IBM, Hewlett-Packard, and other computer giants have embraced Linux and support its ongoing development. More than a decade after its initial release, Linux is being adopted worldwide mainly as a server platform. More and more people are starting to use Linux as a home and office desktop operating system. Anderson, Laurence. Coustan, Dave, and Curt Franklin. How Operating Systems Work.
How Stuff Works, Inc. Cite this article Pick a style below, and copy the text for your bibliography. August 18, Retrieved August 18, from Encyclopedia. Then, copy and paste the text into your bibliography or works cited list.
The Differences Between Mac, Windows, and Linux
Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, Encyclopedia. The operating system is software that manages every part of a computer system — all hardware and all other software.
To be specific, it controls every file, every device, every section of main memory, every nanosecond of processing time, and every network connection. It controls who can use the system and how.
Operating System (OS) Definition & Examples
In short, it is the boss — without it, nothing can happen. When a computer user sends a command by typing it from the keyboard or clicking with the mouse, the operating system must make sure that the command is executed. If it is not executed, the operating system must arrange for the user to receive a message, usually on the monitor, explaining. This does not 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. Every operating system, regardless of its size and complexity, can be represented by a pyramid showing how its five major functions called managers work together.
The memory manager, the processor manager, the device manager, and the file manager form the pyramid's base; network operating systems add a network manager as well. The user interface — the part of the operating system that communicates with the user — is supported by the other four or five managers.
These virtual managers must do more than perform their individual tasks. They must also be able to work harmoniously with every other manager. For example, they must be able to monitor their resources continuously, enforce the policies that determine who gets what, when, and how much, allocate their resources when it is appropriate, and de-allocate their resources — reclaim them — when appropriate.
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The memory manager is in charge of main memory, also known as random access memory RAM. It checks the validity of each request for memory space and, if it is a legal request, the memory manager allocates a portion that is not already in use. In a multi-user environment, the memory manager sets up a table to keep track of who is using which section of memory. Finally, when the time comes to reclaim the memory, the memory manager de-allocates the memory space. One of the manager's primary responsibilities is to preserve the part of main memory that is occupied by the operating system itself — it cannot allow any part of it to be altered accidentally or intentionally.
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The processor manager decides how to allocate the central processing unit CPU and keep track of the status of each executable step of every program called a process or task. Later, when the process is finished, or the maximum amount of time has expired, the processor manager reclaims the processor so it can be allocated again. The device manager chooses the most efficient way to allocate all of the system's devices, including printers, disk drives, CD-ROMs compact disc -read only memory , keyboard, monitor, and so forth.
The device manager makes these decisions based on a scheduling policy chosen by the system's designers. The device manager allocates a device, starts its operation, and, finally, de-allocates it. The file manager keeps track of every piece of software in the system, including application programs, data files, directories, etc. The file manager allocates the file by opening it and de-allocates it by closing it. It is based on predetermined access policies to enforce the correct security for each file so that files can be accessed only by individual or group users that have permission to do so.
Operating systems with networking capability have a fifth element called the network manager, which provides a convenient way for users to share resources. Network resources usually include both hardware such as CPUs, memory areas, printers, disk drives, modems, and tape drives and software such as application programs and data files. Most modern operating systems feature a menu-driven graphical user interface GUI , which is pronounced "gooey," with menus, icons, and task bars. The Macintosh was the first widely used computer with a GUI, which in turn was based on a desktop created by Xerox.
Microsoft introduced Windows version 1. Microsoft's Windows 95, Windows 98, and Windows are true operating systems.
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- Operating system definition and examples of operating systems in use today.
- WHAT OPERATING SYSTEMS DO.
They accept commands that are typed into the system menus are not available. Command-driven systems are cumbersome for some new users to learn.
Gone but not forgotten: other Operating Systems
Therefore, since the lates, most operating systems including UNIX and Linux have been converted from command-driven to menu-driven interfaces, which feature GUIs that allow users to click on menus to make the system run. Adding GUIs was a popular move for anyone who had trouble working with brief or mysterious-looking command lines. Today, users can achieve a similar result by choosing an option from a menu. Linux is an operating system that has been widely adopted in commercial and academic markets around the world.
Linux is unique among the most-used operating systems because it is an open-source program, which means the source code is freely available to anyone for improvement. Programmers from around the world are encouraged to submit improvements to the programming code. If the new code is accepted as a universal improvement to the operating system, it is added to the next version, which is then made available to the computing world for further improvement.
This development technique has resulted in a powerful, stable, inexpensive operating system, which is constantly being improved by a variety of people who may never meet in person. Linux was created in Finland by year-old Linus Torvalds who wanted to build a new operating system for the Intel microprocessor.
Torvalds started with Minix, a miniature version of the well-known UNIX operating system, and rewrote certain parts to add more functionality.
It has been enhanced considerably in the years since. UNIX is a legal trademark, registered with the federal government. Before a developer can use the term UNIX to describe an operating system, it must demonstrate that it can meet certain certification criteria. One of the biggest differences among operating systems is the set of policies on which each one is based. These policies, in turn, drive design considerations, which dictate the inner workings of the system, including the following:. Before writing an operating system, these issues are examined by system designers who make choices that ideally will optimize the system's day-to-day operations.
The goal is to minimize downtime, system crashes, wasted overhead, security breeches, overloaded printers, and other operational problems. For example, if the designers want to create a simple operating system that would process each job in the order it arrives, without giving a higher priority to any of them, then the team might choose policies that would:. This would be a fair, unbiased system, but a very inefficient one. For example, if one big job was printing out thousands of pages for a large report, even if the printing required several days, then all other jobs would sit idle as they waited for it to finish.
In the meantime, most of the available memory space, processor time, disk space, and other resources would also sit idle, waiting for the next job to begin. Therefore, most modern operating systems feature complex formulas, which allow resources to be allocated wisely.
Some systems allow multiple tasks, multiple jobs, multiple users, and even multiple processors, to work together so available resources can be shared without causing the system to crash routinely. No single operating system can be considered the best for every situation because each one is based on policies that favor certain jobs or certain circumstances. That is why one operating system might be chosen to run an architect's computer and another might be preferred to operate a writer's computer.
Flynn, Ida M. Understanding Operating Systems, 3rd ed. DOS is the software that governs a computer's data storage and program execution. OS Abbrev. Os, symbol for the element osmium. An operating system is the software program that allows all the parts of a computer system to function. It controls everything from accepting input from a mouse or a keyboard to sending files to a printer.
Related currently there are three personal computer platforms pc mac and linux
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