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This article will explain in detail what are the harmful manifestations of computer viruses. The editor thinks it is very practical, so I share it for you as a reference. I hope you can get something after reading this article.

The harm of computer virus is shown as affecting the execution of programs and destroying user data and programs. Its specific main hazards are: 1, virus stimulation of the direct destruction of computer data and information; 2, occupation of disk space and destruction of information; 3, preemption of system resources; 4, impact on computer running speed; 5, computer virus errors and unforeseen harm, and so on.

The harmfulness of computer viruses is shown in affecting the execution of programs and destroying user data and programs.

The main hazards of computer viruses are:

1. The direct destructive effect of virus stimulation on computer data and information

When activated, most viruses directly destroy the important information and data of the computer, such as formatting the disk, rewriting the file allocation table and directory area, deleting important files or rewriting files with meaningless "junk" data, destroying CMO5 settings, and so on. Disk killer virus (D1SK KILLER), which contains a counter, fires within 48 hours of the cumulative boot time after the hard disk is infected, and displays "warning! Don'tturn off power or remove diskette while Disk Killer is Prosessing!" on the screen when activated. (warning! D1SK KILLER ll1 is working, do not turn off the power or remove the disk), rewrite the hard disk data. Hard drives damaged by D1SK KILLER can be repaired with antivirus software, so don't give up easily.

2. Occupation of disk space and destruction of information

Viruses parasitic on disk always illegally occupy part of the disk space. The general encroachment mode of the bootstrap virus is that the virus itself occupies the disk boot sector and transfers the original boot area to other sectors, that is, the bootstrap virus has to cover a disk sector. The overwritten sector data is permanently lost and cannot be recovered. The file virus is infected by some DOS functions, which can detect the unused space of the disk and write the infected part of the virus to the unused part of the disk. Therefore, in the process of infection, the original data on the disk is generally not destroyed, but the disk space is illegally occupied. Some file-based viruses spread very fast, infecting a large number of files in a short period of time, and each file is lengthened to varying degrees, resulting in a serious waste of disk space.

3. Preempt system resources

Except for a few viruses such as VIENNA and CASPER, most of the other viruses are resident in memory dynamically, which is bound to seize part of the system resources. The basic length of memory occupied by the virus is roughly the same as the length of the virus itself. The virus grabs memory, resulting in a reduction in memory and a portion of the software cannot be run. In addition to occupying memory, the virus also preempts interrupts and interferes with the operation of the system. Many functions of computer operating system are realized by interrupt calling technology. In order to stimulate infection, the virus always modifies some relevant interrupt addresses and adds "private goods" of the virus in the normal interruption process, thus interfering with the normal operation of the system.

4. Affect the running speed of the computer

After entering the memory, the virus not only interferes with the operation of the system, but also affects the speed of the computer, mainly as follows:

The main results are as follows: (1) in order to judge the infection excitation conditions, the virus always monitors the working state of the computer, which is both superfluous and harmful relative to the normal running state of the computer.

(2) in order to protect themselves, some viruses not only encrypt the static virus on the disk, but also encrypt the dynamic virus after entering memory. Every time CPU addresses to the virus, it runs a decryption program to decrypt the encrypted virus into legal CPU instructions and then executes it; and when the virus runs, it uses a section of program to re-encrypt the virus. In this way, CPU executes thousands or even tens of thousands of additional instructions.

(3) when the virus is infected, it is also necessary to insert illegal extra operations, especially when infecting the floppy disk, not only the speed of the computer slows down obviously, but also the normal reading and writing order of the floppy disk is disturbed, making a harsh noise.

5. Computer virus errors and unforeseen harm

A big difference between computer viruses and other computer software is the irresponsibility of viruses. It takes a lot of manpower and material resources to compile a perfect computer software. After a long time of debugging and improvement, the software can be launched. But in the eyes of virus writers, it is neither necessary nor possible to do so. Many computer viruses are thrown out by individuals after being hastily compiled and debugged on a computer. After analyzing a large number of viruses, antivirus experts found that the vast majority of viruses have varying degrees of errors.

Another major source of error viruses is variants. Some beginners do not have the ability to write software independently and modify other people's viruses out of curiosity or other reasons, resulting in errors.

The consequences of computer virus errors are often unforeseeable. Anti-virus workers have pointed out in detail that there are 9 errors in Black Friday virus and 5 errors in ping-pong virus. But people can't spend a lot of time analyzing the mistakes of tens of thousands of viruses. A large number of viruses containing unknown errors spread, and the consequences are unpredictable.

6. Influence of compatibility of computer virus on system operation

Compatibility is an important indicator of computer software. software with good compatibility can be run in a variety of computer environments, while software with poor compatibility is "picky" to the operating conditions, requiring models and operating system versions. Virus programmers generally do not test viruses in a variety of computer environments, so the compatibility of viruses is poor, often resulting in

Crash.

7. Computer viruses cause serious psychological pressure on users.

According to the statistics of the relevant computer sales department, after-sales computer users suspect that "the computer has a virus" and put forward consultation accounts for more than 60% of the after-sales service workload. About 70% of the people tested that there is a virus, and another 30% of the cases are only suspected by the user, but in fact, the computer does not have a virus. So what is the reason for users to suspect the virus? Most of them are caused by phenomena such as computer crashing, abnormal software operation and so on. It is indeed possible that these phenomena are caused by computer viruses. But not all, in fact, when the computer is working "abnormal", it is difficult to ask an ordinary user to accurately judge whether it is caused by a virus.

Most users take a trustworthy attitude to the virus, which is undoubtedly necessary to protect computer security, but often have to pay the price of time, money and so on. It is even more difficult to make up for the loss caused by rashly formatting the disk just by suspecting the virus. It is not only for individual stand-alone users, but also for discrimination in some large network systems.

The machine stopped because of the virus. In short, like a "ghost", computer viruses hang over the minds of computer users, causing tremendous psychological pressure on people and greatly affecting the efficiency of the use of modern computers, and the resulting intangible losses are incalculable.

This is the end of the article on "what are the harmful manifestations of computer viruses". I hope the above content can be of some help to you, so that you can learn more knowledge. if you think the article is good, please share it for more people to see.

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