INDEXWhat is an operating system? ...................................................................................................................... 2

History of Operating Systems ....................................................................................................................... 3

Functions of Operating Systems .................................................................................................................. 3

Tasks of Operating Systems .......................................................................................................................... 5

1.Process Management ....................................................................................................................... 5

2.Memory Management ...................................................................................................................... 5

3.Device Management ......................................................................................................................... 5

4.Application interface ......................................................................................................................... 5

Services of Operating Systems ..................................................................................................................... 5

Components of an operating system ........................................................................................................... 7

Kernel ................................................................................................................................................... 7

Types of operating system ........................................................................................................................... 9

Batch operating system ........................................................................................................................ 9

Time-sharing operating systems .......................................................................................................... 9

Multiuser Operating System ................................................................................................................ 9

Multitasking Operating System ............................................................................................................ 9

Multiprocessing Operating System ...................................................................................................... 9

Multiprogramming Operating System ................................................................................................ 10

Multithreading Operating System ...................................................................................................... 10

Network Operating System ................................................................................................................ 10

Real-Time operating System .............................................................................................................. 10

Examples Computer of Operating Systems ................................................................................................ 11

Examples of Mobile Operating Systems ..................................................................................................... 13

Examples of Server Operating System ....................................................................................................... 15

Bibliography ............................................................................................................................................... 15

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What is an operating system?

An operating system (O.S.) is the system software, on the hard drive, thatcommunicates computer hardware and allows other programs to run. It manages all computerprograms excluding the firmware, which does not require an operating system to function. It is amaster control that automatically runs first when a computer is switched on, and remains in thebackground until the computer is turned off. It commonly comes preinstalled (on the boot sectionof the computer's main hard disk) and is usually the most complex and largest program to be usedby the computer. A computer user is typically more affected by the capabilities and whims of theO.S. than by those of the hardware. Common desktop operating systems include Windows O.S. X,and Linux.

The application programs make use of the operating system by making requests for servicesthrough a defined application program interface (API). In addition, users can interact directly withthe operating system through a user interface such as a command line or a graphical user interface(GUI).

When computers were first introduced, the user interacted with them using a commandline interface, which required commands. Today, almost every computer is using a Graphical UserInterface (GUI) operating system that is much easier to use and operate.

An embedded operating system is specialized for use in the computers built into largersystems, such as cars, traffic lights, digital televisions, ATMs, airplane controls, point of sale (POS)terminals, digital cameras, GPS navigation systems, elevators, digital media receivers and smartmeters.

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History of Operating Systems

Operating systems have evolved through several distinct phases or generations whichcorrespond roughly to the decades:

The 1940's - First Generations

The earliest electronic digital computers had no operating systems. Machines of the timewere so primitive that programs were often entered one bit at time on rows of mechanical switches(plug boards). Programming languages were unknown (not even assembly languages). Operatingsystems were unheard of.

The 1950's - Second Generation

By the early 1950's, the routine had improved somewhat with the introduction of punchcards. The General Motors Research Laboratories implemented the first operating systems in early1950's for their IBM 701. The system of the 50's generally ran one job at a time. These were calledsingle-stream batch processing systems because programs and data were submitted in groups orbatches.

The 1960's - Third Generation

The systems of the 1960's were also batch processing systems, but they were able to takebetter advantage of the computer's resources by running several jobs at once.

Another major feature in third-generation operating system was the technique calledspooling (simultaneous peripheral operations on line). In spooling, a high-speed device like a diskinterposed between a running program and a low-speed device involved with the program ininput/output. Instead of writing directly to a printer, for example, outputs are written to the disk.

Another feature present in this generation was time-sharing technique, a variant ofmultiprogramming technique, in which each user has an on-line (i.e., directly connected) terminal.Because the user is present and interacting with the computer, the computer system must respondquickly to user requests, otherwise user productivity could suffer. Timesharing systems weredeveloped to multi program large number of simultaneous interactive users.

Fourth Generation

With the development of LSI (Large Scale Integration) circuits, chips, operating systementered in the system entered in the personal computer and the workstation age. Microprocessortechnology evolved to the point that it became possible to build desktop computers as powerful asthe mainframes of the 1970s. Two operating systems have dominated the personal computer scene:MS-DOS, written by Microsoft, Inc. for the IBM PC and other machines using the Intel 8088 CPU

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and its successors, and UNIX, which is dominant on the large personal computers using theMotorola 6899 CPU family.

Functions of Operating Systems

Booting

Booting is a process of starting the computer operating system starts the computer to work.It checks the computer and makes it ready to work.

Memory Management

It is also an important function of operating system. The memory cannot be managedwithout operating system. Different programs and data execute in memory at one time. If there isno operating system, the programs may mix with each other. The system will not work properly.

Loading and Execution

A program is loaded in the memory before it can be executed. Operating system providesthe facility to load programs in memory easily and then execute it.

Data security

Data is an important part of computer system. The operating system protects the datastored on the computer from illegal use, modification or deletion.

Disk Management

Operating system manages the disk space. It manages the stored files and folders in aproper way.

Process Management

As CPU can perform one task at one time, if there are many tasks, operating system decideswhich task should get the CPU.

