OPERATING SYSTEM

BY- Pratyush Ray

shovan karna

Amit kumar paricha

OPERATING SYSTEM

An operating system (OS) is software that manages computer hardware and software resources and provides common services for computer programs. The operating system is an essential component of the system software in a computer system. Application programs usually 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.

For hardware functions such as input and output and memory allocation, the operating system acts as an intermediary between programs and the computer hardware, although the application code is usually executed directly by the hardware and will frequently make a system call to an OS function or be interrupted by it. Operating systems can be found on almost any device that contains a computer—from cellular phones and video game consoles to supercomputers and web servers.

Examples of popular modern operating systems include Android, BSD, iOS, Linux, OS X, QNX, Microsoft Windows,[3] Windows Phone, and IBM z/OS. All these examples, except Windows, Windows Phone and z/OS, share roots in UNIX.

TYPES OF COMPUTER REAL TIME COMPUTER- A real-time operating system is a

multitasking operating system that aims at executing real-time applications. Real-time operating systems often use specialized scheduling algorithms so that they can achieve a deterministic nature of behaviour. The main objective of real-time operating systems is their quick and predictable response to events. They have an event-driven or time-sharing design and often aspects of both. An event-driven system switches between tasks based on their priorities or external events while time-sharing operating systems switch tasks based on clock interrupts. 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.

MULTI-USER:-  multi-user operating system allows multiple users to access a computer system at the same time. Time-sharing systems and Internet servers can be classified as multi-user systems as they enable multiple-user access to a computer through the sharing of time. Single-user operating systems have only one user but may allow multiple programs to run at the same time.

DISTRIBUTED:- A distributed operating system manages a group of independent computers and makes them appear to be a single computer. The development of networked computers that could be linked and communicate with each other gave rise to distributed computing. Distributed computations are carried out on more than one machine. When computers in a group work in cooperation, they make a distributed system.

TEMPLATED:- In an o/s, distributed and cloud computing context, templating refers to creating a single virtual machine image as a guest operating system, then saving it as a tool for multiple running virtual machines (Gagne, 2012, p. 716). The technique is used both in virtualization and cloud computing management, and is common in large server warehouses.

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. They are very compact and extremely efficient by design. Windows CE and MiniX 3 are some examples of

embedded operating systems.

History of operating systems

The earliest computers were mainframes that lacked any form of operating system. Each user had sole use of the machine for a scheduled period of time and would arrive at the computer with program and data, often on punched paper cards and magnetic or paper tape. The program would be loaded into the machine, and the machine would be set to work until the program completed or crashed. Programs could generally be debugged via a control panel using toggle switches and panel lights. It is said that Alan Turing was a master of this on the early Manchester Mark 1 machine, and he was already deriving the primitive conception of an operating system from the principles of the Universal Turing machine.

Symbolic languages, assemblers, and compilers were developed for programmers to translate symbolic program-code into machine code that previously would have been hand-encoded. Later machines came with libraries of support code on punched cards or magnetic tape, which would be linked to the user's program to assist in operations such as input and output. This was the genesis of the modern-day operating system. However, machines still ran a single job at a time. At Cambridge University in England the job queuewas at one time a washing line from which tapes were hung with different colored clothes-pegs to indicate job-priority. As machines became more powerful, the time to run programs diminished and the time to hand off the equipment to the next user became very large by comparison. Accounting for and paying for machine usage moved on from checking the wall clock to automatic logging by the computer. . Automated monitoring was needed not just for CPU usage but for counting pages printed, cards punched, cards read, disk storage used and for signaling when operator intervention was required by jobs such as changing magnetic tapes and paper forms. Security features were added to operating systems to record audit trails of which programs were accessing which files and to prevent access to a production payroll file by an engineering program, for example.

All these features were building up towards the repertoire of a fully capable operating system. Eventually the runtime libraries became an amalgamated program that was started before the first customer job and could read in the customer job, control its execution, record its usage, reassign hardware resources after the job ended, and immediately go on to process the next job. These resident background programs, capable of managing multistep processes, were often called monitors or monitor-programs before the term OS established itself.

