – Windows 6)

· Windows 7 (previously codenamed Blackcomb, then Vienna)

· Windows Pre-installation Environment (Win-PE)

· Singularity – A research operating system written mostly in managed code (C#)

· Midori – A managed code operating system