Device Controlling

Operating system controls all devices attached to computer. The hardware devices arecontrolled with the help of small software called device drivers.

Printing controlling

Operating system also controls printing function. If a user issues two print commands at atime, it does not mix data of these files and prints them separately.

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Providing interface

It is used in order that user interface acts with a computer mutually. User interface controls how you input data and instruction and how information is displayed on screen. The operating system offers two types of the interface to the user:

- Graphical-line interface: It interacts with of visual environment to communicate with the computer. It uses windows, icons, menus and other graphical objects to issues commands.

- Command-line interface: it provides an interface to communicate with the computer by typing commands.

Tasks of Operating Systems

1. Process Management

A process is an executing program. It has its code, data, a certain set of resources allowed toit, and one or more flows of execution through the code. The OS manages the allocation ofresources to these processes, and also provides system calls to manage these processes.

2. Memory Management

Memory must be shared between the O.S. and an application program. The O.S. mustmanage the allocation of memory to processes and control the memory management hardwarethat determines which memory locations a process may access.

3. Device Management

Information is sent through a computer’s input and output devices. Processes access thesedevices using the system call interface. The O.S. tries to manage said devices in a manner thatmakes them efficiently shared among all processes requiring them. A system call is a programminginterface to the services provided by the O.S., typically written in C/C++.

4. Application interface

Application program interface (API) is a set of routines, protocols, and tools for buildingsoftware applications. An API specifies how software components should interact and APIs areused when programming graphical user interface (GUI) components. APIs allow programmerseasier entry into another company's program or service. A good API makes it easier to develop aprogram by providing all the building blocks. A programmer then puts the blocks together.

5. The user interface (UI)

It is the space where interactions between humans and machines occur. The goal of thisinteraction is to allow effective operation and control of the machine from the human end, whilstthe machine simultaneously feeds back information that aids the operators' decision-makingprocess.

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Services of Operating Systems

An operating system provides services to both the users and the programs. It provides anenvironment to execute for programs and the services to execute the programs in a convenientmanner for users. The most important services of operating systems are:

Program execution

The purpose of computer systems is to allow the user to execute programs. So, the operating systemprovides an environment where the user can conveniently run programs. The main activities ofprogram execution are:

Loads a program into memory.

Executes the program.

Handles program's execution.

Provides a mechanism for process synchronization.

Provides a mechanism for process communication.

Provides a mechanism for deadlock handling.

I/O Operation

The operating systems hide the details of underlying hardware for the I/O. All the user sees is thatthe I/O has been performed without any details. So the operating systems by providing I/O make itconvenient for the users to run programs. An Operating System manages the communicationbetween user and device drivers.

I/O operation means read or write operation with any file or any specific I/O device. Operating system provides the access to the required I/O device when required.

File system manipulation

The operating system is in charge of providing the user or the program with the files they need.Computers stored the files in the secondary storage, so the O.S. needs to communicate with thismemory and take the files needed. The major activities of an operating system are:

Program needs to read a file or write a file. The operating system gives the permission to the program for operation on file. Permission varies from read-only, read-write and denied. Operating System provides an interface to the user to create/delete files. Operating System provides an interface to the user to create/delete directories. Operating System provides an interface to create the backup of file system.

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Communication

The operating system manages communications between all the processes. Multipleprocesses communicate with one another through communication lines in the network. The O.S.handles routing and connection strategies. The O.S. needs to manage:

Two processes often require data to be transferred between them.

Both the processes can be on one computer or on different computers, but are connectedthrough a computer network.

Communication may be implemented by two methods, either by Shared Memory or byMessage Passing.

Error handling

An error may occur in CPU, in I/O devices or in the memory hardware, anytime. To avoidsuch a situation, the operating system needs to:

The O.S. constantly checks for possible errors. The O.S. takes an appropriate action to ensure correct and consistent computing.

Protection

Protection refers to a mechanism or a way to control the access of programs, processes, or users tothe resources defined by a computer system. The various processes must be protected from eachother's activities. The major activities of an operating system are:

The O.S. ensures that all access to system resources is controlled.

The O.S. ensures that external I/O devices are protected from invalid access attempts.

The O.S. provides authentication features for each user by means of passwords.

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Components of an operating system

The components of an operating system all exist in order to make the different parts of acomputer work together. All user needs to go through the operating system in order to use any ofthe hardware.

Kernel

The kernel is the central part of anoperating system. It loads first, and it remains inmain memory. As the center of the operatingsystem, it is important for the kernel to be assmall as possible while still providing all theessential services required by other parts of theoperating system and applications. The kernelcode is usually loaded into a protected area ofmemory to prevent it from being overwritten by.The kernel need to be small, efficient and loadedinto a protected area in the memory; so as not tobe overwritten. The kernel is responsible of:

Loading or unloading applications from memory Process management Memory management File management Data security

There are five types of kernels:

Monolithic Kernels: All operating system services run along the main kernel thread in amonolithic kernel, which also resides in the same memory area, thereby providing powerful andrich hardware access.

Microkernels: Define a simple abstraction over hardware that use primitives or systemcalls to implement minimum O.S. services such as multitasking, memory management and interprocess communication.

