An operating system (OS) is system software. It is the manager of computer’s hardware and software resources and provides a basis for application program to execute. It acts as an intermediary between the computer user and hardware. OS provides basic functionality of managing the input and output devices, performing memory allocation and de-allocation and so on. Hence the OS creates an environment in which user can execute their programs conveniently and efficiently. Now days, OS is found on almost every device that contains computer for e.g. cellular phones, consoles, video games, super computers, web servers. Microsoft Windows is the most common OS, whereas Android, iOS, QNX are examples of modern operating systems.
Types of Operating Systems-
Types of Operating systems based on their Working Techniques-
Serial Processing-
It performs all the instructions into a sequence manner. In other words the instructions those are given by the user will be executed by using the first in first out (FIFO) manner. All the Instructions those are received first by the operating system will be executed first.
Batch Processing-
It is similar to the serial processing technique, but in batch processing similar types of jobs are firstly grouped and then submitted to the system for processing. The system then performs all the operations on the instructions one by one. During the batch processing the user can not be able to specify any input.
Multi Programming (executing many programs concurrently)-
Here the computer system can execute multiple programs at a time. In multi-programming the CPU will never get idle. A multiprogramming operating system can hold more than one program in memory at the same time. In case of multiprogramming, when a job/task cannot use the processor, the system can suspend, or interrupt, the job, freeing the processor to work on another job.
Real Time System-
In Real Time operating system the Response Time is already fixed. Means time to Display the Results after Possessing has fixed by the Processor or CPU. Real Time System is used at those Places in which we Requires higher and Timely Response. These Types of Systems are used in Reservation. So when we specify the Request, the CPU will perform at that Time.
Multi processing Operating System-
Generally a computer has a single processor means a computer have a just one processor for processing the instructions. But if we are running multiple jobs, then this will reduce the speed of the processing. For increasing the speed of processing then we uses the multiple processors in a single system. In multi processing there are two or more processors used in a single operating system.
Functions of OS-
• Processor management- It involves putting the tasks into order and pairing them into manageable size before they go to the CPU.
• Memory management- It coordinates data to and from RAM and determines the necessity for virtual memory.
• Device management- It provides interface between connected devices. Such as managing the various peripheral devices e.g. mouse, keyboard, etc.
• Storage management- It directs permanent data storage.
• Application allows standard communication between software and hardware.