This document provides an introduction to computer operating systems. It discusses key topics like the functions of an operating system, examples of common operating systems like Linux and Windows, and the basic tasks of an operating system like memory management, file management, and process management. The document also covers different types of operating systems like batch, time-sharing, single-user and multi-user systems, and components of an operating system like the kernel, microkernel, and user interface.

1. INTRODUCTION TO COMPUTER
SYSTEM
CSC 2313
LECTURE 2
Department of Maths and Computer-Science
Faculty of Natural andApplied Science
BY
UMAR DANJUMA MAIWADA

2. OBJECTIVES
 Learn the fundamental concept of operating system.
 Understand the functions of operating system.
 Study the types of operating system
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3. INTRODUCTION
 Operating system and windows.
 Operating system manages the computer hardware
and software resources and provides common services
for computer programs.
 Windows is a rectangular area on a computer screen
containing some kind of user interface, displaying
output.
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4. OPERATING SYSTEM
 It is a program that serves as an interface between the user and
the computer system which include both the hardware and
software resources.
 It support computer basic functions scheduling task and
controlling peripherals.
 Operating system are system of programs that manages
resources provide user-interface and run application
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6. OS BASICTASKS
 Scheduling task
 Controlling peripherals e.g disk drives,
printers
 File management
 Memory management
 Process management
 Handling input and output
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7. SOME OS
Linux Operating System,
 Windows Operating System,
 Ubuntu
UNIX
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8. FUNCTIONS OF OS
 Memory Management
 Processor Management
 Device Management
 File Management
 Security
 Control over system performance
 Job accounting
 Error detecting aids
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9. MEMORY MANAGEMENT
 When computer is turned on, the operating system is loaded
into the main memory (RAM).
 The operating system manages the remaining memory and
shares it between itself and the process that have been started.
 This allocation is based on the memory management scheme
adopted by the operating system.
 An Operating System does the following activities for memory
management:
 Keeps tracks of primary memory, i.e., what part of it are in use by
whom, what part are not in use.
 Allocates the memory when a process requests it to do so.
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10. FILE MANAGEMENT
 A disk stores data and information; it also has no inherent
mechanisms for organizing data or information into the file.
 The file management system maintains the directory structure
and stores directory, file information such as the data and time
at which files and directions were last modified along with the
details of ownership and access rights.
 An Operating System does the following activities for file
management:
 Keeps track of information, location, uses, status etc.The collective
facilities are often known as file system.
 Allocates the resources.
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11. PROCESSOR MANAGEMENT
 In multiprogramming environment, the OS decides which
process gets the processor when and for how much time.
 .An Operating System does the following activities for
processor management:
 Keeps tracks of processor and status of process.The program
responsible for this task is known as traffic controller.
 Allocates the processor (CPU) to a process.
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12. PROCESS MANAGEMENT
 Supports processing functions such as multitasking
 A process is the unit of work in a system.
 Running a program
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13. DEVICE MANAGEMENT
 Uses programs called device drivers to communicate with other
devices example monitor.
 An Operating System manages device communication via their
respective drivers.
 Keeps tracks of all devices.

14. I/O CONTROLLER
 Decides which process gets the device when and for how much
time.
 Allocates the device in the most efficient way.
 De-allocates devices.
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15. SCHEDULING
 Controls the order and time which programs and processors
are run.
 Placed in queue based on level of priority and eventually
executed
 Actual selection of processes that will be executed at any given
time

16. SECURITY
 The O/S system can act to protect the system from internal
and external intrusions.
 , the O/S provides the security that controls file access
permissions. Provisions of password to keep out unauthorized
users.
 Protect OS from users
 Protect users from other users
 Prevent unauthorized entry to system
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17. Network and Communication Services
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 TCP-IP protocol suite
 Locate and connect to other computers
 Access files, I/O devices, and programs from remote systems
 Support distributed processing
 Network Applications
 Email, remote login,Web services, streaming multimedia, voice
over IP telephony,VPN

18. System Administration Support
 Adding and deleting users
 Modifying user privileges
 System security
 Files systems management
 Network administration
 Backups
 Software installations and upgrades
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19. TYPES OF OPERATING SYSTEM
 Batch Operating System
 The users of a batch operating system do not interact with the
computer directly.
 Each user prepares his job on an off-line device and submits it to the
computer operator.
 To speed up processing, jobs with similar needs are batched together
and run as a group.
 Problems
 Lack of interaction between the user and the job.
 CPU is often idle, because the speed of the mechanical I/O devices is
slower than the CPU.
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o Time-sharing Operating Systems
Time-sharing is a technique which enables many people,
located at various terminals, to use a particular computer
system at the same time.
It is called multitasking.
Processor's time which is shared among multiple users
simultaneously is termed as time-sharing.
Advantages
Provides the advantage of quick response.
Avoids duplication of software.
Reduces CPU idle time.

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Single Job Processing: Only one program is loaded into
memory and executed. Rather than running
One program multiple times to process one transaction each
time, it will run only once for many transactions.
Concurrent Operations: it is the process of executing
multiple task at the same time.
Where we can find concurrent events e.g multiple applications,
multiple process.

22. SHARING THE CPU DURING I/O BREAKS
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23. USER INTERFACE AND
COMMAND EXECUTION SERVICES
 Types of user interfaces
 CLI - Command Line Interface
 GUI - Graphical User Interface
 Menu environment
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24. KERNEL
 It is a computer program that is the core of a computers OS
with complete control over everything in the system.
 A kernel connects the application software to the hardware of a
computer.
• Application
• Kernel
 CPU MEMORY DEVICE
 We have two types of kernel

25. MICRO KERNEL
It is the means of partitioning the instructions into many
kernels.
Features of micro kernel
security services
File system
Device drivers
Benefit of micro kernel
Flexibility- new features
Reliability
portability 25

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Monolithic Kernel
Its among the types of kernel whereby all instructions are stored in a
single kernel. Its disadvantage s are security and size.
It is alone supervisor mode.

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Single user, single tasking
Single user, multitasking
Multi-user, multitasking
Distributed systems
Processing power distributed among computers in a cluster or network
Network servers
Real-time systems
Embedded systems
Bootstrapping loading software into computer memory. Self
starting process
Execution begins with bootstrap loader (mini-loader, IPL) stored in
ROM
Looks for OS program in a fixed location
Loads OS into RAM
Transfers control to starting location of OS
Loader program in OS used to load and execute user programs
Cold vsWarm boot (does not retest the system).

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30. REFERENCES
1. Operating system by william stallings
2. OPERATING SYSTEM CONCEPTS by ABRAHAM
SILBERSCHATZ,Yale University, PETER BAER GALVIN, Corporate
Technologies, GREG GAGNE,Westminster College
3. Operating system concepts by Silberschatz Galvin Gagne.
4. Wikipedia.com
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31. QUESTIONS???
THANK YOU FOR YOUR ATTENTION
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