os introduction

Operating System

Operating System

• Is a program designed to run other programs on a computer. A computer’s operating system manage both software and hardware resources.

OS Conceptual view

Function of Operating Systems

User Interface

• User interface control how you enter data and instruction and how information is displayed on the screen.

User Interface

1. Command Line Interface (CLI)

User Interface

1. Command Line Interface (CLI)It involves the computer responding to

commands typed by the operator. This type of interface has the drawback that requires the operator to remember a range of different commands and is not ideal for novice users.

User Interface

2. Menu Driven Interface

User Interface

2. Menu Driven InterfaceUser do not need to memorize keywords such as copy, paste and syntax. On screen, menu driven interface provide menu as mean for entering command

Example: ATMs

User Interface

• Graphical User Interface

User Interface

• Graphical User InterfaceUser friendly. It interact with visual image such as button and icon and sometimes also referred to as WIMP because they use Windows, Icons, Menus and Pointers

Different Interfaces of OS

• Command Line Interface (DOS)– User have to

memorize all the syntax to issue command

– Take a long time to learn

• Graphic User Interface– User friendly – Easy to use and

doesn’t require the users to memorize all the syntax to issues command

Types of Operating System

• Real-Time Operating System (RTOS)– Is a multitasking operating system that aims

at executing real applications.– It must be able to process data as it comes

in, typically without buffering delays.


• Real-Time Operating System (RTOS)Example:High-Definition Television

receiver and display. It needs to read a digital signal, decode it and display it as the data comes in.


• Multi-user– Is an OS that allows multiple users to

access a computer system at the same time.


• Multi-userExample:

Unix server – where multiple remote users have access(such as via Secure shell) to the Unix shell prompt at the same time.


• Multi-tasking vs. single-tasking– A multi-tasking operating system allows

more than one program to be running at the same time

– A single-tasking system has only one running program

http://en.wikipedia.org/wiki/Multi-tasking


• Multi-tasking Types1. Pre-emptive

• the operating system slices the CPU time and dedicates one slot to each of the programs.

Example: Solaris, Linux, 32-bit versions of both Windows NT and Win9x


• Multi-tasking Types2. Co-operative

• Cooperative multitasking is achieved by relying on each process to give time to the other processes in a defined manner.

Example: AmigaOS, 16-bit versions of Microsoft Windows


• Distributed– manages a group of independent computers

and makes them appear to be a single computer.

– When computers in a group work in cooperation, they make a distributed system.


• TemplatedIn an o/s, distributed and cloud computing

context,templating refers to creating a single virtual machine image as a guest operating system

http://en.wikipedia.org/wiki/Glossary_of_operating_systems_terms


• Embedded– are designed to be used in

embedded computer systems. – They are designed to operate on small

machines like PDAs with less autonomy. – Example: ATMs, cellphones, printers,

thermostats, calculators

http://en.wikipedia.org/wiki/Embedded_system

• All user software needs to go through the operating system in order to use any of the hardware, whether it be as simple as a mouse or keyboard or as complex as an Internet component.

OS Components

Examples of Operating System

• Unix and Unix-like operating systems


• Unix and Unix-like operating systems– Unix-like systems run on a wide variety of

computer architectures. They are used heavily for servers in business, as well as workstations in academic and engineering environments.

http://en.wikipedia.org/wiki/Computer_architecture

http://en.wikipedia.org/wiki/Server_(computing)

http://en.wikipedia.org/wiki/Workstation


• BSD and its descendants


• BSD and its descendants-These operating systems are most commonly found on webservers

http://en.wikipedia.org/wiki/Webserver


• OS X– (formerly "Mac OS X") is a line of

open core graphical operating systems developed, marketed, and sold by Apple Inc.,

http://en.wikipedia.org/wiki/Open_core

http://en.wikipedia.org/wiki/Apple_Inc.


• OS X


• Linux and GNU


• Linux and GNU– is a Unix-like operating system that was

developed without any actual Unix code, unlike BSD and its variants. GNU/Linux can be used on a wide range of devices from supercomputers to wristwatches.