Hybrid Kernels: they run a few services in the kernel space to reduce the performanceoverhead of traditional microkernels where the kernel code is still run as a server in the user space.

Nano Kernels: simplify the memory requirement by delegating services, including thebasic ones like interrupt controllers or timers to device drivers.

Exo Kernels: allocate physical hardware resources such as processor time and disk block toother programs, which can link to library operating systems that use the kernel to simulateoperating system abstractions.

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Device Drivers

A device driver is a group of files that enable one or more hardware devices to communicatewith the computer's operating system. Every piece of hardware that makes up the computer or areconnected to it, will have a device driver. A device driver essentially converts the more generalinput/output instructions of the operating system to messages that the device type canunderstand. There could be hundreds of device drivers pre-installed with the operating system,and the right ones for that particular computer set-up are loaded on boot-up.

User interface

A user interface, or UI, is a set of commands or menus accessible by the user and which hecan use to communicate with a program. The user interface is one of the most important parts ofany program because it determines how easily you can make the program do what you want. Thereare two main types of user interface: Currently personal computers encapsulate both functions insoftware.

Command Line Interface, or CLI: is a method of interacting with an operating system orsoftware using a command line interpreter. It is navigated by typing commands on a specified lineand then it receives a response back from the system, instead of using the mouse.

Graphical User Interface, or GUI: is a graphical user interface to a computer. It allows theuse of icons or other visual indicators to interact with and it uses windows, icons, and menus tocarry out commands, such as opening, deleting, and moving files. Although many GUI operatingsystems are navigated through the use of a mouse, the keyboard can also be utilized by usingkeyboard shortcuts or arrow keys.

System Utilities

A utility is a small program that provides an addition to the capabilities provided by theoperating system. Operating systems contain a number of utilities for managing disk drives,printers, and other devices. It is a special and non-essential part of the operating system. It's notabsolutely required to run programs and, if it didn't come with the operating system, you could addit. For example, print spool services, cryptographic password management and file managementservices.

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Types of operating system

Batch operating system

A batch processing is a group ofprocessing system in which all the requiredinput of all processing tasks is providedinitially. The users of a batch operatingsystem do not interact with the computerdirectly. Each user prepares his job on anoff-line device like punch cards and submitsit to the computer operator. To speed upprocessing, jobs with similar needs arebatched together and run as a group. The programmers leave their programs with the operator andthe operator then sorts the programs with similar requirements into batches. The main function ofa batch processing system is to automatically keep executing the jobs in a batch. The result of alltasks is provided after the completion of all the processing. It is old processing technique and rarelyused at present.

The problems with Batch Systems are:

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.

Difficult to provide the desired priority.

Time-sharing operating systems

Time-sharing is a technique which enablesmany people, located at various terminals, to use aparticular computer system at the same time. In otherwords, this refers to the allocation of computerresources in time slots to several programssimultaneously. The users feel that they are exclusiveuser of the CPU. Processor's time which is sharedamong multiple users simultaneously is termed astime-sharing. Multiple jobs are executed by the CPU by switching between them, but the switchesoccur so frequently. Thus, the user can receive an immediate response.

The main difference between a multi programmed batch system and a time-sharing systemis that in case of multi programmed batch systems, the objective is to maximize processor use,

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whereas in time-sharing systems, the objective is to minimize response time. Computer systemsthat were designed primarily as batch systems have been modified to time-sharing systems.

Multiuser Operating System

A multi-user operating system is an operating system that allows multiple users on differentcomputers or terminals to access a single system withone O.S. on it. These programs are often quitecomplicated and must be able to properly manage thenecessary tasks required by the different usersconnected to it. The users will typically be atterminals or computers that give them access to thesystem through a network, as well as other machineson the system such as printers. A multi-user operatingsystem differs from a single-user system on a networkin that each user is accessing the same O.S. atdifferent machines.

In a multiuser O.S., more than one user can use the same system at a same time through themulti I/O terminal or through the network. A multiuser O.0.S uses timesharing to supportmultiple users.

Multitasking Operating System

Multitasking is allowing a user toperform more than one computer task(such as the operation of an applicationprogram) at a time. The operating systemis able to keep track of where you are inthese tasks and go from one to the otherwithout losing information. In amultitasking operating system, more thanone task can be performed at the sametime but they are executed one afteranother through a single CPU. This term is used in modern operating systems when multiple tasksshare a common processing resource multitasking O.S. are of two types:

Pre-emptive multitasking: the O.S. allows CPU times slice to each program. After each timeslice, CPU executes another task.

Co-operative multitasking: a task can control CPU as long as it requires. However, it will freeCPU to execute another program if it doesn’t require CPU.

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Multiprocessing Operating System

A multiprocessing O.S. can support the executionof multiple processes at the same time. It uses multiplenumber of CPU. Multiprocessing is the coordinatedprocessing of programs by more than one computerprocessor. It is expensive in cost however the processingspeed will be faster. It is complex in its execution.Multiprocessing should not be confused withmultiprogramming.

