An operating system coordinates activities between computer hardware, provides means for users to communicate with the computer and software, and manages computer resources. There are multi-user operating systems that allow multiple users to access a computer at once and single-user systems that allow one user but multiple programs. Operating systems features include time sharing to allocate portions of time to jobs, multiprocessing to run programs simultaneously, distributed systems to share jobs across networked computers, and real-time systems to perform tasks within time constraints. Common operating systems include Windows, Mac OS, and the goals of operating systems are efficient hardware use and easy resource access.

1. COMPUTER OPERATING SYSTEM
Presented By : Misbah Javid

2. OPERATING SYSTEM(OS)
 An operating system is a set of programs that coordinates
all the activities among computer hardware devices.
 It provides means for users to communicate with the
computer and other software.
 An operating system (OS) is a collection of software that
manages computer hardware resources and provides
common services for computer programs.

3. TYPES OF OPERATING SYSTEMS
• Multi-user
A multi-user operating system allows multiple users
to access a computer system at the same time.
• Single-user
Single-user operating systems have only one user
but may allow multiple programs to run at the same time.

4. CHARACTERISTICS OF OPERATING SYSTEM
 Time Sharing- Multiprogramming brought the idea of time
sharing: resources could be shared between different jobs, with each
job being allocated a portion of time to use a resource. Because a
computer is much faster than a human, time sharing is hidden from
the user—each user has the impression that the whole system is
serving them exclusively.
 Multiprocessing - In multiprocessing many programs can
process at the same time.

5. CHARACTERISTICS OF OPERATING SYSTEM
 Distributed Systems- A job that was previously done on
one computer can now be shared between computers
that may be thousands of miles apart.
 Real Time Systems - A real-time system is expected to
do a task within a specific time constraint.

6. USAGE OF OPERATING SYSTEM
• Many of today's computer use Window vista or Window
XP Which are two of Microsoft's operating
system(Dell,Hp,Intel,IBM,Compact).
• Mac OS X (Apple's) operating system.

7. GOALS OF OPERATING SYSTEM
Two major design goals for an operating system are:
 Efficient use of hardware.
 Ease use of resources.