what is system software? what is operating system? function of operating system. graphical user interface

1. “OPERATING SYSTEM”
(Presented by: Group 1)
Composed by: Hamidah Rehman, 27
Group members:
Zuha Najeeb, 12
Fatima Ramzan, 21
Humaira Fatima, 13
Sana Nasir, 19
Mahnoor Javed, 42
Sumaiya, 25

2. SYSTEM SOFTWARE
System software consists of the programs that control or maintain the operations of a computer
and its devices.
It is a set of programs that manage the resources of a computer system. System software is a
collection of system programs that perform a variety of functions such as file editing, resource
accounting, storage, memory management etc.
System software is broadly classified into:
 operating systems
 utility programs
Our group will only discuss operating system.

3. OPERATING SYSTEM
An operating system is a set of programs containing instructions that coordinate all the
activities among computer hardware resources.
Operating system is an integrated set of specialized programs used to manage
overall resources and operations of the computer. It is a program that acts as an
interface between the software and the computer hardware.
Different sizes of computers typically use different operating systems. The
operating system that a computer uses sometimes is called the platform. A
cross-platform program is one that runs the same on multiple operating systems.

4. FUNCTIONS OF OPERATING
SYSTEM
Most operating systems perform similar functions that include:
• Starting a computer
• Providing a user interface
• Managing programs
• Managing memory
• Scheduling jobs
• Configuring devices
• Establishing an internet connection
• Monitoring performance
• Providing file management utilities

5. OPERATING SYSTEM
FUNCTIONS
Starting a computer:
Booting is the process of starting or restarting a computer.
There are 2 types of booting:
• Cold booting: when the computer is started after having been switched off.
• Warm booting: when the operating system alone is restarted (without being switched off)
after a crash or freeze.
Each time you boot a computer, the kernel and other frequently used operating
system instructions are loaded or copied from the hard disk into the computer’s
memory.

6.  STARTING A COMPUTER
The kernel is the core of an operating system that manages memory
and devices, maintains the computer’s clock, starts applications and
assigns the computer’s resources such as devices, programs, data and
information.
The boot process, however, is similar for large and small computers.

7.  PROVIDING A USER
INTERFACE
A user interface (UI) controls how you enter data and instructions and how information is
displayed on the screen.
It refers to the part of an operating system, program or device that allows a user to
enter and receive information.
Two types of user interfaces are:
• Command-line interface
• Graphical user interface
Operating system sometimes use a combination of these interfaces to define how a
user interacts with a computer.

8. 1. COMMAND-LINE INTERFACE
In a command-line interface, a user types commands or presses special keys on the keyboard to
enter data and instructions.
Users work with command line interface to configure devices, manage system
resources and troubleshoot network connections. Command-line interfaces are
often difficult to use because they require exact spelling, grammar and
punctuation.
A program which handles the interface is called a command language interpreter
or shell (computing).

10. 2. GRAPHICAL USER INTERFACE
With a graphical user interface(GUI), user interact with menus and visual images such
as buttons and other graphical objects to issue commands.
Window Vista offers two different GUI’s depending on your hardware
configuration.
• Computers with less than 1GB of RAM work with the Windows Vista Basic
interface.
• Computers with more than 1GB of RAM work with the Window Aero
interface.

12.  MANAGING PROGRAMS
Some operating systems support a single user and only one running program at a
time while others support thousands of users running multiple programs.
• A single tasking operating system allows only one user to run one program at
a time, e.g. PDAs, smart phones and other small computing devices.
• A multi tasking operating system allows a single user to work on two or more
programs that reside in memory at the same time, e.g. an e-mail and web browser
open at all times while working with word processing or graphics.
When a computer is running multiple programs concurrently, the active program is
in the foreground while the other programs that are not running, are in the
background.
You can easily switch between background and foreground programs.

13.  MANAGING MEMORY
The purpose of memory management is to optimize the use of RAM.
RAM consists of one or more chips on the motherboard that hold items such as data
and instructions while the processor interprets and execute them. The operating system
allocates or assigns data and instructions to an area of memory while they are being
processed.
Virtual memory is a concept in which the operating system allocates a portion of a storage medium,
usually hard disk, to function as additional RAM. It is slower than RAM.
The operating system uses an area of hard disk for virtual memory in which it swaps
data, information and instructions between memory and storage.
This technique of swapping items between memory and storage is called paging.

