ICT Grade 10 - Operating Systems english

Introduction to Operating Systems

A Computer consists of

                                hardware,

                                firmware

                                software.

                                Liveware

Hardware

Any physical component of a computer system with a definite shape is called a hardware.

Examples             mouse, keyboard, display unit, hard disk, speaker, printer etc.

Firmware

•   The booting instructions stored in the ROM (Read Only Memory) are called firmware.
•   The initial text information displayed on the screen are displayed by firmware.

How the initial operations of a computer are performed

-      When the user powers up the computer the CPU (Central Processing Unit) activates the BIOS (Basic Input Output System).

-      The first program activated is POST (Power On Self-Test). Using the CMOS (Complementary Metal Oxide Semiconductor) memory  this checks all the hardware and confirms that all are functioning properly.

-      After that it reads the MBR (Master Boot Record) in boot drive in accordance with the firmware ‘bootstrap loader’ which is provided by the computer manufacturer.

-      Then the computer loads in the Operating System in boot drive to the RAM (Random Access Memory)

-      Once this is performed the Operating System takes over the control of the computer and displays a user interface to the user.

This whole process is called booting which means that an Operating System is loaded into the RAM

Software

Software  is a set of instructions given to the computer to perform some activity using a computer. There are many types of software.

The Classification of Software

 

                                                                                                                                                                                                            

System Software

§  Operating System – This perform the  functions of a computer by managing the hardware and software .

how the system software and application software interact with the hardware.

 

§  Utility Software – These are used to manage and analyze the software in the computer.

-          Utility software helps in managing the resources of the computer

-          The utility software differ from the application software in their complexity and operational activities

§  Language Translators - A computer program (software) is made up by using a set of instruction codes. These instructions are written in high level languages which are very close to the human languages. These high level languages are translated into machine language by language translators.

Application Software

The application software which runs on the Operating System is used to carry out computer based activities of the user such as creating documents, mathematical functions, data entry and, computer games.

Interaction between the user and the computer

 

                                                                                                                                                                    Introduction to several Operating Systems

1. Microsoft Windows Operating System

-      Introduced by Microsoft is

-          Users have to pay for software license (proprietary software)

-           very popular around the world and is available in many different editions

Ex           ……………………………………………………………………………………………………………………………………………………………………….

-           There is a edition for smart phones, tablets and  Serve etc.
                Ex MS Windows Server

2. Apple Mac Operating System

-          This was developed by Apple Incorporation. Also  called Apple Macintosh

-           This Operating System is also a proprietary software which requires payment for license

3. Ubuntu Operating System

-          Ubuntu has been developed based on Linux Operating System

-           ThisOperating System is available free of charge. (Free and Open Source Software.)

4. Android Operating System

-          Android operating system is developed by Google.

-          This is mainly used for the mobile devices.

-           This is also a Free and Open Source Software.

5. Hanthana Linux

-          This operating system is developed based on Linux operating system

-           Can be downloaded free of charge at www.hanthana.org

Benefits of use of Free and Open Source Software

…………………………………………………………………………………………………………………………….. ………………………………………………………………………………………………………………………………

Types of Operating Systems

Based on the functionality the Operating System can be classified as:

1. Single user operating system - The OS which provides service to one person at a time is called

              Example - MS Dos Operating System

2. Multi user operating system

• The OS  allows multiple users to use a system is simultaneously
• Commonly used in Mainframe or Server computer where several users are connected to a computer system simultaneously.

Example - Linux, Windows server

3. Multi-tasking operating system

• The OS which allows to run multiple process at the same time 

§   A single user can run multiple operations (tasks) at the same time on this type of operating system.

Example - Windows 7, Windows 8, Ubuntu, Mac Operating System

4. Real time operating system

• OS which gives the output in real time without any observable delays.
• mostly utilized in ATM end points.
• Also these kind of Operating Systems are installed in scientific devices and small gadgets.
• These Operating Systems are specifically designed for particular devices.

Services of an Operating System

There are two main services performed by an operating system

1. Managing the hardware of a computer

2. Providing user interface

1) Managing the Hardware of a computer

                                Hardware of a computer are managed by using the following processes;

i. Process Management

ii. Memory Management

iii. Device Management

iv. File Management

v. Security Management

vi.Network Management

Process Management

Process  - Running computer program or part of the program called as a process. All the activities in a computer run as -           either a single process

              - or a multiple processes

Resource management activities such as

- allocation of CPU time,

                - allocation of memory,

                - allocation of input output devices of  each process

are managed under the process management of Operating System.

Memory Management

-          Memory process makes sure that enough memory is allocated for each process and it also makes sure that the memory is freed once a particular process ends.

-          Operating System utilizes both the Primary Memory (RAM) and the Secondary Memory efficiently in order to manage the memory for various processes.

Device Management

-          OS is responsible for the management of several peripheral devices connected to a computer system.

-          Device controllers are used to control the peripheral devices and Device drivers are used to control software

-          Today there are devices which work once they are connected (plug and play). Which mean the relevant device drivers are installed automatically once the device is connected to the computer for the first time.  Therefore nowadays the process of installation of the device driver has become easy.

 File Management

-          We can save data in files and we keep the files within the folders in order to manage methodically. The Operating System to manage the files and folders.

-           File and folder management includes

 file properties                           file operations                                   file access                            file systems.