Multiprocessing is divided into symmetric multiprocessing (SMP) and massively parallelprocessing (MPP). In symmetric multiprocessing, the processors share memory and the I/O bus ordata path. A single copy of the operating system is in charge of all the processors. SMP does notusually exceed 16 processors. In massively parallel processing, up to 200 or more processors canwork on the same application. Each processor has its own operating system and memory, but an"interconnect" arrangement of data paths allows messages to be sent between processors.

Multiprogramming Operating System

Multiprogramming is a rudimentary formof parallel processing in which several programsare run at the same time on a uniprocessor. Sincethere is only one processor, there can be no truesimultaneous execution of different programs.Instead, the operating system executes part of oneprogram, then part of another, and so on. To theuser it appears that all programs are executing atthe same time. In a multiprogramming O.S. more than one program can be used at the same time.It may or may not be multiprocessing. In a single CPU system, multiple programs are executed oneafter another by dividing the CPU into small time slice. The main idea of multiprogramming is tomaximize the use of CPU time.

Multithreading Operating System

Multithreading operating system is capable of executingdifferent parts of a program, called threads, simultaneously.This increases operating speed but also increases thecomplexity. However, the programmer must carefully designthe program in such a way that all the threads can run at thesame time without interfering with each other.

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Network Operating SystemA Network Operating System, or NOS, runs on a server and provides the server the

capability to manage data, users, groups, security,applications, and other networking functions. Theprimary purpose of the network operating system is toallow shared file and printer access among multiplecomputers in a network, typically a local area network(LAN), a private network or other networks. It isdesigned primarily to support workstation, personalcomputer, and older terminals.

The advantages of network operating systems are:

Security is server managed.

Upgrades to new technologies and hardware can be easily integrated into the system.

Remote access to servers is possible from different locations and types of systems.

The disadvantages of network operating systems are:

High cost of buying and running a server.

Dependency on a central location for most operations.

Regular maintenance and updates are required.

Real-Time operating System

A real-time system is defined as a data processing system in which the time intervalrequired to process and respond to inputs is so small that it controls the environment. It has verylittle user-interface capability, and no end-user utilities. The time taken by the system to respond toan input and display of required updated information is termed as the response time. So, in thismethod, the response time is very less as compared to online processing. Real-time systems areused when there are rigid time requirements on the operation of a processor or the flow of data andreal-time systems can be used as a control device in a dedicated application. There are two types ofreal-time operating systems.

Hard real-time systems: these systems guarantee that critical tasks complete on time. Inhard real-time systems, secondary storage is limited or missing and the data is stored inROM. In these systems, virtual memory is almost never found.

Soft real-time systems: these systems are less restrictive. A critical real-time task getspriority over other tasks and retains the priority until it completes. Soft real-time systemshave limited utility than hard real-time systems.

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Examples Computer of Operating Systems

Open-Source Computer Operating System

Linux

Linux is a Unix-like computer operating systemassembled under the model of free and open-source softwaredevelopment and distribution by Linus Torvalds and friendsthat was first announced August 25, 1991.The Linux kernel runs on numerous different platformsincluding the Intel and Alpha platform and is available underthe GNU, General Public License.

The system can be distributed, used, and expandedfree of charge. In this way, developers have access to allthe source codes, thus being able to integrate new functionsor to find and eliminate programming bugs quickly.Thereby drivers for new adapters (SCSI controller, graphics cards, etc.) can be integrated veryrapidly. Presently, Linux is successfully being used by several millions of users worldwide. Thecomposition of users varies from private users, training companies, universities, research centers,and companies.

Linux has the largest installed base of all general-purpose operating systems. It is also theleading operating system on servers and other big iron systems such as mainframe computers andvirtually all fastest supercomputers. Below are some examples of where Linux is used today:

Android phones and tablets - Android phones and tablets use a form of Linux.

Servers - A vast majority of the web servers that run many web pages (including this one)are using Linux.

TV, Cameras, DVD players, etc. - Most of the appliances that use some form of a computeruse Linux.

Amazon - Many of the computers that help run Amazon use Linux.

Google - Computers that help run Google and Google search results use a Linux.

Planes - Airplanes computers and screens you watch on the plane use Linux.

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The most popular Linux distributions are:

- Debian is a free, open-source operating system developed with tools from the GNUproject. It can be run using either the Linux or the FreeBSD kernel. Debian includes many popularfree software titles by default, such as LibreOffice, Ice weasel (a variant of Firefox), and Evolutionmail.

- Ubuntu is a Debian-based Linux operating system for personal computers, tablets andsmartphones. A default installation of Ubuntu contains a wide range of software that includesLibre Office, Firefox, Thunderbird, Transmission, and several lightweight games such as Sudokuand chess. Many additional software packages are accessible from the built-in Ubuntu SoftwareCenter as well as any other APT-based package management tool.

- Google Chrome OS, or Chrome OS, is a Linux-based operating system developed byGoogle to work exclusively with online web applications.

- Fedora is a Linux variant created by a community of developers known as the FedoraProject. The design focus of Fedora is security and innovation. It has a reputation for integratingthe newest changes to operating system technologies as early as possible. Fedora is also noted forimplementing SE Linux (Security-Enhanced Linux), which enforces mandatory access controls onall files.

