PREPARED BYADARSH BANG16H61A0401

OPERATING SYSTEMS

• An operating system (OS) is system software that manages computer hardware and software resources and provides common services for computer programs. All computer programs, excluding firmware, require an operating system to function.

• Time-sharing operating systems schedule tasks for efficient use of the system and may also include accounting software for cost allocation of processor time, mass storage, printing, and other resources.

Single- and multi-tasking

• A single-tasking system can only run one program at a time, while a multi-tasking operating system allows more than one program to be running in concurrency. This is achieved by time-sharing, dividing the available processor time between multiple processes that are each interrupted repeatedly in time slices by a task-scheduling subsystem of the operating system.

OPERATING SYSTEM

Single- and multi-user

• Single-user operating systems have no facilities to distinguish users, but may allowmultiple programs to run in tandem. A multi-user operating system extends the basicconcept of multi-tasking with facilities that identify processes and resources, such asdisk space, belonging to multiple users, and the system permits multiple users tointeract with the system at the same time.

Distributed

• A distributed operating system manages a group of distinct computers and makesthem appear to be a single computer. The development of networked computers thatcould be linked and communicate with each other gave rise to distributed computing.

Templated

In an OS, distributed and cloud computing context, templating refers to creating asingle virtual machine image as a guest operating system, then saving it as a tool formultiple running virtual machines.

Embedded

• Embedded operating systems are designed to be used in embedded computer systems.They are designed to operate on small machines like PDAs with less autonomy. They are able to operate with a limited number of resources.

Real-time

• A real-time operating system is an operating system that guarantees to process eventsor data by a specific moment in time. A real-time operating system may be single- or multi-tasking, but when multitasking, it uses specialized scheduling algorithms so that adeterministic nature of behaviour is achieved

Library

A library operating system is one in which the services that a typical operating system provides, such as networking, are provided in the form of libraries. These libraries are composed with the application and configuration code to construct unikernels.

Windows Linux IOS

We will be discussing briefly about the following 4 operating systems

WINDOWS

• There are so many operating systemsexits (i.e. Window, Linux, Unix etc.)but Windows is the most widely usedoperating system. Windows is the invention of Microsoft.

• Windows is a graphical environment which incorporates all the features of GUI.

• It lays a graphical user interface(GUI) shall around the DOS and extends DOS capabilities.

• It is easy to use and capable of multitasking i.e. running several application program simultaneously

• Graphic program (Windows) and character-based programs (DOS)can be run concurrently.

• It facilitates to switch between easily multiple program.

WINDOWS

• A computer environment like windows that uses little pictures and symbols is called graphical user interface.

• A user-interface acts as a link between computer and the user.

• A character user-interface uses text to help a user to give commandsto the application program

• You can use Control Panel for changing your screen colour installing& changing setting for hardware and software, setting up orchanging for a network.

• you can manage your desktop.

• The Windows Explorer graphically displays your entire computersystem in hierarchical tree structure.

IOS• Apples mobile operating system considered the foundation of the iPhone

• Originally designed for the iPhone but now supports iPod touch, iPad, and Apple TV

• It is updated just like Itunes for iPods

• As of Oct 2011 Apple contains over 500,000 iOS applications

IOS HISTORY

Ios (iphone o.s) is a mobile operating system developed by Apple.Inc started in 2007 with the first iphone 2G.

It extended to support other apple devices such as ipod,ipad etc..

It is programmed in C,C++,Objective-C.

Apple doesn’t license ios for installation on non- apple hardware.

LINUX• Linux is a generic term referring to Unix-like graphical user interface

(GUI) based computer operating systems.

• It is Multi-user, Multitasking, Multiprocessor

• Coexists with other Operating Systems

• Runs on multiple platforms

LINUX today• Linux has been used for many computing platforms

• PC, Supercomputer

• Commercial vendors moved in Linux itself to provide freely distributed

code. They make their money by compiling up various software and

gathering them in a distributable format

• About 29 million people use Linux worldwide

LINUX softwares

Red Hat Linux : • One of the original Linux distribution.• The commercial, nonfree version is Red Hat Enterprise Linux, which

is aimed at big companies using Linux servers and desktops in a big way

Debian GNU/Linux :

A free software distribution. Popular for use on servers

Gentoo Linux :

Gentoo is a specialty distribution meant for programmers