• Google Chromium OS– Chromium is an operating system based on

the Linux kernel and designed by Google.

http://en.wikipedia.org/wiki/Google

Example of Operating System

• Microsoft Windows– Microsoft Windows is a family of proprietary

operating systems designed by Microsoft Corporation and primarily targeted to Intel architecture based computers

http://en.wikipedia.org/wiki/Proprietary_software

http://en.wikipedia.org/wiki/Microsoft_Corporation


• Other– AmigaOS; OS/2 from IBM and Microsoft;

Mac OS, the non-Unix precursor to Apple's Mac OS X; BeOS; XTS-300; RISC OS; MorphOS; Haiku;BareMetal and FreeMint.

http://en.wikipedia.org/wiki/AmigaOS

http://en.wikipedia.org/wiki/OS/2

http://en.wikipedia.org/wiki/Mac_OS

http://en.wikipedia.org/wiki/BeOS

http://en.wikipedia.org/wiki/XTS-400

http://en.wikipedia.org/wiki/RISC_OS

http://en.wikipedia.org/wiki/MorphOS

http://en.wikipedia.org/wiki/Haiku_(operating_system)

http://en.wikipedia.org/wiki/BareMetal

http://en.wikipedia.org/wiki/FreeMint

OS Components

• The components of an operating system all exist in order to make the different parts of a computer work together

OS Components

• Kernel

OS Components

• Kernel- the kernel provides the most basic level of control over all of the computer's hardware devices. It manages memory access for programs in the RAM

http://en.wikipedia.org/wiki/RAM

OS Components

• Program execution– provides an interface between an

application program and the computer hardware

OS Components

• Interrupts– are central to operating systems, as they

provide an efficient way for the operating system to interact with and react to its environment.

OS Components

• Modes

OS Components

• Modes

Types: 1. Supervisor Mode- operating system's kernel

for low level tasks that need unrestricted access to hardware

OS Components

• Modes

Types: 2. Protected Mode

and can only use hardware by communicating with the kernel

OS Components

• Memory management– This ensures that a program does not

interfere with memory already in use by another program.

OS Components

• Virtual memory– memory managem

ent technique that is implemented using both hardware and software

– It maps memory addresses used by a program, called virtual addresses, into physical addresses in computer memory.

OS Components

• Multitasking– refers to the running of multiple independent

computer programs on the same computer; giving the appearance that it is performing the tasks at the same time.

OS Components

• Disk access and file systems– Access to data stored on disks is a central

feature of all operating systems.

OS Components

• Disk access and file systems– Access to data

stored on disks is a central feature of all operating systems.

OS Components

• Device drivers– is a specific type of computer software

developed to allow interaction with hardware devices.

OS Components

• Networking– This means that computers running

dissimilar operating systems can participate in a common network for sharing resources such as computing, files, printers, and scanners using either wired or wireless connections.

http://en.wikipedia.org/wiki/Computer_network

http://en.wikipedia.org/wiki/Remote_procedure_call

OS Components

• Security– The operating system must be capable of

distinguishing between requests which should be allowed to be processed, and others which should not be processed.

-- "privileged" and "non-privileged"

OS Statistics (2014)

Desktop Operating System Market Share

Common Types of OS

• Linux• Unix• Windows• Mac OS

Common Types of OS

• Linux is a free and open-source operating system developed by Linus Torvalds and friends and was first announced by Linus in a post he made August 25, 1991.

• The Linux kernel runs on numerous different platforms including the Intel and Alpha platform and is available under the GNU General Public License.

Common Types of OS

• Unix or UNIX (not an acronym) A term coined by Brian Kernighan– is an operating system that was developed

by some of the members of the MULTICS team at the Bell Laboratories starting in the late 1960's, many of who also helped create the C programming language.

Common Types of OS

• Mac OS is a series of graphical user interface-based operating systems developed by Apple Inc. for their Macintosh line of computer systems. The original operating system was first introduced in 1984 as being integral to the original Macintosh, and referred to as the "System".

Common Types of OS

• Microsoft Windows or Windows is a superfamily of graphical operating systems developed, marketed, and sold by Microsoft. It consists of several families of operating systems, each of which cater to a certain sector of the computing industry.

http://en.wikipedia.org/wiki/Operating_systemhttp://www.netmarketshare.com/operating-system-market-sharehttp://www.computerhope.com

os introduction

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