In this tutorial, you will learn how to install VirtualBox on Debian 11 desktop version. VirtualBox is a general-purpose full virtualizer for x86 hardware, targeted at server, desktop and embedded use.
This blog post explores how to use VirtualBox and contains the following sections:
How to set up VirtualBox? Enabling CPU virtualization feature Downloading the VirtualBox installer Running the installer and defining the installation options Deploying a new VM Creating a virtual machine Installing a guest OS Shared folders and clipboard Making a VM copy Using snapshots How to use VirtualBox for recording video inside the VM
A computer can address more memory than the amount physically installed on the system. This extra memory is actually called virtual memory and it is a section of a hard disk that’s set up to emulate the computer’s RAM.
National Cyber Security Awareness by FBI, In today’s digital world, online safety should be of paramount concern for all individuals and organizations because the threats posed by cyber criminals can’t be ignored. And to counteract these threats, there are steps you can take to minimize the risks associated with doing any kind of business online, surfing the Internet, and/or sharing information on social media sites.
Malware, short for “malicious software,” refers to any intrusive software developed by cybercriminals (often called “hackers”) to steal data and damage or destroy computers and computer systems. Examples of common malware include viruses, worms, Trojan viruses, spyware, adware, and ransomware. Recent malware attacks have exfiltrated data in mass amounts.
Whether you run a business or go online for yourself, you probably know that browsing the web can open you and your organization up to all sorts of risks. By connecting to the internet, you expose yourself and your business to hackers and thieves, who could steal anything from personal information and web browsing history to payment data. So, when it comes to protecting yourself and your business online, you may have looked into private browsing or choosing a VPN. But which of these is right for you?
This course is for total Beginners, you will learn how to code using the C Programming Language in an easy, simple, and efficient way.
Whether you are an experienced programmer or not, this website is intended for everyone who wishes to learn the C programming language. There is no need to download anything - Just click on the chapter you wish to begin from, and follow the instructions.
In this post we are taking a look at some commands that can be used to check up the partitions on your system. The commands would check what partitions there are on each disk and other details like the total size, used up space and file system etc. Commands like fdisk, sfdisk and cfdisk are general partitioning tools that can not only display the partition information, but also modify them.
Tarballs provide a versatile way to back up and manage groups of files on Linux systems. Follow these tips to learn how to create them, as well as extract and remove individual files from them.
Partitioning a disk can make it easier to organize files, such as video and photo libraries, especially if you have a large hard drive. Creating a separate partition for your system files (the startup disk) can also help protect system data from corruption since each partition has its own file system.
A Network File System or NFS is necessary for helping your business share files over a network. An NFS is a protocol that lets users on client computers access files on a network. You can access remote data and files from anything that links to the network you will use. All people within a network will have access to the same files, making file-sharing efforts easier.
Like any other operating system, GNU/Linux has implemented memory management efficiently and even more than that. But if any process is eating away your memory and you want to clear it, Linux provides a way to flush or clear ram cache.
inux is an awesome operating system. It performs good with fewer resources and tries to maximize utilization of available resources automatically and because of this, it’s slightly difficult to understand resource utilization.
ometimes, we might need to check for total memory size on a server running Linux or we might need to use memory stats in shell scripts. Fortunately, we have access to numerous tools that we can use to check for total physical memory. In this tutorial, we’re going to take different approaches to serve that purpose by using several useful commands and tools.
At times we will need to know precisely how our Linux systems use memory. This article will examine how to use the free command-line utility to view memory usage on a Linux system. In doing so, we will clearly define the difference between free vs. available memory on Linux systems.
In C, learning pointers is simple and enjoyable. Certain Programming language activities are easier to complete with pointers, while others, like dynamic memory allocation, seem impossible to complete without them. To be a competent C developer, it is thus beneficial to understand pointers. Within C, a pointer is a variable that holds the location of some other variable.