An underlying program offering basic hardware-management, software-scheduling and resource-monitoring may seem a remote ancestor to the user-oriented OSes of thepersonal computing era. But there has been a shift in the meaning of OS. Just as early automobiles lacked speedometers, radios, and air-conditioners which later became standard, more and more optional software features became standard features in every OS package, although some applications such as data base management systems andspreadsheets remain optional and separately priced. This has led to the perception of an OS as a complete user-system with an integrated graphical user interface, utilities, some applications such as text editors and file managers, and configuration tools.

The true descendant of the early operating systems is what is now called the "kernel". In technical and development circles the old restricted sense of an OS persists because of the continued active development of embedded operating systems for all kinds of devices with a data-processing component, from hand-held gadgets up to industrial robots andreal-time control-systems, which do not run user applications at the front-end. An embedded OS in a device today is not so far removed as one might think from its ancestor of the 1950s.

The broader categories of systems and application software are discussed in the computer software article.

MAINFRAMESThe first operating system used for real work was GM-NAA I/O, produced in 1956 by General Motors' Research division[1] for its IBM 704.[2] Most other early operating systems for IBM mainframes were also produced by customers.[3]

Early operating systems were very diverse, with each vendor or customer producing one or more operating systems specific to their particular mainframe computer. Every operating system, even from the same vendor, could have radically different models of commands, operating procedures, and such facilities as debugging aids. Typically, each time the manufacturer brought out a new machine, there would be a new operating system, and most applications would have to be manually adjusted, recompiled, and retested.

RISE OF OS ON VIDEOGAMES

Since virtually all video game consoles and arcade cabinets designed and built after 1980 were true digital machines (unlike the analog Pong clones and derivatives), some of them carried a minimal form of BIOS or built-in game, such as the ColecoVision, the Sega Master System and the SNK Neo Geo.

Modern-day game consoles and videogames, starting with the PC-Engine, all have a minimal BIOS that also provides some interactive utilities such as memory card management, audio or video CD playback, copy protection and sometimes carry libraries for developers to use etc. Few of these cases, however, would qualify as a true operating system.

Long before that, Sony had released a kind of development kit called the Net Yaroze for its first PlayStation platform, which provided a series of programming and developing tools to be used with a normal PC and a specially modified "Black PlayStation"

that could be interfaced with a PC and download programs from it. These operations require in general a functional OS on both platforms involved.

In general, it can be said that videogame consoles and arcade coin operated machines used at most a built-in BIOS during the 1970s, 1980s and most of the 1990s, while from the PlayStation era and beyond they started getting more and more sophisticated, to the point of requiring a generic or custom-built OS for aiding in development and expandability.

Mobile os :- 1973–1993 Mobile phones use embedded systems to control operation.

1995 The first smartphone, the IBM Simon, has a touchscreen, email and PDA features.

1996 Palm Pilot 1000 personal digital assistant is introduced with the Palm OS mobile operating system.

1996 First Windows CE Handheld PC devices are introduced.

1999 Nokia S40 OS is officially introduced along with the Nokia 7110

PRESENT DAY ScENaRIOWith time technology has changed a lot and the operating system to run this has also advanced . The different types of operating system used in today world are-

OS USED IN COMPUTERS:- 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, rewritten in C, developed into a large, complex family of inter-related operating systems which have been influential in every modern operating system.

The Unix-like family is a diverse group of operating systems, with several major sub-categories including System V, BSD, and Linux. The name "UNIX" is a trademark of The Open Group which licenses it for use with any operating system that has been shown to conform to their definitions. "UNIX-like" is commonly used to refer to the large set of operating systems which resemble the original UNIX.

