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Articles by Bhanu Priya
Page 10 of 107
What are the Privileged and Non-Privileged instructions in Operating System?
In operating systems, instructions are classified into two main categories based on their access level and potential impact on system security and stability. Privileged instructions can only be executed in kernel mode, while non-privileged instructions can be executed in user mode. This classification ensures system protection and controlled access to critical resources. Privileged Instructions Privileged instructions are machine-level instructions that can only be executed when the processor is operating in kernel mode (also called privileged mode). These instructions have direct access to system resources and can potentially compromise system security if misused. Examples of Privileged Instructions ...
Read MoreWhat happens to a PCB when the state of a process changes?
Process Control Block (PCB) is a data structure used by the operating system to store essential information about each process. When a process changes state, the PCB is updated to reflect the new state and preserve the process's context for future execution. The PCB contains critical information that allows the OS to manage processes effectively during state transitions and context switches. PCB Components The important information stored in PCB includes the following − Process ID (PID) − Unique identifier for each process in the system. Process State − Current state (Ready, Running, Blocked, Terminated). Program ...
Read MoreWhat are a scheduler and a dispatcher in OS?
In operating systems, the scheduler and dispatcher work together to manage process execution. The scheduler decides which process should run next, while the dispatcher actually transfers control to the selected process. Understanding their roles is crucial for comprehending how an OS efficiently manages multiple processes. Scheduler A scheduler is a system component that selects processes from various queues and determines their execution order. Its primary function is to decide which process runs first based on specific scheduling algorithms and system policies. Types of Schedulers There are three different types of schedulers, each operating at different levels ...
Read MoreWhat is the computer structure?
Computer structure refers to the way components are arranged and interconnected to enable communication and data flow within a computer system. Understanding this structure is fundamental to grasping how computers process information and execute instructions. The basic computer structure can be visualized as interconnected components working together through various buses and communication pathways. Computer System Structure CPU ALU CU REG ...
Read MoreWhat is Process Suspension and Process Switching?
Process suspension and process switching are two fundamental concepts in operating system process management. Process suspension involves temporarily moving a process out of main memory, while process switching involves changing which process is currently executing on the CPU. Process Suspension Process suspension occurs when the operating system moves a process from main memory to secondary storage (disk) to free up memory space. When processes in main memory enter the blocked state, the OS may suspend one of them by transferring it to disk and bringing another process into memory. Most operating systems use additional suspended states beyond ...
Read MoreHow can kernels context-switch between processes?
Context switching is the process by which the kernel saves the state of a currently running process and loads the state of another process to give it CPU time. It's important to distinguish that a simple transition between user and kernel mode is not a context switch — a context switch specifically involves changing from one process to another. How Context Switching Works The kernel performs context switching through a series of coordinated steps to ensure process states are preserved and restored correctly: The values of the CPU registers are saved in the Process Control Block ...
Read MoreCompare and analyze any two major variations of message passing systems
Message passing systems enable processes to communicate by sending and receiving messages. Let us compare and analyze two major variations of message passing systems that demonstrate different architectural approaches and use cases. Client-Server Message Passing In client-server message passing, communication follows a request-response pattern where clients request services from servers. Consider an application reading data from a filesystem — the application acts as a client requesting data from a server. Server Process States The server process transitions through several states during message handling: Server Process State Transitions ...
Read MoreWhat resources are required to replace/modify at the core level of the operating system?
Operating System core modification refers to making fundamental changes to the kernel, system components, and underlying architecture. This requires extensive resources, expertise, and careful planning to ensure system stability and compatibility. Core Operating System Architecture Operating System Architecture Layers User Applications & Programs System Libraries & APIs Operating System Kernel (Process Management, Memory Management, Device Drivers) Hardware Abstraction Layer (HAL) ...
Read MoreWhat are the levels of computer system organization?
The computer system level hierarchy is a conceptual framework that describes different abstraction layers from the lowest hardware level to the highest user level. This hierarchy explains how computational activities are organized and how users interact with computer systems through various interfaces and abstraction layers. The computer system consists of seven distinct levels, each building upon the previous level to provide increasing abstraction and functionality. These levels bridge the gap between raw hardware and end-user applications. Levels of Computer System Organization Computer System Level Hierarchy ...
Read MoreWhat are interrupts and how interrupt handling is done in modern operating systems?
Interrupts are signals generated by hardware or software when a particular event requires immediate attention from the processor. These signals inform the CPU about high-priority, urgent information that demands interruption of the current working process to handle time-critical tasks. When an interrupt occurs, the processor completes the current instruction execution and transfers control to a special routine called an Interrupt Service Routine (ISR) or interrupt handler. This mechanism ensures that critical events are processed promptly without losing system responsiveness. Types of Interrupts Classification of Interrupts Interrupts ...
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