You probably know that operating systems deal with addresses when storing values, just as you would label things inside a warehouse so you have an easy way of finding them when needed. On the other hand, an array can be defined as a collection of items identified by indexes. You will see later why pointers and arrays are usually presented together, and how to become efficient in C using them.
Computers store data in memory in binary. One thing that is often overlooked is the formatting at the byte level of this data. This is called endianness and it refers to the ordering of the bytes. Specifically, little-endian is when the least significant bytes are stored before the more significant bytes, and big-endian is when the most significant bytes are stored before the less significant bytes.
Memory is one of the most important host resources. For workloads to access global system memory, we need to make sure virtual memory addresses are mapped to the physical addresses. There are several components working together to perform these translations as efficient as possible. This blog post will cover the basics on how virtual memory addresses are translated.
Demand paging is a process of swapping in the Virtual Memory system. In this process, all data is not moved from hard drive to main memory because while using this demand paging, when some programs are getting demand then data will be transferred.
Physical addresses are provided by the hardware, Virtual (or logical) addresses are provided by the OS kernel. OS divides physical memory into partitions. Different partitions can have different sizes
Virtual memory is a feature of an operating system that enables a computer to be able to compensate shortages of physical memory by transferring pages of data from random access memory to disk storage. This process is done temporarily and is designed to work as a combination of RAM and space on the hard disk. This means that when RAM runs low, virtual memory can move data from it to a space called a paging file. This process allows for RAM to be freed up so that a computer can complete the task.
According to an old rule of thumb, your page file or swap should be “double your RAM” or “1.5x your RAM.” But do you really need a 32 GB page file or swap if you have 16 GB of RAM?. You probably don’t need that much page file or swap space, which is a relief considering a modern computer might have a solid-state drive with very little space.
As you learn what a sawp file is and does, you will learn how to create and activate one on your Linux instance. Armed with this knowledge, you will be able to ensure that your system will no longer run out of memory.
This lesson will introduce you to the concept of page replacement, which is used in memory management. You will understand the definition, need and various algorithms related to page replacement. A computer system has a limited amount of memory. Adding more memory physically is very costly. Therefore most modern computers use a combination of both hardware and software to allow the computer to address more memory than the amount physically present on the system. This extra memory is actually called Virtual Memory.
System call fork() is used to create processes. It takes no arguments and returns a process ID. The purpose of fork() is to create a new process, which becomes the child process of the caller. After a new child process is created, both processes will execute the next instruction following the fork() system call. Therefore, we have to distinguish the parent from the child.
A thread is a single sequential flow of execution of tasks of a process so it is also known as thread of execution or thread of control. There is a way of thread execution inside the process of any operating system. Apart from this, there can be more than one thread inside a process. Each thread of the same process makes use of a separate program counter and a stack of activation records and control blocks. Thread is often referred to as a lightweight process.
You are already aware of the term multitasking that allows processes to run concurrently. Similarly, multithreading allows sub-processes (threads) to run concurrently or parallelly. Also, we can say that when multiple threads run concurrently it is known as multithreading. Some widely used programming languages like Java and Python allow developers to work on threads in their program. In this blog, we will learn what are the various multithreading models and the benefits of multithreading in OS. So, let’s get started.
The exec family of system calls replaces the program executed by a process. When a process calls exec, all code (text) and data in the process is lost and replaced with the executable of the new program. Although all data is replaced, all open file descriptors remains open after calling exec unless explicitly set to close-on-exec. In the below diagram a process is executing Program 1. The program calls exec to replace the program executed by the process to Program 2.
This web explain about USING MAKEFILES AND THE SECOND-STAGE BOOTLOADER.
Semaphore is simply a variable that is non-negative and shared between threads. A semaphore is a signaling mechanism, and a thread that is waiting on a semaphore can be signaled by another thread. It uses two atomic operations, 1)wait, and 2) signal for the process synchronization.
Deadlock is a situation that occurs in OS when any process enters a waiting state because another waiting process is holding the demanded resource. Deadlock is a common problem in multi-processing where several processes share a specific type of mutually exclusive resource known as a soft lock or software.
