Education Operating System

OPERATING SYSTEM An operating system is a set of software that manage computer hardware resources and provides common services for computer programs .the operating system is a vital component of the system software in the computer system .application programs require an operating system to function. Time-sharing operating systems schedule tasks for efficient use of the system and may also include accounting 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 act as an intermediate between programs and comp. h/w although the application code is usually executed directly by the h/w and will frequently make a system call to an OS function or be interrupted by it. operating system can be found on almost on any device that contain a comp. -from cellular phones and video game consoles to supercomputers and web servers. Examples of popular modem operating systems include Andriod,BSD,iOS,Linux,Mac OS X,Microsoft Windows, Windows Phone , and IBM z/OS. All these , except Windows and z/OS , share roots in UNIX. Various types of Operating systems are as follows: Real-time: 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 behavior. 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. Multi-user A multi -user operating system allows 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. Being able to use multiple accounts on a Windows operating system does not make it a multi-user system. Rather, only the network administrator is the real user. But for a UNIX-like operating system, it is possible for two users to login at a time and this capability of the OS makes it a multi -user operating system. Multi-tasking vs. Single-tasking When only a single program is allowed to run at a time, the system is grouped under a single-tasking system. However, when the operating system allows the execution of multiple tasks at one time, it is classified as a multi -tasking operating system. Multi -tasking can be of two types: pre -emptive or co-operative. In pre -emptive multitasking, the operating system slices the CPU time and dedicates one slot to each of the programs. Unix-like operating systems such as Solaris and Linux support pre-emptive multitasking, as does amigaOS. Cooperative multitasking is achieved by relying on each process to give time to the other processes in a defined manner. versions of Microsoft Windows used cooperative multi-tasking.versions, both Windows NT and Win9x, used pre-emptive multi-tasking. Mac OS prior to OS X used to support cooperative multitasking. An operating system, abbreviated OS, is a product, software type,  that is part of a system, equipment or computerized equipment, which deals with management and coordination of its activities. The computerized system may be a computer, a workstation, a server, a PC, a notebook, a smartphone, a road navigation device or another system with "intelligence" of its own. The operating system plays the role of host for all applications running on the equipment (hardware). Operating system functions To act as interface between hardware and users, an operating system must be able perform the following functions: 1. Enabling startup application programs. Thus, the operating system must have: - A text editor - A translator - An editor of links 2. The allocation of resources needed to execute programs is done by identifying: the programs that are running, the need for memory, peripheral devices and data protection requirements. 3. Facilities for data compression, sorting, mixing, cataloging and maintenance of libraries, through utility programs available. 4. Plan implementation works according to certain criteria, for efficient use of central processing units. 5. Assisting implementation of programs through computer-user communication system, at both hardware and software level.