Proprietary Computer Operating System

A proprietary design or technique is one that is owned by a company. It also implies that thecompany has not divulged specifications that would allow other companies to duplicate thisproduct.

UNIXUnix is a family of multitasking, multiuser computer operating systems that derive from the

original AT&T Unix, developed in the 1970s at theBell Labs research center by Ken Thompson,Dennis Ritchie, and others. The UNIX system iscomposed of several components that wereoriginally packaged together. By including thedevelopment environment, libraries, documentsand the portable, modifiable source code for all ofthese components, in addition to the kernel of anoperating system, Unix was a self-containedsoftware system. This was one of the key reasons it emerged as an important teaching and learningtool and has had such a broad influence.

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Mac OSThe Mac OS, or MacOS, is an operating system that was

designed for the Apple Macintosh computer. It was developedby Apple Inc., who also created Apple I, as well as a number ofother more modern products including the iPod, iPhone, andiPad. The main competition to the Mac OS is the Windowsoperating system, the most popular OS by a large margin. TheMac OS only runs on Apple Desktop and Laptop co2mputers.The iPod, iPhone, and iPad use a different operating systemknown as iOS. A popular feature of its latest version, Mac OS X ,is a desktop interface with some 3-D appearance characteristics.OS X has a modular design intended to make it easier to addnew features to the operating system in the future. It runs UNIXapplications as well as older Mac applications.

MS DOS (not actually used)MS DOS (Disk Operating System) is

one of the first operating systems for thepersonal computer. It is an acronym for severalcomputer operating systems that are operatedby using the command line. When you turnedthe computer on all you saw was the commandprompt which looked like c:\ >.

It was developed for IBM by MicrosoftCorporation, which also produced its ownalmost identical version called MS-DOS. Theseearly operating systems did not multitask, asthey were only able to run one program at atime. The command line interface, in which a user must type in commands, required the user toremember commands to run programs or do other operating system tasks, making it difficult fornovices to use. Subsequent versions have become increasingly sophisticated as they incorporatedfeatures of minicomputer operating systems. However, DOS is still a 16-bit operating system anddoes not support multiple users or multitasking.

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Windows Microsoft Windows (or simply Windows) is a

meta-family of graphical operating systems developed,marketed, and sold by Microsoft. It consists of severalfamilies of operating systems, each of which cater to acertain sector of the computing industry with the OStypically associated with IBM PC compatiblearchitecture. It provides a graphical user interface (GUI),virtual memory management, multitasking, and supportfor many peripheral devices. In addition to Windows OSfor personal computers, Microsoft also offers operatingsystems for servers and personal mobile devices. ActiveWindows families include Windows NT, WindowsEmbedded and Windows Phone. It dominates the personal computer world, running, by someestimates, more than 90 percent of all personal computers (the remainder running Linux and Macoperating systems).

This type of operating system is said to have WIMP features:

-Windows

-Icons

-Menus

-Pointing device (mouse)

Percentage of Users of Operating Systems in computers

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Examples of Mobile Operating Systems

Open-Source Mobile Operating Systems

Android OS (Google Inc.)The Android mobile operating system is

Google's open and free software stack that includes anoperating system, middleware and also key applicationsfor use on mobile devices, including smartphones.Updates for the open source Android mobile operatingsystem have been developed under “dessert-inspired”codenames (Cupcake, Donut, Eclair, Gingerbread,Honeycomb, Ice Cream Sandwich) with each newversion arriving in alphabetical order with newenhancements and improvements.

MeeGo OS (Nokia and Intel)

A joint open source mobile operatingsystem which is the result of merging two productsbased on open source technologies: Maemo(Nokia) and Moblin (Intel). MeeGo is a mobile OSdesigned to work on a number of devices includingsmartphones, netbooks, tablets, in-vehicleinformation systems and various devices usingIntel Atom and ARMv7 architectures.

Proprietary Mobile OperatingSystems

iPhone OS / iOS (Apple Inc.)

Apple's iPhone OS was originally developed for useon its iPhone devices. Now, the mobile operating system isreferred to as iOS and is supported on a number of Appledevices including the iPhone, iPad, iPad 2 and iPod Touch.The iOS mobile operating system is available only onApple's own manufactured devices as the company does notlicense the OS for third-party hardware. Apple iOS isderived from Apple's Mac OS X operating system.

Symbian OS (Nokia)

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Symbian is a mobile operating system (OS) targetedat mobile phones that offers a high-level of integration withcommunication and personal information management(PIM) functionality. Nokia has made the Symbian platformavailable under an alternative, open and direct model, towork with some OEMs and the small community of platformdevelopment collaborators. Nokia does not maintainSymbian as an open source development project.

BlackBerry (Research in Motion)

The BlackBerry OS is a proprietary mobile operatingsystem developed by Research in Motion for use on thecompany’s popular BlackBerry handheld devices. TheBlackBerry platform is popular with corporate users as itoffers synchronization with Microsoft Exchange, LotusDomino, Novell GroupWise email and other businesssoftware, when used with the BlackBerry Enterprise Server.