Starvation is the problem that occurs when low priority processes get jammed for an unspecified time as the high priority processes keep executing. A steady stream of higher-priority methods will stop a low-priority process from ever obtaining the processor. Starvation happens if a method is indefinitely delayed. This can emerge once a method needs a further resource for execution that isn’t assigned.
Deadlock and starvation are conditions in which the processes requesting a resource have been delayed for a long time. However, deadlock and starvation are not the same things in many ways. Deadlock happens when every process holds a resource and waits for another process to hold another resource. In contrast, in starvation, the processes with high priorities continuously consume resources, preventing low priority processes from acquiring resources. In this article, you will learn the difference between deadlock and starvation. But before discussing the difference between deadlock and starvation, you must need to learn about deadlock and starvation.
In this tutorial, we will be covering the concept of Process synchronization in an Operating System.
Process Synchronization was introduced to handle problems that arose while multiple process executions.
Process is categorized into two types on the basis of synchronization, Independent Process and Cooperative Process.
Peterson’s algorithm (or Peterson’s solution) is a concurrent programming algorithm for mutual exclusion that allows two or more processes to share a single-use resource without conflict, using only shared memory for communication. It was formulated by Gary L. Peterson in 1981.[1] While Peterson’s original formulation worked with only two processes, the algorithm can be generalized for more than two.
Critical Section is the part of a program which tries to access shared resources. That resource may be any resource in a computer like a memory location, Data structure, CPU or any IO device. The critical section cannot be executed by more than one process at the same time; operating system faces the difficulties in allowing and disallowing the processes from entering the critical section. The critical section problem is used to design a set of protocols which can ensure that the Race condition among the processes will never arise. In order to synchronize the cooperative processes, our main task is to solve the critical section problem. We need to provide a solution in such a way that the following conditions can be satisfied.
The process scheduling is the activity of the process manager that handles the removal of the running process from the CPU and the selection of another process on the basis of a particular strategy.
Process scheduling is an essential part of a Multiprogramming operating systems. Such operating systems allow more than one process to be loaded into the executable memory at a time and the loaded process shares the CPU using time multiplexing.
A Process Scheduler schedules different processes to be assigned to the CPU based on particular scheduling algorithms. There are six popular process scheduling algorithms which we are going to discuss in this chapter −
First-Come, First-Served (FCFS) Scheduling Shortest-Job-Next (SJN) Scheduling Priority Scheduling Shortest Remaining Time Round Robin(RR) Scheduling Multiple-Level Queues Scheduling
In the Operating System, the process scheduling algorithms can be divided into two broad categories i.e. Preemptive Scheduling and Non-Preemptive Scheduling. In this blog, we will learn the difference between these two.
In this article, we will have an in-depth discussion about Big O notation. We will start with an example algorithm to open up our understanding. Then, we will go into the mathematics a little bit to have a formal understanding. After that we will go over some common variations of Big O notation. In the end, we will discuss some of the limitations of Big O in a practical scenario. A table of contents can be found below.
When a process is first created by the OS, it initializes the program control block for the process and the new process enters the system in Not-running state. After some time, the currently running process will be interrupted by some events, and the OS will move the currently running process from Running state to Not-running state. The dispatcher then selects one process from Not-running processes and moves the process to the Running state for execution.
Multiple processor scheduling or multiprocessor scheduling focuses on designing the system’s scheduling function, which consists of more than one processor. Multiple CPUs share the load (load sharing) in multiprocessor scheduling so that various processes run simultaneously. In general, multiprocessor scheduling is complex as compared to single processor scheduling. In the multiprocessor scheduling, there are many processors, and they are identical, and we can run any process at any time.
The multiple CPUs in the system are in close communication, which shares a common bus, memory, and other peripheral devices. So we can say that the system is tightly coupled. These systems are used when we want to process a bulk amount of data, and these systems are mainly used in satellite, weather forecasting, etc.