Operating Systems: An operating system is a set of programs that manage computer hardware resources and provide common services for application software. There are following kinds related to operating system
Real-time Operating Systems
Single User/ Multitasking Operating Systems
Multi User / Multitasking Operating Systems
Providing a User Interface
Graphical User Interface
Enhancing an Operating Systems
PC Operating Systems
DOS
Windows NT, Windows 9x, Windows XP
UNIX
Linux, Macintosh Operating Systems
Networking Operating Systems
Embedded Operating Systems
Migration Of Operating-System Concepts And Features