The Operating System
The Operating System
The operating system, abbreviated OS, is the set of programs a central computing device that interfaces between hardware and application software.
Intermediate between software applications and hardware, operating system serves three distinct intentions: the operating system allows the use of hardware devices which coordinates and optimizes the use, it provides software application programming interfaces standard that simplify the use of material and finally realizing various functions to ensure reliability (fault tolerance, fault isolation) and security (traceability, confidentiality, integrity and availability).
An operating system can be used to coordinate the use of or processor (s) and allow some time for the execution of each process, to reserve space in memory for program needs and to organize the contents of hard drives or other mass storage into files and directories. It can also be used to create the digital image that contains the human-machine interfaces of various programs and send it to monitor and receive operations performed by the user via the keyboard, mouse or other peripherals and forward them to different programs.
Operating systems are often sold with computing devices. Various software tools are provided with the operating system. They allow the user to adjust the configuration settings of the operating system, or perform the basic operations to manipulate files.
The first operating systems were created in the 1960s. In 2010 the two families of operating systems are the most popular Unix (including Mac OS X and Linux) and Windows, the Windows family has a near monopoly on personal computers, with more than 90% market share for 15 years, while the market share of Unix operating systems are nearly 50% on servers.
Operating System Types
An operating system is designed to work with a specific range of machines (processor type, manufacturer, architecture). If an operating system is available for many different machines ranges, then the same source code is compiled [note 1] and adapted to each machine range. The exact list of machines on which it can be used also depends on the range of drivers included in the operating system.
According to its construction, an operating system can be multi-tasking or so single-task, multi-user or single user, so it can be multi-processor and / or real time.
* An operating system is called multi-tasking when it allows the simultaneous execution of several programs. The leading operating system multitasking appeared in the 1960s, and all operating systems today are multi-tasking.
* It is said multi-user when it is designed to be used simultaneously by many users, often via a computer network. Such operating systems are typically used for servers and mainframes or supercomputers. They are multi-tasking and generally secure, that is to say he will refuse to execute any transaction for which the user has not previously received permission.
* It is said multi-processor when it is designed to operate a computer with multiple processors. In such operating systems, several programs are executed simultaneously by different processors.
* It is said real time as it ensures that transactions are conducted in strict deadlines, and that whatever the conditions of use. Such operating systems are used in industry, aerospace or consumer electronics to create real-time systems.
For example OS / 2 operating system is a multi-tasking single-user personal computers compatible PC architecture, so that the Solaris operating system is a multi-tasking, multi-user and multi-processor for stations work, servers and supercomputers built by Sun Microsystems.
To be continued…
Study: From Wikipedia, the free encyclopedia. The text is available under the Creative Commons.
