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1.  Network Operating System runs on a
server
 provides server the capability to manage
data, users, groups, security, applications,
and other networking functions.
 The primary purpose of the network
operating system is to allow shared file
and printer access among multiple
computers in a network


2. Examples of network operating systems are
Microsoft Windows Server 2003,
 Microsoft Windows Server 2008,
 UNIX,
 Linux,
 Mac OS X,
 Novell NetWare.

3.  Is defined as a data processing system.
 Real time processing is always on line
 whereas on line system need not be real
time.
 The time taken by the system to respond
to an input and display of required
updated information is termed as
RESPONSE TIME.


4.  Therefore, response time is very less as
compared to the online processing.
 used when there are rigid time
requirements on the operation of a
processor or the flow of data.
 can be used as a control device in a
dedicated application.

5. Real-time operating system has well-
defined, fixed time constraints otherwise
system will fail.
 For example scientific experiments,
medical imaging systems, industrial
control systems, weapon systems, robots,
and home-appliance controllers, Air
traffic control system etc.

6. Provides the User Interface.
Load Application programs.
Coordinates how programs work with the
CPU, RAM, Keyboard, mouse, printer and
other hardware.

7. The interface provided by the operating system
to the user to interact with a set of items on the
screen is called User Interface.
Types
1) Command line interface
2) Graphical User interface ( GUI)

8. An environment that uses typewritten
commands to execute tasks and process data.
User interacts with the command line by
typing strings of characters at a prompt on the
screen.
Example: MS-DOS and PC-DOS.

9.  An interface that provides different items
(icons) to select different programs and which
is visible as a Graphical screen is known as
Graphical interface.
 Example: Windows, OS/2, Macintosh and
some versions of Unix.
 First GUI interface was introduced in 1984 for
Mac systems.

10. Parts of a GUI
 Desktop
 Running programs
 Menus
 Dialog boxes

11. It provides a consistent interface between the
program and the user.
provide the interface between programs and
other computer recourses like printer, CPU or
other programs.
System Calls: The instructions that request
services from the operating system.

12. Saving the contents of a file to a disk for
permanent storage.
Reading the contents of a file from the disk into
memory.
Sending a document to the printer and activate the
printer.
Providing recources that let you copy or move
data from one document to other

13.  Allocating RAM among various programs
that you may have open- Multitasking
 Recognizing keystrokes or mouse clicks and
displaying characters or graphics on the
screen


14.  When programs run, they need to use the
computer's memory, monitor, disk drives, and
other devices, such as a printer.
 The operating system is the intermediary
between programs and hardware.

15. In a computer network, the operating
system also mediates between your
computer and other devices on the
network.

16.  The O.S responds to requests to use
memory and other devices,
 keeps track of which programs have access
to which devices,
 coordinates everything the hardware does.
 so that various activities do not overlap
causing the computer to become confused
and stop working.

17.  The operating system uses interrupt
requests (IRQs) to help the CPU coordinate
processes.

18. Operating
System
OS sends interrupt
request to the CPU
OS tells the CPU to go to
the disk drive to retrieve
the names of files in a
folder
CPU receives the
names of the files
in the folder
Contents are
highlighted in
the monitor

19. using interrupts,
• the os often provides programs for
working with special devices such as
printers.
• These programs arc called drivers because
 they allow the O.S and other programs to
activate and use “driver"—the hardware
device.


20. • Most new software you buy will work
with your printer; monitor; and other
equipment without requiring you to install
special drivers.
