We discuss some operating systems which is mainly used.
Time Sharing Systems : Time Sharing System or Multi-tasking is a logical extension of multi-programming. So this system is also called Multi-tasking systems. Here jobs are executed by the CPU switching between them. The CPU scheduler a job from the ready queue and switches the CPU to that job. When time slot expired, the CPU switches from this job to another. In this system , the CPU time shared by different processes. So,it is said to be ” Time Sharing Systems”.
Parallel Systems : Most of computers having only one CPU. However, there is a tread towards Multi-Processor systems, such systems have more than one processor in close communication, sharing the computer bus,the clock, and some times memory and peripheral devices, these systems are referred as ” Tightly Coupled Systems”. This system consisting of more than one processor and it is a tightly coupled that is called parallel system. In Parallel Systems, number of processors executing their jobs parallel. There are several reasons for buildings such systems.
Distributed Systems : In Distributed Systems, the processors can’t share the memory and clock, processor has its own local memory. The processor communicate with one another through various communication lines. Such as high speed buses, these systems are usually referred to as “Loosely coupled Systems”.
Real-time Embedded System : These systems are designed for one or few application. Best examples for real-time embedded systems are fire sensors, smoke sensors etc.