Operating System

The part of the process, where the code for accessing the shared resources is written, that part or section is the critical section (CS) of that process. Now the critical section problem is to implement such a solution, which can be used by the processes to cooperate when they share common resources. To execute its critical section, a process must take care of the three … [Read more...] about Critical Section Problem

Parallel processing requires multiple processors and all the processor works simultaneously in the system. Here, the task is divided into subparts and these subparts are then distributed among the available processors in the system. Parallel processing completes the job on the shortest possible time. Let us understand the scenario with the help of a real-life … [Read more...] about Parallel Processing

Contiguous memory allocation is a memory allocation method that allocates a single contiguous section of memory to a process or a file. This method takes into account the size of the file or a process and also estimates the maximum size, up to what the file or process can grow? Taking into account the future growth of the file and its request for memory, the operating system … [Read more...] about Contiguous Memory Allocation

Swapping is one of the several methods of memory management. In swapping an idle or a blocked process in the main memory is swapped out to the backing store (disk) and the process that is ready for execution in the disk, is swapped in main memory for execution. We will be discussing swapping in more detail. As we all know, a process must be placed in main memory for its … [Read more...] about Swapping in Operating System

Memory allocation is an action of assigning the physical or the virtual memory address space to a process (its instructions and data). The two fundamental methods of memory allocation are static and dynamic memory allocation. Static memory allocation method assigns the memory to a process, before its execution. On the other hand, the dynamic memory allocation method assigns … [Read more...] about Memory Allocation

Several users create thousands and millions of files in a file system. To organize these files properly file system uses directory structure. The directory structure has the entries of the all the files related to that directory. We can consider that a directory is a file, that contains information about the other files. Here, we will discuss some common schemes defining the … [Read more...] about Directory Structure

For each process, the operating system maintains the data structure, which keeps the complete information about that process. This record or data structure is called Process Control Block (PCB). Whenever a user creates a process, the operating system creates the corresponding PCB for that process. These PCBs of the processes are stored in the memory that is reserved for the … [Read more...] about Process Control Block (PCB)

Multithreading Models in Operating System exhibit the ways of mapping the user threads to the kernel threads. Here, we will learn about the three multithreading models, Many to One model, One to One model and Many to Many model. Many to One multithreading model maps many user threads to only one kernel thread. One to One multithreading model maps a single user thread to a … [Read more...] about Multithreading Models in Operating System

Shared memory system is one of the fundamental models of interprocess communication. In the shared memory system, the cooperating processes communicate with each other by establishing the shared memory region, in its address space. Shared memory model allows the fastest interprocess communication. Among the cooperating processes, the process that wants to initiate the … [Read more...] about Shared Memory System in IPC

First Come First Serve (FCFS) is the simplest CPU scheduling algorithm where the process that arrives first in the ready queue will be serviced first by CPU. Secondly, the FCFS is a non-preemptive scheduling algorithm in which once the process is allotted the CPU cycles it releases CPU when the process terminates or if it requests I/O. We can understand it with an example, … [Read more...] about First Come First Serve (FCFS) Scheduling Algorithm