Computer Science
Operating Systems
Operating systems are software that manage computer hardware and provide services for applications. They act as an intermediary between the user and the computer hardware, handling tasks such as memory management, process scheduling, and file management. Examples of operating systems include Windows, macOS, and Linux.
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eBook - PDFThe Architecture of Computer Hardware, Systems Software, and Networking
An Information Technology Approach
- Irv Englander, Wilson Wong(Authors)
- 2021(Publication Date)
- Wiley(Publisher)
These included programs are known collectively as an operating system. The operating system acts as a system manager, controlling both hardware and software and acting as an interface between the user and the system. The operating sys- tem itself consists of a collection of programs that work together collectively to accomplish these tasks. An operating system may be defined as a collection of computer programs that integrate the hardware resources of the computer and make those resources available to a user and the user’s programs, in a way that allows the user access to the computer in a productive, timely, and efficient manner. In other words, the operating system acts as an intermediary between the user and the user’s programs and the hardware of the computer. It makes the resources available to the user and the user’s programs in a convenient way, on the one hand, and controls and man- ages the hardware, on the other. Intuitively we think of a user as a human interacting with a computer system; however, there are situations in which the “user” is actually another computer or a mechanical or electronic device of some sort. A common example of this situation is one in which an appli- cation program on one computer requests services from an application program or system service on another machine, for example, a Web server application requesting data from a back-end database server. Another example would be a situation in which a user on a client machine requests file or printer services on a server machine. In serving as an intermediary between the users of computer services and the computer’s resources, the operating system provides three basic types of services: 1. Command services. It accepts and processes commands and requests from the user and the user’s programs and presents appropriate output results. 2. Program services. It manages, loads, and executes programs.
eBook - PDF- Adele Kuzmiakova(Author)
- 2023(Publication Date)
- Arcler Press(Publisher)
FUNDAMENTALS OF Operating Systems 7 CONTENTS 7.1. Introduction .................................................................................... 200 7.2. Computer System Organization ...................................................... 201 7.3. Computer System Structure ............................................................. 204 7.4. Operating System (OS) History ....................................................... 204 7.5. Operating System (OS) Functions.................................................... 205 7.6. Operating System (OS) Categories .................................................. 206 7.7. The Performance Development of OS ............................................. 209 7.8. Operating System (OS) Service ....................................................... 212 7.9. Operating System (OS) Operations ................................................. 212 7.10. Operating System (OS) Components ............................................. 214 References ............................................................................................. 217 CHAPTER Key Dynamics in Computer Programming 200 7.1. INTRODUCTION An operating system (OS) is a collection of programs that manage the execution of application software and serve as a link between a computer’s consumer and its hardware. The OS is software that both maintains computer hardware and offers an environment in which application applications may execute (Eager et al., 2016). Windows/NT, Windows, MacOS, and OS/2 are instances of OSs. The operating system goals are as follows (Hughes, 2000): • To design the computer system user-friendly and simple to operate; • To make the most use of computer hardware; • To run user applications and make it simpler to solve user issues. Application programs, OSs, hardware, and users are the 4 elements that make up a computer system. Figure 7.1 depicts an abstract representation of system elements (Dandamudi, 2003).
eBook - PDF- Ann McHoes, , Ida M. Flynn, , Ann McHoes, Ida M. Flynn(Authors)
- 2017(Publication Date)
- Cengage Learning EMEA(Publisher)
All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-300 4 Chapter 1 | Introducing Operating Systems To understand an operating system is to begin to understand the workings of an entire computer system, because the operating system software manages each and every piece of hardware and software. In the pages that follow, we explore what Operating Systems are, how they work, what they do, and why. This chapter briefly describes the workings of Operating Systems on the simplest scale. The following chapters explore each component in more depth, and show how its func-tion relates to the other parts of the operating system. In other words, we see how the pieces work together harmoniously to keep the computer system working smoothly. What Is an Operating System? A computer system typically consists of software (programs) and hardware (the tangible machine and its electronic components). The operating system is the most important software— it’s the portion of the computing system that manages all of the hardware and all of the other software. To be specific, the operating system software controls every file, every device, every section of main memory, and every moment of process-ing time. It controls who can use the system and how. In short, the operating system is the boss. Therefore, each time the user sends a command, the operating system must make sure that the command is executed; or, if it’s not executed, it must arrange for the user to get a message explaining the error. This doesn’t necessarily mean that the operating system executes the command or sends the error message, but it does control the parts of the system that do. Operating System Software The pyramid shown in Figure 1.1 is an abstract representation of the operating system in its simplest form, and demonstrates how its major components typically work together.
