OPERATING SYSTEMS

What is operating system?? An operating system (OS) is a

collection of software that manages computer hardware resources and provides common services for computer programs.

The operating system is a vital component of the system software in a computer system.

Application programs usually require an operating system to function.

History Early computers were built to

perform a series of single tasks, like a calculator. Operating systems did not exist in their modern and more complex forms until the early 1960s.

In the 1940s, the earliest electronic digital systems had no operating systems. Electronic systems of this time were programmed on rows of mechanical switches or by jumper wires on plug boards.

In the early 1950s, a computer could execute only one program at a time. Each user had sole use of the computer for a limited period of time and would arrive at a scheduled time with program and data on punched paper cards and/or punched tape.

Later machines came with libraries of programs, which would be linked to a user's program to assist in operations such as input and output and generating computer code from human-readable symbolic code.

Mainframes Mainframe

computers  are computers used primarily by corporate and governmental organizations for critical applications, bulk data processing such as census, industry and consumer statistics, enterprise resource planning, and transaction processing.

The term originally referred to the large cabinets that housed the central processing unit and main memory of early computers.

Later, the term was used to distinguish high-end commercial machines from less powerful units. Most large-scale computer system architectures were established in the 1960s, but continue to evolve.

Microcomputers

The first microcomputers did not have the capacity or need for the elaborate operating systems that had been developed for mainframes and minis; minimalistic operating systems were developed, often loaded from ROM and known as monitors.

One notable early disk operating system was CP/M, which was supported on many early microcomputers and was closely imitated by Microsoft's MS-DOS, which became wildly popular as the operating system chosen for the IBM PC.

The introduction of the Intel 80386 CPU chip with 32bit architecture and paging capabilities, provided personal computers with the ability to run multitasking operating systems like those of earlier minicomputers and mainframes.

 Steve Jobs, a co-founder of Apple Inc., started NeXT Computer Inc., which developed the NEXTSTEP operating system. NEXTSTEP would later be acquired by Apple Inc. and used, along with code from FreeBSD as the core of Mac OS X.

The enormous investment in software for these systems made since 1960s caused most of the original computer manufacturers to continue to develop compatible operating systems along with the hardware. The notable supported mainframe operating systems include:

Burroughs MCP – B5000, 1961 to Unisys Clearpath/MCP, present.

IBM OS/360 – IBM System/360, 1966 to IBM z/OS, present.

IBM CP-67 – IBM System/360, 1967 to IBM z/VM, present.

UNIVAC EXEC 8 – UNIVAC 1108, 1967, to OS 2200 Unisys Clearpath Dorado, present.

Examples of operating systems UNIX and UNIX-like operating

systems Unix was originally written in

assembly language. Ken Thompson wrote B, mainly based on BCPL, based on his experience in the MULTICS project. B was replaced by C, and Unix, rewriten in C, developed into a large, complex family of inter-related operating systems which have been influential in every modern 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, with an estimated 88.9 percent total usage share on Web connected computers. The newest version is Windows 8 for workstations and Windows Server 2012 for servers. Windows 7 recently overtook Windows XP as most used OS

OS X

OS X , previously Mac OS X, is a series of Unix-based graphical interface operating systems developed, marketed, and sold by Apple Inc. It is designed to run exclusively on Mac computers, having been pre-loaded on all Macs since 2002. It was the successor to Mac OS 9, released in 1999, the final release of the "classic" Mac OS, which had been Apple's primary operating system since 1984. 

Linux and GNU

Linux (or GNU/Linux) is a Unix-like operating system that was developed without any actual Unix code, unlike BSD and its variants.

Linux can be used on a wide range of devices from supercomputers to wristwatches.

The Linux kernel is released under an open source license, so anyone can read and modify its code. It has been modified to run on a large variety of electronics.

Although estimates suggest that Linux is used on 1.82% of all personal computers, it has been widely adopted for use in servers and embedded systems[

Android(operating systems) Android is a Linux-based operating

system designed primarily for touchscreen mobile devices such as smartphones and tablet computers. Initially developed by Android, Inc., whom Google financially backed and later purchased in 2005.

Android is open source and Google releases the code under the Apache License. This open source code and permissive licensing allows the software to be freely modified and distributed by device manufacturers, wireless carriers and enthusiast developers. Additionally, Android has a large community of developers writing applications that extend the functionality of devices, written primarily in a customized version of the Java programming language.

Apple iOS

iOS (previously iPhone OS) is a mobile operating system developed and distributed by Apple Inc. Originally released in 2007 for the iPhone and iPod Touch, it has been extended to support other Apple devices such as the iPad and Apple TV.

The user interface of iOS is based on the concept of direct manipulation, using multi-touch gestures. Interface control elements consist of sliders, switches, and buttons. Interaction with the OS includes gestures such as swipe, tap, pinch, and reverse pinch, all of which have specific definitions within the context of the iOS operating system and its multi-touch interface.

Internal accelerometers are used by some applications to respond to shaking the deviceor rotating it in three dimensions 

The future of operating systems. Operating systems have evolved through

the past years in a rapid manner. As the most important component in

computers, changes in the operating systems have great consequences for users of computers.

With the past changes in operating systems like the giant rise from command-line interface to the current graphical user interface, many common tasks became easier for the computer users.

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Done By MAHARAJA MUKHERJEE IX-A