14.  SCHEDULING JOBS
Jobs include receiving data from an input device, processing instructions, sending information to an
output device and transferring items from storage to memory and from memory to storage. It is an
operation the processor manages.
Sometimes, a device already may be busy processing one job when it receives a
second job. This occurs because the processor operates at a much faster rate of
speed than peripheral devices.
For example,
If the processor sends five print jobs to a printer, the printer can print only one
document at a time and store as many documents as its memory can handle.
While waiting for devices to become idle, the operating system places items in
buffers.

15.  SCHEDULING JOBS
A buffer is a segment of memory or storage in which items are placed while waiting to be
transferred from an input device or to an output device.
The operating system commonly uses buffers with print jobs. This process, called
spooling, sends print jobs to a buffer instead of sending them immediately to the
printer. The buffer holds the information waiting to print while the printer prints
from the buffer at its own rate of speed. By spooling print jobs to a buffer, the
processor can continue interpreting and executing instructions while the printer
prints. This allows users to work on the computer for other tasks while a printer is
printing. Multiple print jobs line up in a queue in the buffer.

16.  CONFIGURING DEVICES
A driver is a program that tells the operating system how to communicate with a specific device.
A driver provides a software interface to hardware devices, enabling operating systems
and other computer programs to access hardware functions without needing to know
precise details about the hardware being used.
Every device, whether it be a printer, disk drive, or keyboard, must have a driver
program. Many drivers, such as the keyboard driver, come with the operating system.
When you boot a computer, the operating system loads each device’s driver.
For other devices, you may need to load a new driver when you connect the device to
your computer. Like if you attach a new device to a computer, such as a printer or
scanner, its driver must be installed before you can use the device.
You can even install the drivers from the CD provided with the purchased device.

17.  CONFIGURING DEVICES
Today, many devices and operating systems support Plug and Play.
Plug and Play gives users the ability to plug a device into a computer and have the computer
recognize that the device is there.
The user doesn't have to tell the computer.
For example,
A video card or hard drive may be a Plug and Play device, meaning the computer
will recognize it as soon as it is installed.

18.  ESTABLISHING AN INTERNET
CONNECTION
Operating systems typically provide a means to establish Internet connections.
For example,
Windows Vista includes a Connect to a network wizard that guides users through
the process of setting up a connection between a computer and an Internet
service provider.
The basic requirements for connecting to the Internet are a computer device, a
working Internet line and the right modem for that Internet line. In addition,
software programs such as Internet browsers, email clients, Usenet clients and
other special applications are needed in order to access the Internet.

19.  MONITORING PERFORMANCE
A performance monitor is a program that assesses and reports information about various
computer resources and devices.
Operating systems typically contain a performance monitor. The information in
performance reports helps users and administrators identify a problem with
resources so they can try to resolve any problems.
For example,
If a computer is running extremely slow, the performance monitor may determine
that the computer’s memory is being used to its maximum. Thus you might
consider installing additional memory in the computer.

20.  PROVIDING FILE MANAGEMENT
AND OTHER UTILITIES
Operating system often provide users with the capability of
managing files, searching for files, viewing images, securing
a computer from unauthorized access, uninstalling
programs, scanning disks, diagnosing problems, backing up
files and disks and setting up screen savers.

21.  CONTROLLING A NETWORK
A network operating system is an operating system that organizes and coordinates how
multiple users access and share resources on a network.
Some operating system have network features built into them while in other cases,
the network OS is a set of programs separate from the operating system on the
client computers that access the network.
When not connected to the network, the client computers use their own operating
system. When connected to the network, the network OS may assume some of
the operating system functions.
The network administrator uses the network OS to add and removes users,
computers and other devices to and from the network.

22.  ADMINISTERING SECURITY
The network administrator uses the network OS to establish permissions to
resources. These permissions define who can access certain resources and when
they can access those resources. For each user, the network administrator
establishes a user account, which enables a user to access or log on to a
computer or a network. Each user account typically consists of a user name and
password.
A user name or user ID is a unique combination of characters, such as letters
of the alphabet or numbers, that identifies one specific user.

23.  ADMINISTERING SECURITY
Some operating systems allow the network administrator to assign passwords to
file and commands, restricting access to only authorized users. To prevent
unauthorized users from accessing computer resources, the users use passwords.
A password is a private combination of characters associated with the user name that allows
access to certain computer resources.
To protect sensitive data and information as it travels over the network, a network
operating system may encrypt it.
Encryption is the process of encoding data and information into an unreadable form.
When an authorized user attempts to read the data, it automatically is decrypted,
or converted back into a readable form.