Windows Mobile (Windows Phone 7)

Windows Mobile is Microsoft's mobileoperating system used in smartphones and mobiledevices – with or without touchscreens. TheMobile OS is based on the Windows CE 5.2 kernel.In 2010 Microsoft announced a new smartphoneplatform called Windows Phone 7.

Percentage of Users of Mobile Operating Systems

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Examples of Server Operating System

Proprietary Server Operating Systems

Mac OS X Server

Mac OS X Server is Apple's Unix server operating system. OS X Server shares anumber of components with FreeBSD, and most Linux apps can be recompiled fairly easilyto run on OS X. According to Apple, Mac OS X Server's full Unix conformance ensurescompatibility with existing server and application software. Mac OS X Server includesadditional services, applications, and administration tools for managing and deployingservers. It's commonly found in small business, education, and large organizations. Web-based collaboration, system imaging, live video broadcasting and on-demand videostreaming, podcast encode and delivery, client management, and distributed computing.

Windows Small Business Server 2008

Microsoft's Windows Small Business Server is an integrated server suite that runsthe network infrastructure of companies that have fewer than 75 workstations or users.Application server technologies are tightly integrated to enable small businesses withtargeted solutions and offer management benefits such as e-mail, Internet connectivity,internal Web sites, remote access, support for mobile devices, file and printer sharing,backup, and restore. The 2008 version is updated to use 64-bit Server 2008 and Exchange2007.

Open-Source Server Operating Systems

Linux

The server edition of Ubuntu Linux is free. Backed by the well-funded, for-profitcompany Canonical, Ubuntu Linux has emerged from relative obscurity to join the top tierof business Linux options. As Mighty Matthew McKenzie said, "Ubuntu has worked hardto position itself as a good choice for smaller companies that want to minimize their up-front costs without sacrificing the ability to get professional service and support when theyneed it." He adds that subscription-based distros are an option for companies that willprobably heavily rely on a vendor's service and support. Subscription-based distros mightalso provide a safety net for IT departments that need to "sell" a Linux deployment to risk-averse, non-IT decision makers.

FreeBSD

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FreeBSD is developed and maintained by a team of people. It's derived from BSD, aversion of Unix, and, obviously, FreeBSD is free. The open source FreeBSD has been toutedas being ideal for high-performance network applications as well as being easy to use. It'sthe free OS listed most often in Netcraft's list of the 50 Web servers with the longestuptime (meaning no crashes have occurred and no kernel updates have been deemedneeded). FreeBSD includes SCTP, UFS journaling, an experimental port of Sun's ZFS filesystem, GCC4, improved support for the ARM architecture and major updates andoptimizations relating to network, audio, and SMP performance.

Open Solaris

Sun Microsystems has heavily marketed Solaris for use with its own x64workstations and servers based on AMD Opteron and Intel Xeon processors, as well as x86systems manufactured by companies such as Dell, Hewlett-Packard, Intel, Fujitsu Siemens,and IBM. The Open Solaris operating system is a free, open source release that offers arange of support options for businesses. The latest enhancements to Open Solaris includeZFS, Solaris Containers, and Predictive Self-Healing.

Percentage of Users of Server Operating Systems

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"History of Operating Systems." Index of /. Accessed November 8, 2016. http://www.personal.kent.edu/~rmuhamma/OpSystems/Myos/osHistory.htm

"Timeline of Operating Systems - Wikipedia." Wikipedia, the Free Encyclopedia. Accessed November 8, 2016. https://en.wikipedia.org/wiki/Timeline_of_operating_systems

Functions & Tasks of Operating Systems

"User Interface - Wikipedia." Wikipedia, the Free Encyclopedia. Accessed November 8, 2016. https://en.wikipedia.org/wiki/User_interface

"What is API - Application Program Interface? Webopedia." Webopedia: Online Tech Dictionary for IT Professionals. Accessed November 8, 2016. http://www.webopedia.com/TERM/A/API.html

"Operating System Overview." Www.tutorialspoint.com. Accessed November 8, 2016. https://www.tutorialspoint.com/operating_system/os_overview.htm

"Operating Systems Services and Functions." UzEE's Journal. Accessed November 8, 2016. https://uzeeinc.wordpress.com/2007/11/04/operating-systems-services-and-functions/

Services of Operating Systems

"Operating System - Services." Www.tutorialspoint.com. Accessed November 8, 2016. https://www.tutorialspoint.com/operating_system/os_services.htm

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"Operating Systems Notes." Index of /. Accessed November 8, 2016. http://www.personal.kent.edu/~rmuhamma/OpSystems/Myos/sysService.htm

"Operating Systems Services and Functions." UzEE's Journal. Accessed November 8, 2016. https://uzeeinc.wordpress.com/2007/11/04/operating-systems-services-and-functions/

Components of Operating Systems

"Define Operating System. What Are the Functions and Types of Operating Systems?" ENotes. Accessed November 8, 2016. http://www.enotes.com/homework-help/define-operating-system-write-down-function-types-128847

"Teach-ICT A Level Computing OCR Exam Board - Features of Operating System." Teach ICT Computer Science and ICT Revision. Accessed November 8, 2016. http://www.teach-ict.com/as_as_computing/ocr/H447/F453/3_3_1/features_of_os/miniweb/pg9.htm