Four operating systems are certified by The Open Group (holder of the Unix trademark) as Unix. HP's HP-UX and IBM's AIX are both descendants of the original System V Unix and are designed to run only on their respective vendor's hardware. In contrast, Sun Microsystems's Solaris Operating System can run on multiple types of hardware, includingx86 and Sparc servers, and PCs. Apple's OS X, a replacement for Apple's earlier (non-Unix) Mac OS, is a hybrid kernel-based BSD variant derived from NeXTSTEP, Mach, and FreeBSD.

Unix interoperability was sought by establishing the POSIX standard. The POSIX standard can be applied to any operating system, although it was originally created for various Unix variants.

BSD and its descendants- A subgroup of the Unix family is the Berkeley Software Distribution family, which includes FreeBSD, NetBSD, and OpenBSD. These operating systems are most commonly found on webservers, although they can also function as a personal computer OS. The Internet owes much of its existence to BSD, as many of the protocols now commonly used by computers to connect, send and receive data over a network were widely implemented and refined in BSD. The World Wide Web was also first demonstrated on a number of computers running an OS based on BSD called NextStep.

OS X:- OS X (formerly "Mac OS X") is a line of open core graphical operating systems developed, marketed, and sold by Apple Inc., the latest of which is pre-loaded on all currently shipping Macintosh computers. OS X is the successor to the original Mac OS, which had been Apple's primary operating system since 1984. Unlike its predecessor, OS X is a UNIX operating system built on technology that had been developed at NeXT through the second half of the 1980s and up until Apple purchased the company in early 1997. The operating system was first released in 1999 as Mac OS X Server 1.0, with a desktop-oriented version (Mac OS X v10.0 "Cheetah") following in March 2001. Since then, six more distinct "client" and "server" editions of OS X have been released, until the two were merged in OS X 10.7 "Lion". The most recent version is OS X 10.9 "Mavericks", which was announced on June 10, 2013, and released on October 22, 2013. Releases of OS X v10.0 through v10.8 are named after big cats. Starting with v10.9, "Mavericks", OS X versions are named after inspirational places in California.

Linux and GNU:- The GNU project is a mass collaboration of programmers who seek to create a completely free and open operating system that was similar to Unix but with completely original code. It was started in 1983 by Richard Stallman, and is responsible for many of the parts of most Linux variants. Thousands of pieces of software for virtually every operating system are licensed under the GNU General Public License. Meanwhile, the Linux kernel began as a side project of Linus Torvalds, a university student from Finland. In 1991, Torvalds began work on it, and posted information about his project on a newsgroup for computer students and programmers. He received a wave of support and volunteers who ended up creating a full-fledged kernel. Programmers from GNU took notice, and members of both projects worked to integrate the finished GNU parts with the Linux kernel in order to create a full-fledged operating system.

The Linux kernel is used in some popular distributions, such as Red Hat, Debian, Ubuntu, Linux Mint and Google's Android.

Google Chromium OS:- Chromium is an operating system based on the Linux kernel and designed by Google. Since Chromium OS targets computer users who spend most of their time on the Internet, it is mainly a web browser with limited ability to run local applications, though it has a built-in file manager and media player. Instead, it relies on Internet applications (or Web apps) used in the web browser to accomplish tasks such as word processing.[14] Chromium OS differs from Chrome OS in that Chromium is open-source and used primarily by developers whereas Chrome OS is the operating system shipped out in Chromebooks.

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 8.1 for workstations and Windows Server 2012 R2 for servers. Windows 7 recently overtook Windows XP as most used OS.

Microsoft Windows originated in 1985 as an operating environment running on top of MS-DOS, which was the standard operating system shipped on most Intel architecture personal computers at the time. In 1995, Windows 95 was released which only used MS-DOS as a bootstrap. For backwards compatibility, Win9x could run real-mode MS-DOS and 16 bits Windows 3.x[24] drivers. Windows ME, released in 2000, was the last version in the Win9x family. Later versions have all been based on the Windows NTkernel. Current client versions of Windows run on IA-32, x86-64 and 32-bit ARM microprocessors.[25] In addition Itanium is still supported in older server version Windows Server 2008 R2. In the past, Windows NT supported additional architectures.