24. OPERATING SYSTEM
UTILITY PROGRAMS
A utility program, also called a utility, helps to manage, maintain and control computer resources.
It is a small program that provides an addition to the capabilities provided by the
operating system. In some usages, a utility is a special and nonessential part of the
operating system. It is used to support the computer infrastructure.
Examples of utility programs include:
• Antivirus software
• Backup software
• Disk tools etc.
Following slides will briefly discuss some of the utilities.

25. 1. FILE MANAGER
A file manager is a software program that helps a user manage all the files on their computer.
For example, all file managers allow the user to view, organize, edit, rename,
copy, move and delete the files on their computer storage devices.
 With recent version of Microsoft Windows, Windows Explorer is
considered the default manager.
 With Apple computers, Finder is considered the default manager.

26. 2. SEARCH UTILITY
A search utility is a program that attempts to locate a file on your computer .
Search utilities can look through documents, pictures, music and other
files.
Window vista has a built-in search utility. All the explorer windows, as
well as the start menu, contain a search box where you enter the
search criteria.

27. 3. IMAGE VIEWER
An image viewer or image browser is a computer program that display stored graphical images.
With an image viewer, users can see images without having to open them in a paint or
image editing program. Image viewer of Window Vista is called Windows Photo
Gallery.
Typical features of image viewers are:
• Full screen display
• Zooming and rotation
• Slideshow
• Printing
• Photo editors etc.

28. 4. PERSONAL FIREWALL
A personal firewall is a utility that detects and protects a personal computer from
unauthorized intrusions.
It constantly monitor all transmissions to and from a computer and protect your
computer from outside attempts to control or gain access to your computer.
Because when connected to an internet, your computer is vulnerable to attacks
from a hacker. A hacker is someone who tries to access a computer or network illegally.
Firewall of Window Vista is called Windows Firewall. It is easy to access and
configure. Moreover, you can also purchase a stand-alone personal firewall utility
or a hardware firewall for additional protection.

29. 5.UNINSTALLER
An uninstaller is a utility that removes a program, as well as any associated entries in the
system files.
It allows a user to safely uninstall an application by running a program following
a series of prompts that warn users about the application’s removal. The
uninstaller deletes files and folders from the hard disk as well as removes
program entries from the system files.
Additionally, various uninstallers may be downloaded as separate applications.

30. 6. DISK SCANNER
A disk scanner is a utility that searches for and removes unnecessary files.
It is able to scan any disk which you see in Windows. The utility first searches
and analyzes the hard drive for files that are no longer of any use and then
removes the unnecessary files.
Window Vista includes a disk scanner utility called Disk Cleanup. It is a
computer maintenance utility included in Microsoft Windows designed to free
up disk space on a computer’s hard drive.

31. 7. DISK DEFRAGMENTER
A disk defragmenter is a utility that recognizes the file and unused space on a computer’s hard
disk so the operating system accesses data more quickly and programs run faster.
Disk defragmenter rearranges fragmented data so your disks and drives can work
more efficiently. Disk defragmenter runs on a schedule, but you can also analyze
and defragment your disks and drives manually.
Fragmentation slows down disk access and thus the performance of the entire
computer. Defragmenting the disk, or recognizing it so the files are stored in
contiguous (next to each other) sectors, solves this problem.

32. 8. DIAGNOSTIC UTILITY
A diagnostic utility compiles technical information about your computer’s
hardware and certain system software programs and then prepares a report
outlining any identified problems.
Information in the report assists technical support staff in remedying
any problems.

33. 9. BACKUP UTILITY
A backup utility allows a user to copy, or backup selected files or an entire hard disk to another
storage medium such as CD, DVD, external hard disk , tape or USB flash drive.
Many backup programs compress or shrink the size of files during the backup
process. By compressing the files, the backup program requires less storage space
for the backup files than for the original files. Because they are compressed, you
usually can’t use backup files in their backed up form. In the event you need to use
a restore program that reverses the process and returns backed up files to their
original form.

34. 10. SCREEN SAVER
A screen saver is a utility that causes a display device’s screen to show a moving image or blank
screen if no keyboard or mouse activity occurs for a specified time.
When you press a key on the keyboard or move the mouse, the screen saver
disappears and the screen saver returns to the previous state.
Screen savers were originally developed to prevent a problem called ghosting, in
which images could be permanently etched on a monitor's screen.
Screensavers are also popular for security, business and entertainment purposes

35. “QUIZ”
1. What are the two types of a system software?
2. Define operating system.
3. What is a user name or user ID?
4. How you can define password?
5. What is a utility program?