Transcript Operating System Powerpoint File

Chapter 1: Operating Systems
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What are Operating Systems?
The operating system (OS) is a program
that, after being initially loaded into the
computer by a boot program, manages all the
other programs/applications.
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Examples of OS:
Windows 7
Windows Vista
Windows Server 2003
Linux
Mac OS X
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Functions of the OS:
1. Provides a user interface
2. Device management (input/output control)
3. Security (e.g. log on, passwords, etc.)
4. Handles interrupts (is an asynchronous signal from
hardware indicating the need for attention or a
synchronous event in software indicating the need for a
change in execution.)
5. Spooling (is a process in which data is temporarily held to
be used and executed by a device, program or the
system. Data is sent to and stored in memory or other
volatile storage until the program or computer requests it
for execution.)
6. Memory management
7. Multitasking
8. Batch processing
9. Multiprogramming
10. Error reporting and handling
11. Loading and running software
12. Processor management
13. Maintain user accounts
14. Utilities (such as copy, save, re-name, etc.)
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What are Command Line Interfaces (CLIs)?
CLI is a user interface common to MS-DOS.
The user sees the command line on the
monitor and a prompt that is waiting to
accept instructions from the user. The user
types in the command, the computer acts on
that command and then issues a new prompt
for the next instruction from the user.
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What is Graphical User Interface (GUI)?
It refers to the graphical interface of a
computer that allows users to click and drag
objects with a mouse instead of entering text
at a command line. Two of the most popular
operating systems, Windows and the Mac OS,
are GUI-based.
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What are icons?
An icon is a small picture or symbol on a
graphical user interface (GUI) that represents
a program (or command), file, directory (also
called a folder) or device (such as a hard disk
or floppy).
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What is WIMP?
Windows Icons Menu Pointing Device
interfaces allow the user to exchange
information with the computer by means of a
pointing device (often a mouse) and a video
monitor. The pointing device referred to in
the WIMP acronym enables the user to select
images, words, and the like on the display
screen.
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Pc/Desktop Computers
Personal
Computers
(PC)
use
a
microprocessor and are designed for
individual use, as by a person in an office or
at home or school.
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Advantages of a PC:
1. Low budget computers.
2. Better specification and can be eventually
upgraded.
3. Good cooling system compared to other
computers.
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Disadvantages of a PC:
1. Not portable.
2. Takes a lot of space due to cables, wirings
and additional hardware.
3. Need to copy files to work away from
office or home.
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Laptops
A laptop computer is a portable personal
computer light and small enough to sit on a
person's lap.
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Advantages of a Laptop:
1. Portable.
2. No need for extra wirings.
3. No need for additional hardware such as
modems as Wi-Fi can be used.
4. Can be connected to any multimedia
systems.
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Disadvantages of a Laptop:
1. Can be lost or stolen.
2. Users need to constantly charge them as
they have limited battery as resource.
3. Cooling system is difficult to be dealt with
in a laptop.
4. Users can face difficulty in using keyboard
and pointing devices in a laptop.
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Net books:
A net book is a small, light, low-power
notebook computer that has less processing
power than a full-sized laptop but is still
suitable for word processing, running a Web
browser and connecting wirelessly to the
Internet.
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Advantages of a Net book:
1. Portable.
2. No need for extra wirings.
3. No need for additional hardware such as
modems as Wi-Fi can be used.
4. Can be connected to any multimedia
systems.
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Disadvantages of a Net book:
1. Can be lost or stolen.
2. Users need to constantly charge them as
they have limited battery as resource.
3. Cooling system is difficult to be dealt with
in a net book.
4. Users can face difficulty in using keyboard
and pointing devices in a net book.
5. Do not have optical drives.
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Personal Digital Assistants (PDA):
Any small mobile hand-held device that
provides computing and information storage
and retrieval capabilities for personal or
business use, often for keeping schedule
calendars and address book information
handy.
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Advantages of a PDA:
1. Can be used anywhere because of their
portability.
2. More light weight than a laptop.
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Disadvantages of a PDA:
1. Difficult to enter text rapidly.
2. Limited capabilities due to restraints in
software.
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Mainframe Computers:
A very large and expensive computer
capable of supporting hundreds, or even
thousands, of users simultaneously.
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Advantages of a Mainframe:
1. Can be used to do very large jobs.
2. Supports thousands of transactions per
second.
3. More reliable and secure than clientserver networks.
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Disadvantages of a Mainframe:
1. Dedicated staffs are needed to run the
system.
2. They can take up a lot of space and
require
dedicated
environmental
management, for example, cooling
systems.
3. Initial start-up costs can be high.
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Homework:
1. Give four functions carried out by a
typical operating system.
2. State two file management tasks that
would be carried out by an operating
system.
3. Explain how the operating system will
deal with errors that occur whilst a program
is running.
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