TYPES OF OPERATING SYSTEM http://www.tutorialspoint.com/operating_system/os_types.htm Copyright © tutorialspoint.com

Operating systems are there from the very first computer generation. Operating systems keep evolving over the period of time. Following are few of the important types of operating system which are most commonly used.

Batch operating system
The users of batch operating system do not interact with the computer directly. Each user prepares his job on an off-line device like punch cards and submits it to the computer operator. To speed up processing, jobs with similar needs are batched together and run as a group. Thus, the programmers left their programs with the operator. The operator then sorts programs into batches with similar requirements. The problems with Batch Systems are following. Lack of interaction between the user and job. CPU is often idle, because the speeds of the mechanical I/O devices is slower than CPU. Difficult to provide the desired priority.

Time-sharing operating systems
Time sharing is a technique which enables many people, located at various terminals, to use a particular computer system at the same time. Time-sharing or multitasking is a logical extension of multiprogramming. Processor's time which is shared among multiple users simultaneously is termed as time-sharing. The main difference between Multiprogrammed Batch Systems and Time-Sharing Systems is that in case of Multiprogrammed batch systems, objective is to maximize processor use, whereas in Time-Sharing Systems objective is to minimize response time. Multiple jobs are executed by the CPU by switching between them, but the switches occur so frequently. Thus, the user can receives an immediate response. For example, in a transaction processing, processor execute each user program in a short burst or quantum of computation. That is if n users are present, each user can get time quantum. When the user submits the command, the response time is in few seconds at most. Operating system uses CPU scheduling and multiprogramming to provide each user with a small portion of a time. Computer systems that were designed primarily as batch systems have been modified to time-sharing systems. Advantages of Timesharing operating systems are following Provide advantage of quick response. Avoids duplication of software. Reduces CPU idle time. Disadvantages of Timesharing operating systems are following. Problem of reliability. Question of security and integrity of user programs and data. Problem of data communication.

Distributed operating System
Distributed systems use multiple central processors to serve multiple real time application and multiple users. Data

Distributed systems use multiple central processors to serve multiple real time application and multiple users. Data processing jobs are distributed among the processors accordingly to which one can perform each job most efficiently. The processors communicate with one another through various communication lines (such as high-speed buses or telephone lines). These are referred as loosely coupled systems or distributed systems. Processors in a distributed system may vary in size and function. These processors are referred as sites, nodes, computers and so on. The advantages of distributed systems are following. With resource sharing facility user at one site may be able to use the resources available at another. Speedup the exchange of data with one another via electronic mail. If one site fails in a distributed system, the remaining sites can potentially continue operating. Better service to the customers. Reduction of the load on the host computer. Reduction of delays in data processing.

Network operating System
Network Operating System runs on a server and and provides server the capability to manage data, users, groups, security, applications, and other networking functions. The primary purpose of the network operating system is to allow shared file and printer access among