Introduction to Operating System

1.  Operating System - Definition
 User Interface
 Functions Of Operating System
Operating System
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2. OPERATING SYSTEM
 Operating system is an interface or link between the
software and hardware.
 The main job of operating system is to control and monitor
the functions of the system.
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3. Computer Hardware
User communication with computer
Application software
Editors and compilers
Operating systems
Assemblers,Utilities,Tools
User friendly packages
OPERATING SYSTEM AND SOFTWARE LAYERS
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4. OPERATING SYSTEM AND SOFTWARE LAYERS
 Assembler – to convert assembly instruction to machine code
 Compiler and interpreter - To translate high level language
instructions to machine code.
 Utilities – To provide sort/ merge, spread sheet, text processing, and
database facilities.
 Debugging tools: To facilitate removal of errors in the source program.
 Editors : To enter the source program and data
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5. TYPE OF USER INTERFACE
 User interface is used to interact with the computer to perform various
tasks.
 User gives commands to computer and enter the data into computer.
 The input devices are commonly used for giving commands to
computer
 There are three types of user interface
 Command Line Interface (CLI)
 Menu Driven Interface(MDI)
 Graphical User Interface(GUI)
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6. Command Line Interface (CLI)
 CLI requires the user to type commands in the command prompt to
perform operation
 It contains text only.
 Users must to know the syntax and keywords of the commands.
 Eg: DOS (Disk Operating System)
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7. Menu Driven Interface (MDI)
 One can select an option by using the arrow keys or click the desired
option with the mouse
 Users need not to know the syntax and keywords of the commands.
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8. Graphical User Interface
 The computer resources are represented by small pictures called
icons.
 User can initiate many actions by selecting and clicking on icons
displayed on the screen.
 GUI also provides menus, buttons and other graphical object to the
user to perform different task.
 Interaction with computer is made easier with GUI.
 Eg. Windows, Linux, Solaris
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9. Functions of Operating System
 Booting the computer
 Resource Management
 Process Management
 Memory Management
 I/O System Management
 File Manager
 Communication sService
 Security Services
 Hardware Services
 Extended Machine
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10. Functions of Operating System (Cont.)
Booting the computer
 The process of starting or restarting the computer is known as
booting.
 Cold boot- is a process of turning ON a computer that has been
turned OFF.
 Warm boot- is the process to restart the computer using operating
system.
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11. Resource Management
 The resource manager has to manage all the resources those are
attached to the computer.
 It handles system resource such as computer’s memory and sharing
the Central Processing Unit (CPU) time by various applications or
peripheral device.
Functions of Operating System (Cont.)
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12. Functions of Operating System (Cont.)
Process Management:
 A process is a program in execution.
 OS responsibilities in process management
• Process Creation and deletion
• Process suspension and resumption
• Process Synchronization and Inter-process
Communication
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13. Memory Management:
 OS responsibility for memory management
• Allocate and de-allocate memory spaces as requested
• Keep track of which parts of memory are currently being
used and by whom
• Efficient utilization when the memory resource is heavily
competed.
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Functions of Operating System (Cont.)

14. Functions of Operating System (Cont.)
I/O system Management:
 File Manager: the file management system allows the user to
perform the task such as creating files and directories, renaming
files, copying and moving files and delete files.
 Communication Service: the OS establish an internet connection
for surfing the web or sending e-mails. OS manage the
communication protocols and the network communication.
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15.  Security Service: OS has built-in tools to protect against security
threats such as virus. To control the access to the computer by
setting up password. Without password no one can not access the
files and application in computer
 Hardware Service : OS manages all the hardware and peripheral
device of computer. Eg: When saving a file to USB flash drive, the
OS check the space on the drive to store the file.
 Extended Service: It provide us sharing of files between multiple
users, provides the graphical environment and provide various
languages for communications.
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Functions of Operating System (Cont.)