"What is Kernel (Operating System Kernel)? Webopedia Definition." Webopedia: Online Tech Dictionary for IT Professionals. Accessed November 8, 2016. http://www.webopedia.com/TERM/K/kernel.html

"What is Kernel? - Definition from Techopedia." Techopedia.com. Accessed November 8, 2016. https://www.techopedia.com/definition/3277/kernel

"What is Kernel? - Definition from WhatIs.com." SearchEnterpriseLinux. Accessed November 8, 2016. http://searchenterpriselinux.techtarget.com/definition/kernel

"What is Kernel?" Computer Hope's Free Computer Help. Accessed November 8, 2016. http://www.computerhope.com/jargon/k/kernel.htm

"Teach-ICT A Level Computing OCR Exam Board - Features of Operating System." Teach ICT Computer Science and ICT Revision. Accessed November 8, 2016. http://www.teach-ict.com/as_as_computing/ocr/H447/F453/3_3_1/features_of_os/miniweb/pg9.htm

"What is Device Driver? - Definition from WhatIs.com." SearchEnterpriseDesktop. Accessed November 8, 2016. http://searchenterprisedesktop.techtarget.com/definition/device-driver

"What is Device Driver?" Computer Hope's Free Computer Help. Accessed November 8, 2016. http://www.computerhope.com/jargon/d/driver.htm

"What is UI (User Interface)?" Computer Hope's Free Computer Help. Accessed November 8, 2016. http://www.computerhope.com/jargon/u/ui.htm

"What is User Interface (UI)? - Definition from WhatIs.com." SearchSOA. Accessed November 8, 2016. http://searchsoa.techtarget.com/definition/user-interface

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"What is User Interface (UI)? Webopedia Definition." Webopedia: Online Tech Dictionary for IT Professionals. Accessed November 8, 2016. http://www.webopedia.com/TERM/U/user_interface.html

"What is Command Line Interface (CLI)? - Definition from WhatIs.com." SearchWindowsServer. Accessed November 8, 2016. http://searchwindowsserver.techtarget.com/definition/command-line-interface-CLI

"What is Command Line?" Computer Hope's Free Computer Help. Accessed November 8, 2016. http://www.computerhope.com/jargon/c/commandi.htm

"What is Graphical User Interface (GUI)?" Computer Hope's Free Computer Help. Accessed November 8, 2016. http://www.computerhope.com/jargon/g/gui.htm

"What is GUI - Graphical User Interface? Webopedia Definition." Webopedia: Online Tech Dictionary for IT Professionals. Accessed November 8, 2016. http://www.webopedia.com/TERM/G/Graphical_User_Interface_GUI.html

"What is GUI (graphical User Interface)? - Definition from WhatIs.com." SearchWinDevelopment. Accessed November 8, 2016. http://searchwindevelopment.techtarget.com/definition/GUI

"What is Utility (Utility Program)? Webopedia Definition." Webopedia: Online Tech Dictionary forIT Professionals. Accessed November 8, 2016. http://www.webopedia.com/TERM/U/utility.html

"What is Utility? - Definition from WhatIs.com." WhatIs.com. Accessed November 8, 2016. http://whatis.techtarget.com/definition/utility

"What is Utility?" Computer Hope's Free Computer Help. Accessed November 8, 2016. http://www.computerhope.com/jargon/u/utility.htm

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Types of Operating Systems

"What is Batch Processing Operating System?" Computer Notes. Accessed November 8, 2016. http://ecomputernotes.com/fundamental/disk-operating-system/batch-processing-operating-system

"Time Sharing Operating System." Computer Notes. Accessed November 8, 2016. http://ecomputernotes.com/fundamental/disk-operating-system/time-sharing-operating-system

"Teach ICT - GCSE ICT - Types of Operating Systems, Single User Operating Systems, Multi User Operating Systems, Online Operating Systems." Teach ICT Computer Science and ICT Revision. Accessed November 8, 2016. http://www.teach-ict.com/gcse_new/computer%20systems/operating_system_types/miniweb/pg3.htm

"What is a Multi-User Operating System? (with Pictures)." WiseGEEK. Accessed November 8, 2016.http://www.wisegeek.com/what-is-a-multi-user-operating-system.htm#didyouknowout

"Definition of Multitasking Operating System." Computer Notes. Accessed November 8, 2016. http://ecomputernotes.com/fundamental/disk-operating-system/multitasking-operating-system

"What is Multitasking? - Definition from WhatIs.com." WhatIs.com. Accessed November 8, 2016. http://whatis.techtarget.com/definition/multitasking

"What is Multitasking? Webopedia Definition." Webopedia: Online Tech Dictionary for IT Professionals. Accessed November 8, 2016. http://www.webopedia.com/TERM/M/multitasking.html

"What is Preemptive Multitasking? - Definition from WhatIs.com." WhatIs.com. Accessed November 8, 2016. http://whatis.techtarget.com/definition/preemptive-multitasking

"What is Multiprocessing? - Definition from WhatIs.com." SearchDataCenter. Accessed November 8, 2016. http://searchdatacenter.techtarget.com/definition/multiprocessing