Server editions of Windows are widely used. In recent years, Microsoft has expended significant capital in an effort to promote the use of Windows as a server operating system. However, Windows' usage on servers is not as widespread as on personal computers, as Windows competes against Linux and BSD for server market share.

AndroidAndroid (based on the Linux Kernel) is from Google Inc..[5] It has the largest installed base worldwide on smartphones. Most of Android is free and open source,[6] but a large amount of software on Android devices (such as Play Store, Google Search, Google Play Services, Google Music, and so on) are proprietary and licensed.[7]

 Android's releases prior to 2.0 (1.0, 1.5, 1.6) were used exclusively on mobile phones. Android 2.x releases were mostly used for mobile phones but also some tablets. Android 3.0 was a tablet-oriented release and does not officially run on mobile phones. The current Android version is 4.4 Android's releases are nicknamed after sweets or dessert items like Cupcake (1.5), Donut (1.6), Eclair (2.0), Frozen Yogurt ("Froyo") (2.2), Ginger Bread (2.3), Honeycomb (3.0), Ice Cream Sandwich (4.0), Jelly Bean (4.1), (4.2), (4.3) Kit Kat (4.4), and Lollipop (5.0). Most major mobile service providers carry an Android device. Since HTC Dream was introduced, there has been an explosion in the number of devices that carry Android OS. From second quarter of 2009 to the second quarter of 2010, Android's worldwide market share rose 850% from 1.8% to 17.2%. On November 15, 2011, Android reached 52.5% of the global smartphone market share.[8] On September 2014 Android's global market share rose to 85%.[9]

OSiOS is from Apple Inc.. It has second largest installed base worldwide on smartphones behind Android. It is closed source and proprietary and built on open source Darwin core OS. The Apple iPhone, iPod Touch, iPad and second-generation Apple TV all use an operating system called iOS, which is derived from Mac OS X. Native third party applications were not officially supported until the release of iOS 2.0 on July 11, 2008. Before this, "jailbreaking" allowed third party applications to be installed, and this method is still available. Currently all iOS devices are developed by Apple and manufactured by Foxconn or another of Apple's partners. As of September 2014, iOS global market share was 11%.[9]

Windows PhoneWindows Phone is from Microsoft. It is closed source and proprietary. It has third largest installed base on smartphones behind Android and iOS. On February 15, 2010, Microsoft unveiled its next-generation mobile OS, Windows Phone. The new mobile OS includes a completely new over-hauled UI inspired by Microsoft's "Metro Design Language". It includes full integration of Microsoft services such as OneDrive and Office, Xbox Music, Xbox Video, Xbox Live games and Bing, but also integrates with many other non-Microsoft services such as Facebook and Google accounts. Windows Phone devices are made primarily by Nokia, along with HTC, Samsung. As of September 2014, Windows Phone market share was 3%.[9]

BlackberryBlackBerry 10 (based on the QNX OS) is from BlackBerry. As a smart phone OS, it is closed source and proprietary. It is used mostly by Government employees. BlackBerry 10 is the next generation platform for BlackBerry smartphones and tablets. All phones and tablets are manufactured by Blackberry itself. Once one of the dominant platforms in the world, it's global market share has been reduced to less than 1% in late 2014.

Firefox OS

Firefox OS[10] is from Mozilla. It is open source and uses Mozilla Public License. According to Ars Technica, "Mozilla says that B2G is motivated by a desire to demonstrate that the standards-based open Web has the potential to be a competitive alternative to the existing single-vendor application development stacks offered by the dominant mobile operating systems."

Sailfish OSSailfish OS is from Jolla. It is partly open source and adopts GPL (core and middleware), however the user interface is closed source. After Nokia failed in 2011 with the MeeGoproject most of the MeeGo team have left Nokia, and established Jolla as a company to use MeeGo and MER business opportunities. In 2012 Linux Sailfish OS based on MeeGo and using MER core distribution has been launched for public use. The first device, Jolla (mobile phone) was unveiled on 20 May 2013.