eBook - PDF- Michael Tooley(Author)
- 2013(Publication Date)
- Newnes(Publisher)
Unix, VMS, and MVS, are compared. Finally, multiprocessing and distributed systems are reviewed, with examples drawn from MVS (which can also be a multiproc-essing system) and a multiprocessing adaptation of Unix. Lastly, the ways the programmer can access operating system services are discussed. 3.2 Basic concepts of Operating Systems An operating system is the software which intervenes, at the lowest level, between the hardware of the machine itself, its peripherals, any applications software, possibly sensors and ac-tuators in the 'real' world and, of course, the 'user'. The 'user' means primarily the software engineer, the programmer, systems programmer or systems manager, but not the end user, who often perceives only the 'system' presented by an application. The operating system acts as an intermediary between the require- Operating Systems 115 ments of the hardware and the needs of the programmer. It removes from the programmer the need to be concerned with the low-level details of data transfer from main memory to a second-ary storage device and it coordinates the disparate elements of the machine's operating environment, acting as a scheduler of work, an arbiter (on multi-user systems) between the conflicting de-mands and needs of users and a protector, ensuring that one process cannot corrupt another. In addition, the operating system presents most users with some kind of interface (unless a more indirect interface is pro-vided for an end user solely by an application program, as is in the case, for example, in form-filling programs for data entry pur-poses) usually called the command interface, in the form of a set of commands or menu-choices. The command interface in turn arbitrates between the user and a series of general-purpose utility programs (which provide simple, basic services such as a file maintenance, printing services and so on) and those applications programs which can be invoked by the command interface.
eBook - PDFInformation Technology
Made Simple
- Roger Carter(Author)
- 2013(Publication Date)
- Made Simple(Publisher)
5.1 What is system software? When we apply a computer to the task of writing a letter or keeping records, we use application software. That applica-tion software resides in the computer's memory alongside a more basic level of software called system software. The application software does not have to tell the computer exactly how to access a disk or keyboard or control the screen display, as the system software looks after this. System software is fundamental to the computer - when you buy the computer, you also buy this software - for without it the computer can't do anything. System software is made up of the operating system, a number of additional utilities, and, on many computers, software which provides a user-friendly operating environment. • The operating system controls the disk-drives and other hardware devices and, in the case of networked com-puters, the network operations. It also allows you to carry out computer housekeeping tasks such as loading, copying, and deleting files. • The operating environment provides an easy-to-use way of carrying out housekeeping tasks as well as providing friendly environment within which computer applica-tions can be run. • Utilities provide additional facilities and routines. In this chapter we'll look at each of these three types of systems software. The next chapter introduces application software. 5 System software 96 Information Technology 5.2 Operating Systems A computer's operating system enables it to carry out its disk filing and other operational tasks. We can put these tasks under five headings: • Basic input/output operations, such as controlling the screen display. This is governed by the part of the operating system often known as the BIOS (Basic Input/ Output System). • Disk operations, which are to do with storing programs and data on disk. This is governed by the part of the operating system which on PCs is called DOS (Disk Operating System).
No longer available |Learn more- (Author)
- 2014(Publication Date)
- White Word Publications(Publisher)
________________________ WORLD TECHNOLOGIES ________________________ Chapter 2 Operating System An operating system ( OS ) is software, consisting of programs and data, that runs on computers and manages computer hardware resources and provides common services for efficient execution of various application software. For hardware functions such as input and output and memory allocation, the operating system acts as an intermediary between application programs and the computer hardware, although the application code is usually executed directly by the hardware and will frequently call the OS or be interrupted by it. Operating Systems are 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 for personal computers are (in alphabetical order): GNU/Linux, Mac OS X, Microsoft Windows and Unix Types of Operating Systems Real-time Operating System : It 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 behavior. The main object of real-time Operating Systems is their quick and predictable response to events. They either have an event-driven or a time-sharing design. An event-driven system switches between tasks based on their priorities while time-sharing Operating Systems switch tasks based on clock interrupts. Multi-user and Single-user Operating Systems : The Operating Systems of this type allow a multiple users to access a computer system concurrently. Time-sharing system can be classified as multi-user systems as they enable a multiple user access to a computer through the sharing of time. Single-user Operating Systems, as opposed to a multi-user operating system, are usable by a single user at a time.
eBook - PDF- Greg Tomsho(Author)
- 2020(Publication Date)
- Cengage Learning EMEA(Publisher)
MacOS is popular with home users because the desktop is intuitive and home network setup is user friendly. Also, some home users are already familiar with macOS from using it at school. The Mac screenshots and features covered in this book are based on macOS Mojave. In Module 2, you will take a much closer look at the individual Operating Systems mentioned here. In that module, you will find out more about the hardware required to run each operating system, and which versions you will see in which environments. Try the hands-on projects at the end of Module 1 to learn more about Windows-based, Linux, and macOS Operating Systems, including how to use tools for obtaining system information, how to view device drivers, how to see multitasking in operation, and how to use desktop applications. Module Summary • All computers perform three basic tasks: input, processing, and output. An operating system is a specialized computer program that provides a user interface, file system, processes and services, and a kernel. • An operating system provides the foundation upon which to run the components of a computer and execute applications. • A basic task of an operating system is to enable a computer to perform I/O functions so that it can use software applications and communicate with computer hardware. • Operating Systems can be understood in terms of characteristics such as time sharing, real- time operation, and multiuser capabilities. • Early Operating Systems tended to be single- tasking, but modern systems are largely multitasking. • A true multiuser system is one in which multiple users access and run a single application on a single computer at the same time. • Two common types of Operating Systems are desktop (or client) and server Operating Systems.