"What Is a Multiprogramming Operating System? (with Picture)." WiseGEEK. Accessed November 8, 2016. http://www.wisegeek.com/what-is-a-multiprogramming-operating-system.htm

"What is Multiprogramming? - Definition from WhatIs.com." WhatIs.com. Accessed November 8, 2016. http://whatis.techtarget.com/definition/multiprogramming

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"What is Multithreading? - Definition from WhatIs.com." WhatIs.com. Accessed November 8, 2016. http://whatis.techtarget.com/definition/multithreading

"What is Multithreading? Webopedia Definition." Webopedia: Online Tech Dictionary for IT Professionals. Accessed November 8, 2016. http://www.webopedia.com/TERM/M/multithreading.html

"What is a Network Operating System (NOS)? - Definition from Techopedia." Techopedia.com. Accessed November 8, 2016. https://www.techopedia.com/definition/3399/network-operating-system-nos

"What is Network Operating System (NOS)? - Definition from WhatIs.com." SearchNetworking. Accessed November 8, 2016. http://searchnetworking.techtarget.com/definition/network-operating-system

"What is Network Operating System (NOS)? Webopedia Definition." Webopedia: Online Tech Dictionary for IT Professionals. Accessed November 8, 2016. http://www.webopedia.com/TERM/N/network_operating_system_NOS.html

"What is a Real-Time Operating System (RTOS)? - National Instruments." National Instruments: Test, Measurement, and Embedded Systems - National Instruments. Accessed November 8,2016. http://www.ni.com/white-paper/3938/en/

"What is Real-time Operating System (RTOS)? - Definition from WhatIs.com." SearchDataCenter. Accessed November 8, 2016. http://searchdatacenter.techtarget.com/definition/real-time-operating-system

"What is RTOS (Real-Time Operating System)?" Computer Hope's Free Computer Help. Accessed November 8, 2016. http://www.computerhope.com/jargon/r/realsyst.htm

Examples 0f Computer Operating Systems

"DOS - Wikipedia." Wikipedia, the Free Encyclopedia. Accessed November 8, 2016. https://en.wikipedia.org/wiki/DOS

"Examples of Operating Systems." Calvin College | Grand Rapids, Michigan. Accessed November 8, 2016. http://www.calvin.edu/~rbobeldy/tutorials/os/basics2.htm

"The History of Windows Operating Systems - Webopedia." Webopedia: Online Tech Dictionary for IT Professionals. Accessed November 8, 2016 http://www.webopedia.com/DidYouKnow/Hardware_Software/history_of_microsoft_windows_operating_system.html

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"Linux - Wikipedia." Wikipedia, the Free Encyclopedia. Accessed November 8, 2016. https://en.wikipedia.org/wiki/Linux

"What is Debian?" Computer Hope's Free Computer Help. Accessed November 22, 2016. http://www.computerhope.com/jargon/d/debian.htm

"What is Fedora Linux?" Computer Hope's Free Computer Help. Accessed November 22, 2016. http://www.computerhope.com/jargon/f/fedora-linux.htm

"What is Google Chromebook and Chrome OS?" Computer Hope's Free Computer Help. Accessed November 22, 2016. http://www.computerhope.com/jargon/c/chromebook.htm

"Macintosh Operating Systems - Wikipedia." Wikipedia, the Free Encyclopedia. Accessed November 8, 2016. https://en.wikipedia.org/wiki/Macintosh_operating_systems

"Microsoft Windows - Wikipedia." Wikipedia, the Free Encyclopedia. Accessed November 8, 2016. https://en.wikipedia.org/wiki/Microsoft_Windows

"Unix - Wikipedia." Wikipedia, the Free Encyclopedia. Accessed November 8, 2016. https://en.wikipedia.org/wiki/Unix

"What is DOS (Disk Operating System)? - Definition from WhatIs.com." SearchSecurity. Accessed November 8, 2016 http://searchsecurity.techtarget.com/definition/DOS

"What is Linux?" Opensource.com. Accessed November 8, 2016. https://opensource.com/resources/what-is-linux

"What is Mac OS? - Definition from WhatIs.com." WhatIs.com. Accessed November 8, 2016. http://whatis.techtarget.com/definition/Mac-OS

"What is MacOS?" Computer Hope's Free Computer Help. Accessed November 8, 2016. http://www.computerhope.com/jargon/m/macos.htm

Examples 0f Mobile Operating Systems

"Mobile Operating Systems (Mobile OS) Explained by Webopedia.com." Webopedia: Online Tech Dictionary for IT Professionals. Accessed November 22, 2016. http://www.webopedia.com/DidYouKnow/Hardware_Software/mobile-operating-systems-mobile-os-explained.html

"Top 10 Mobile Phones Operating Systems." ShoutMeLoud. Accessed November 22, 2016. http://www.shoutmeloud.com/top-mobile-os-overview.html

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Examples 0f Server Operating Systems

"5 Server Operating Systems For Your Business." Entrepreneur. Accessed November 22, 2016. https://www.entrepreneur.com/article/200856

"What is a Server Operating System (Server OS)? - Definition from Techopedia." Techopedia.com. Accessed November 22, 2016. https://www.techopedia.com/definition/30145/server-operating-system-server-os

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