CODING PUSH

Windows commonly used shortcut keys [Quick lookup dictionary version] 1. Lock account [Win+L]   Press [Win+L] to lock the user, leave temporarily (to fish in the toilet) and no longer be afraid of privacy leaks!  

 What are the different states of the process?  In the five-state model, there are 5 states in the process, which are created, ready, running, terminated, and blocked. The running state is that the process is running on the CPU. In a single-processor environment, at most one process is running at any time. The ready state means that the process is ready to run, that is, the process has obtained all the required resources except the CPU, and can run once it obtains the CPU. The blocking state is when the process is waiting for an event to suspend operation, such as waiting for a resource to be available or waiting for I/O to complete. Even if the CPU is idle, the process cannot run. Running state → blocking state: It is often caused by waiting for peripherals, waiting for resource allocation such as main memory, or waiting for manual intervention. Blocking state → Ready state: The waiting condition has been met, and it can run only after being allocated to the pro...

 What is the difference between concurrency and parallelism? Concurrency means that multiple tasks will be processed within a period of time; but at a certain moment, only one task is executing. Single-core processors can achieve concurrency. For example, there are two processes A and B. After A runs for a time slice, it switches to B, and B runs for a time slice and then switches to A. Because the switching speed is fast enough, the macroscopically shows that multiple programs can be run at the same time within a period of time. Parallel means that there are multiple tasks being executed at the same time. This requires a multi-core processor to complete, and multiple instructions can be executed at the same time at the microscopic level. Different programs are run on different processors. This is a physical process of multiple processes at the same time.   What is the difference between a large kernel and a micro kernel? The big kernel is to put all the functions of...

 What is a process? A process is a program being executed and is the basic unit of operating system resource allocation. Generally speaking, a process contains instructions, data, and PCB.   What is the difference between an orphan process and a zombie process? Orphan process means that a parent process exits while one or more of its child processes are still running, then these child processes will become orphan processes. The orphan process will be adopted by the init process (process with process ID 1), and the init process will complete the state collection work for them. Because the orphan process will be adopted by the init process, the orphan process will not cause harm to the system. A zombie process is a process descriptor of a child process that will not be released when the child process exits. It will only be released when the parent process obtains the child process information through wait() or waitpid(). If the child process exits and the parent proces...

 What is the purpose of the command interpreter? Why is it usually separate from the kernel? Would it be possible for the user to develop a new command interpreter using the system‐call interface provided by the operating system? Answer: It reads commands from the user or a file of commands and executes them, usually by turning them into one or more system calls. It is usually not part of the kernel since the command interpreter is subject to changes. A user should be able to develop a new command interpreter using the system‐call interface provided by the operating system. The command interpreter allows a user to create and manage processes and also determine ways by which they communicate (such as through pipes and files). As all of this functionality could be accessed by a user‐level program using the system calls, it should be possible for the user to develop a new command‐line interpreter. Why is the separation of mechanism and policy desirable in an operating system? Answer:...

 How do clustered systems differ from multiprocessor systems? What is required for two machines belonging to a cluster to cooperate to provide a highly available service? Answer: Clustered systems are typically constructed by combining multiple computers into a single system to perform a computational task distributed across the cluster. Multiprocessor systems on the other hand could be a single physical entity comprising of multiple CPUs. A clustered system is less tightly coupled than a multiprocessor system. Clustered systems communicate using messages, while processors in a multiprocessor system could communicate using shared memory. In order for two machines to provide a highly available service, the state on the two machines should be replicated and should be consistently updated. When one of the machines fails, the other could then take‐over the functionality of the failed machine. Some computer systems do not provide a privileged mode of operation in hardware. Is it possib...

Nowadays, USB disks are used more and more widely , not only can store and copy data, but also install systems, but various problems will also occur during use . USB disk poisoning is a more serious problem, so how to detect Is there a virus in USB disk? Let's take the Win7 flagship system as an example to tell you about it. How to quickly detect and judge whether the USB flash drive is infected Step by Step method: 　　1. The original folder stored in the USB disk suddenly disappeared. This may be caused by a pseudo-folder U disk virus. 　　2. Right-click the letter of the USB disk, and commands such as "AutoPlay", "Brower" or "Open" have been added to the menu. 　　3. All files in the USB disk have become .exe format files and cannot be opened normally . 　　4. After the USB disk is plugged into the computer, it will take a long time to be recognized by the win7 system computer . 　　5. When double-clicking the USB disk under win7 system, the USB ...

Recently, users of the win7 flagship system have reported that they usually open the game menu in the start menu to directly enter the game, but sometimes they do not see the game menu in the start menu . What's wrong? Here I will tell you how to solve the problem of adding a game menu to the download start menu of the win7 flagship version . Step by Step method: How to add a game menu to the start menu under Win7 Ultimate? 1. Open the start menu. There is no game function in the start menu of the editor. The editor below will add it to this panel to display, click Run at the bottom right of the start menu to open the running program; 2. Open the running program, and then enter: gpedit.msc in the input box behind the opening of the running program, and then click the OK button below or press Enter to execute gpedit.msc; 3. Execute the gpedit.msc program to open the local group policy editor, as shown in the figure below. In the list under the local computer policy on the left, ...

With the popularity of the Windows 7 system, more and more Windows XP users have switched to Windows 7 system, but because the new system is not familiar with the process of use, maybe due to many external reasons leading to failure and problems, resulting in the computer can not be used properly. Now the small editor will be the user reflects the situation more concentrated some of the problems sorted out, for your reference:  How to resolve "The upgrades program stopped at 62% " in Windows 7 Description: Upgrade issue for WIndows 7. Vista users found that after they chose to upgrade Windows 7, the upgrade stopped at 62%. You can open the installer log file to see where the problem is. Microsoft confirmed that this issue occurred as a result of the Iphlpsvc service stopping to respond during the upgrade process. Solution: 1) Restart your computer and go back to Windows Vista; 2) Click Start, right-click My Computer, and then click Properties; 3) On the Advanced tab, click En...

1 The concept and characteristics of cloud computing  1.1 What is the cloud  Cloud computing, a popular term in the IT industry in recent years, is not a new technology, but a fusion of multi-door IT technology. This article will briefly introduce the basic concepts and characteristics of cloud computing, explore why enterprises need cloud computing and the process of building cloud computing. 1.1 What is cloud computing? Cloud computing is an internet-related service growth, usage, and delivery model that provides dynamically scalable and virtualized resources over the Internet. Simply put, cloud computing, which utilizes the transmission capabilities of the Internet to transfer data storage and processing from local servers to the Internet, is not a new technology, but a product of the convergence of traditional IT technologies such as distributed computing, parallel computing, network storage, virtualization, and so on. Cloud computing is divided into narrow cloud computing...

Amazon, Microsoft, HP, Yahoo, Intel, IBM, and other companies have announced their own "cloud plan", cloud security, cloud storage, internal cloud, external cloud, public cloud, private cloud, so what is cloud computing technology? Where are the generations, concepts, principles, applications, and prospects for cloud computing technology ... In 2006, Google launched the "Google 101 Program" and formally introduced the concept and theory of "cloud". Then Amazon, Microsoft, HP, Yahoo, Intel, IBM, and other companies have announced their own "cloud plan", cloud security, cloud storage, internal cloud, external cloud, public cloud, private cloud ... A dizzying array of concepts is constantly hitting people's nerves. So what exactly is cloud computing technology? Where are the concepts, principles, applications, and prospects for cloud computing technology? First, the development of cloud computing ideas Under the traditional model, an enterprise ...