Before working on the difference between all three schedulers, let us recall the concept of process scheduler.Process scheduler is a part of the Operating system which schedules the process. If the process is in ready, waiting and running state it schedules it correctly and is also responsible for the allocation of the CPU processor to a specific task within a time interval.Also, when the task or process is completed it doesn't allow the CPU to sit idle. It will allocate the other task depending on its current state. If the process was in ready state it will allocate it to ... Read More

The processes that are entering into the system are stored in the Job Queue. Suppose if the processes are in the Ready state are generally placed in the Ready Queue.The processes waiting for a device are placed in Device Queues. There are unique device queues which are available for every I/O device.First place a new process in the Ready queue and then it waits in the ready queue till it is selected for execution.Once the process is assigned to the CPU and is executing, any one of the following events occur −The process issue an I/O request, and then placed ... Read More

A thread is a small unit of CPU utilisation. It comprises a thread ID, a program counter, a register set and a stack. It shares with other threads which belong to the same process having code segment, data section and other operating system resources like open files and signals.A heavy weight process has a single thread of control. If a process has multiple threads of control, it can perform more than one task at a time. Many software packages that run in modern PC’s are multi-threaded. Here, the application is implemented as a separate process with several threads of control.For ... Read More

Micro kernel is one of the classifications of kernel and is often represented as μ- kernel. It is software which provides a mechanism to implement an operating system.The functions or mechanism for implementation are as follows −Inter-process communicationThread managementLow level address space managementIn the micro kernel, user services and kernel services are kept in different address spaces. User services are placed in user address space. Kernel services are placed in kernel services. Therefore, the size of the kernel and size of the operating system is minimized or reduced.Given below is the diagram of micro kernel −It is very secure and ... Read More

Computer architecture can be defined as a set of rules and methods that describe the functionality, management and implementation of computers. To be precise, it is nothing but rules by which a system performs and operates.Sub-divisionsComputer Architecture can be divided into mainly three categories, which are as follows −Instruction set Architecture or ISA − Whenever an instruction is given to processor, its role is to read and act accordingly. It allocates memory to instructions and also acts upon memory address mode (Direct Addressing mode or Indirect Addressing mode).Micro Architecture − It describes how a particular processor will handle and implement ... Read More

Process scheduler assigns different processes to CPU based on particular scheduling algorithms.Types of Process Scheduling AlgorithmsThe different types of process scheduling algorithms are as follows −FCFSAs the name goes, jobs are executed on a first come first serve basis. It’s a simple algorithm based on FIFO that's first in first out. It is pre-emptive and non pre-emptive and its performance is poor based on its average waiting time.SJFIt is also known as the shortest job first or shortest job next. It is a pre-emptive and non pre-emptive type algorithm that is easy to implement in batch systems and is best ... Read More

Process scheduler is a part of the Operating system which schedules the process. If the process is in ready, waiting and running state it schedules it correctly and is also responsible for the allocation of the CPU processor to a specific task within a time interval.Also, when the task or process is completed it doesn't allow the CPU to sit idle. It will allocate the other task depending on its current state. If the process was in ready state it will allocate it to the CPU in this way it always keeps the CPU busy all of the time.Characteristics of ... Read More

We can discuss some of the issues to consider in designing multithreaded programs. These issued are as follows −The fork() and exec() system callsThe fork() is used to create a duplicate process. The meaning of the fork() and exec() system calls change in a multithreaded program.If one thread in a program which calls fork(), does the new process duplicate all threads, or is the new process single-threaded? If we take, some UNIX systems have chosen to have two versions of fork(), one that duplicates all threads and another that duplicates only the thread that invoked the fork() system call.If a ... Read More

Distributed Operating System is a type of model where applications are running on multiple computers linked by communications. It is an extension of the network operating system which supports higher levels of communication and integration of the machines on the network.Distributed OS runs on multiple CPUs but for an end-user, it is just an ordinary centralized operating system. It can share all resources like CPU, disk, network interface, nodes, computers, etc. from one site to another site, and it increases the data available on the entire system.All processors are connected by valid communication media such as high-speed buses and telephone ... Read More

A thread is a lightweight of process and is a basic unit of CPU utilization which consists of a program counter, a stack, and a set of registers.Given below is the structure of thread in a process −A process has a single thread of control where one program can counter and one sequence of instructions is carried out at any given time. Dividing an application or a program into multiple sequential threads that run in quasi-parallel, the programming model becomes simpler.Thread has the ability to share an address space and all of its data among themselves. This ability is essential ... Read More