-          Some of the services performed by the Operating System in file management are listed below:

•       Making new files and saving them at suitable places

•       Deleting the unnecessary files

•         Arranging the folders in order and deleting the unnecessary folders

•       Renaming the files and folders

•       Changing the storage location of files and folders

•       Creating backups of the files and folders as needed

Methods used for accessing the files

 

Security Management

There are many security threats to a computer.

1 Malicious Software (Malware)

                                ex - virus could harm the smooth functioning of a computer

2 Unauthorized access

                                deletion or destruction of data/information

Various kinds of techniques are used by the Operating System to Protect Computer.

• Anti-virus software
• Used password
• Keep file /folder in deferent places in computer
• Keep Backup (Use CD, DVD, flash drive, internet )

Network Management

·          OS support wired and wireless connectivity for hardware devices in the system such as computers, printers, scanners that exist in the network.

·         The OS helps in accessing one computer from a remote computer.

·         A computer network facilitates from simple text communication to a multimedia data communication.

Ex - Cloud Computing

2. Providing user friendly interface

·         We need an interface to interact with the computer.

·         An OS provides a user interface to input commands and instructions in a user friendly manner.

·         two types of user interfaces

1. Command Line Interface-CLI

2. Graphical User Interface-GUI

Command Line Interface (CLI)

-          Used in early days computer

-          ‘prompt’ used to keying commands using a keyboard.

-          In this correct syntax has to be used

-          Components in CLI are Command prompt, Curser, Command and Output

Graphical User Interface-GUI

-          present day computers are used

-          This  provides the ability to use the mouse or finger tips to navigate the commands

-          It has become much easier to interact with the computers

-          Components of GUI are  Windows     Icons               Menus             Pointer

and these components are abbreviated as WIMP

The utility programs in an Operating System

·         Backup Software - To copy files and take back up of hard drives

•    Disk scanner - To check the errors in hard drive

•    File/data compression - Compression of larger files into smaller files

•    Task Manager - to display information regarding the processes and programmes in a computer and the general status of the computer

•    System diagnosis tools - to monitor errors in hardware and software of a computer or network of computers and diagnosis of system errors.

•    Anti-Virus Software - Protecting the computer by identifying and eliminating malicious software

•    Clipboard - temporary storage of data/files for cut/copy and paste operations

•    Data synchronization software - to establish consistency among data from a source to a target data storage and vice versa

•    Screensavers - for blanking the screen or filling it with moving images or patterns when the computer is not in use.

•    System profilers - to provide detailed information about the software installed and hardware attached to the computer.

•    Network utilities - to analyze the computer's network connectivity, configure network settings, check data transfer or log events.

•        Disk Partitioning-  The process of dividing an individual drive into multiple logical drives is called disk partitioning. (C: drive D: drive)

-          partitioning is performed at the time

ü  when a hard disk is configured for the first time.

ü  when a new hard disk is to be added

ü  when an existing hard disk is replaced with a new hard disk.

-          Why do we need partitioning?

ü  When we need to save different items in different places.

Ex: Software in one drive and all other data in another drive

ü  When we need to have more than one Operating System in the same machine.

ü  To meet the requirement of the Operating System

*    When an already partitioned hard disk is partitioned again, all the data in that hard disk would be deleted. Therefore, it is necessary to a backup copy of the existing data before partitioning again.

*    In Linux environment all the partitions, multimedia drives, flash drives etc would be identified as individual folders (called Directories). Therefore it cannot be seen drives named C: D:

·         Disk Formatting - the process of preparing a data storage device such as a hard disk drive, solid-state drive, floppy disk or USB flash drive for storing data.

-          The USB Flash Drives come pre-formatted so that they can be put into use directly.

-          Can format hard disk drive, solid-state drive, floppy disk or USB flash drive whenever need arises

-          Usually a hard disk is partitioned and formatted before installing an OS for the first time. After that the need for partitioning or formatting could arise very rarely.        

-          It is necessary to keep back up copies of the data before formatting.

·         Defragmentation - Organizing the hard disk by rearranging clusters of small spaces together and creating a larger free space.

-          This increases the efficiency of the hard disk.

-          fragmentation Occur

ü  When the process where a single file is broken into different pieces and stored in different parts of the disk

ü  When the empty spaces that are created in the disk due to the deletion of files is used to save new files

ü  there is no need for ‘defragmentation utility’ in Linux based Operating Systems.

-          Linux OS makes sure that ample space is left between the saved files so that they can be saved at the same location as a single intact file even when the file expands due to editing.

-          Linux based OSs have the ability even to relocate the file in a new place if the file exceeds its allocated memory space.

Introduction to File Systems

·         Computer system is used files to store data and file consist of two components

-          file name

-          file extension (file extension are hidden to the user by the OS by default).

	File Type		File Extension
1	MS Word  2007/2010	A	.pdf
2	Ms Word 97-2003	B	.xlsx
3	LiberOffice Writer	C	.docx
4	Adobe Acrobat	D	.ppt
5	MS Excel 2007/2010	E	.odt
6	MS Excel 97-2003	F	.doc
7	MS Access 2007/2010	G	.pptx
8	MS Access 97 - 2003	H	.accdb
9	Ms Power point 2007/2010	I	.mdb
10	Ms Power Point 97-2003	J	.xls

                       

-          The OS maintains many information relevant to the file.

Type of file                  Size of the File             Saved Date and Time

-          A location is used in the storage space to save a file is called a drive.

-          Usually we create a folder in a drive and then store the file it in.

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