No longer available |Learn moreComputing Fundamentals
IC3 Edition
- Faithe Wempen(Author)
- 2014(Publication Date)
- Wiley(Publisher)
Part II Software Chapter.4 Operating System Basics Chapter.5 Introduction to Windows 7 Chapter.6 Windows 7 Administration and Maintenance Chapter.7 Understanding Application Software Chapter 4 Operating System Basics Learning objectives ◽ Understand the types of Operating Systems available ◽ Differentiate among the major desktop Operating Systems ◽ Explain how device drivers work ◽ Explain computer file storage concepts When you think about using a computer, you probably think about performing some useful task with it, or playing a game. Behind the scenes, though, is the soft-ware that keeps the computer running and responding to commands: the operat-ing system (OS). The operating system you use can make a big difference in how the computer behaves, how it respond to commands, what applications it can run, and what add-on hardware you can attach. By understanding the available Operating Systems and their benefits, you can make the right choice in selecting an operating system—or you can choose to purchase a device with the right operating system already built in. In this chapter, you will learn about system software in general, and how Operating Systems work. You’ll survey several popular Operating Systems and learn how they communicate with hardware, with the Internet, and with the user. You will also find out how computers store and manage files. Understanding System Software Comparing the Major Operating Systems Understanding Device Drivers Understanding Digital Storage 110 Part II: Software Programmer A programmer writes the instructions that become computer programs . Whether it’s an operating system, a utility, or a game, a programmer takes a general concept like “open a dialog box with user controls for adjusting the graphics quality” and makes it a reality by writing the exact instructions needed, line by line .
eBook - PDF- Palmer, Greg Tomsho(Authors)
- 2016(Publication Date)
- Cengage Learning EMEA(Publisher)
This makes the application programmer ’ s job easier because she does not have to know exactly how to manipulate the chips in the computer to communicate with the keyboard, monitor, or printer. She only has to know how to communicate with the operating system. 16 Chapter 1 Operating Systems Fundamentals Copyright 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-300 Software Hardware User Word processor Spreadsheet Screen Keyboard Mouse Serial Disks Others File system code Hard disk driver DVD/CD-ROM driver Monitor Printer Keyboard Mouse Modem Screen driver Keyboard driver Mouse driver Serial driver Print driver Application software Operating system Application programming interfaces (APIs) Disk driver code Hard disk controller DVD/CD-ROM controller Hard disk drive DVD/CD-ROM driver Figure 1-3 Application programs communicate with hardware through the operating system In its most basic form, an operating system ma nages the communication among the application programs, the user, and the computer. This level of management allows application program-mers to concentrate on applications that will ru n on any hardware, as long as the operating sys-tem can control them. In other words, an applic ation program can submit a general request to the operating system, such as “ write this information to disk, ” and the operating system handles the details. The applic ation programmer doesn ’ t have to worry about how to queue data, update the disk directory, or physically copy data from memory to the disk drive. In early Operating Systems, programmers designed code to directly access hardware and improve overall application performance. This practice can make hardware response fast, 1 Understanding How Operating Systems Work 17 Copyright 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-300
eBook - PDF- Henry M. Walker(Author)
- 2012(Publication Date)
- Chapman and Hall/CRC(Publisher)
Apple’s Operating Systems have allowed users, even begin-ning users, to easily perform valuable tasks, such as editing text, pictures, and sound. • Unix and Linux tout their reliability and ability to link complex processing tasks, with new graphical interfaces simplifying interactions with users. Proponents on each side could expand on these comments at great length (just ask them!). Each of these Operating Systems has its own strengths and advantages, and the choice of one over another depends on what a user wants to do and with whom that user wants to interact. Summary Operating Systems handle common tasks and administrative functions that allow users to run computers with relative ease. Such tasks include identifying one user from another, keeping track of distinct requests (e.g., associating typing in a window with the correct pro-cessing), scheduling and coordinating processing, allocating resources (e.g., files, printers, memory), handling files, and communicating with other machines. When these tasks are performed centrally, individual users need not worry about doing these tasks themselves. 130 ◾ The Tao of Computing Multitasking allows computers to split their processing time and resources among sev-eral processes or users. Processing requires coordination when computers work on several tasks at the same time. When starting a computer, the operating system must prepare for its role of coordination; this process is called booting. Rebooting involves shutting down a computer and staring it again. Although rebooting should be needed rarely, if ever, rebooting sometimes provides a convenient way to recover and move forward when malfunctions arise in processing. Because the oversight and administration of computers can be done in many ways, different Operating Systems have developed, including Microsoft Windows, Linux, and Macintosh OS X.
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