What are the dangers of computer viruses?

The harm of computer viruses is manifested by affecting the execution of programs and destroying user data and programs. The specific main harms are: 1. The virus triggers direct damage to computer data and information; 2. Occupies disk space and damages computer data. Destruction of information; 3. Seizing system resources; 4. Affecting computer running speed; 5. Computer virus errors and unforeseen harm; 6. The compatibility of computer viruses affects system operation, often causing crashes; 7. Computer viruses cause Causes severe psychological stress to users.

The operating environment of this article: Windows 7 system, Dell G3 computer.

The harm of computer viruses is manifested in affecting the execution of programs and destroying user data and programs.

The main hazards of computer viruses are:

1. Viruses cause direct damage to computer data and information

Most viruses directly destroy important computer information when they are activated. The methods used include formatting the disk, rewriting the file allocation table and directory area, and deleting important information. files or overwrite files with meaningless "junk" data, destroy CMO5 settings, etc. Disk Killer Virus (D1SK KILLER) contains a counter and is activated within 48 hours of boot time after the hard disk is infected. When activated, the screen displays "Warning!! Don'tturn off power or remove diskette while Disk Killer is Prosessing!" (Warning! D1SK KILLER ll1 is working, do not turn off the power or remove the disk), rewrite the hard disk data. The hard drive damaged by D1SK KILLER can be repaired with anti-virus software, so don’t give up easily.

2. Occupying disk space and damaging information

Viruses parasitic on the disk will always illegally occupy part of the disk space. The general invasion method of boot viruses is that the virus itself occupies the boot sector of the disk and transfers the original boot sector to other sectors, that is, the boot virus overwrites one disk sector. The overwritten sector data is permanently lost and cannot be recovered. File-type viruses use some DOS functions to infect. These DOS functions can detect unused space on the disk and write the infected part of the virus to the unused parts of the disk. Therefore, the original data on the disk is generally not destroyed during the infection process, but the disk space is illegally occupied. Some file-type viruses infect very quickly, infecting a large number of files in a short period of time, and each file is lengthened to varying degrees, causing a serious waste of disk space.

3． Seize system resources

Except for a few viruses such as VIENNA and CASPER, most other viruses are resident in memory under dynamic conditions, which will inevitably seize some system resources. The basic memory length occupied by the virus is roughly the same as the length of the virus itself. The virus seizes memory, causing the memory to be reduced and some software to be unable to run. In addition to occupying memory, viruses also seize interrupts and interfere with system operation. Many functions of the computer operating system are implemented through interrupt calling technology. In order to cause infection, viruses always modify some relevant interrupt addresses and add the virus' "private goods" during the normal interrupt process, thus interfering with the normal operation of the system.

4. Affecting the computer's running speed

After the virus enters the memory, it not only interferes with the system operation, but also affects the computer speed. The main manifestations are:

(1) In order to determine the infection triggering conditions, the virus always affects the work of the computer. status, which is redundant and harmful relative to the normal operating state of the computer.

(2) In order to protect themselves, some viruses not only encrypt the static viruses on the disk, but also encrypt the dynamic viruses after entering the memory. The CPU must run a decryption process every time it addresses the virus. The program decrypts the encrypted virus into legal CPU instructions and then executes it; when the virus is finished running, a program is used to re-encrypt the virus. In this way, the CPU executes thousands or even tens of thousands of additional instructions.

(3) The virus also inserts illegal additional operations when infecting. Especially when infecting a floppy disk, not only the computer speed is significantly slowed down, but the normal reading and writing order of the floppy disk is disrupted, making a harsh noise.

5. Computer virus errors and unforeseen harm

One major difference between computer viruses and other computer software is the irresponsibility of viruses. Compiling a complete computer software requires a lot of manpower and material resources. After a long period of debugging and improvement, the software can be launched. But in the opinion of virus compilers, this is neither necessary nor possible. Many computer viruses are hurriedly programmed and debugged by individuals on a computer and then thrown out. After analyzing a large number of viruses, anti-virus experts have found that most viruses have varying degrees of errors.

Another major source of erroneous viruses is variant viruses. Some computer beginners who do not have the ability to independently compile software modify other people's viruses out of curiosity or other reasons, causing errors.

The consequences of computer virus errors are often unpredictable. Anti-virus workers once pointed out in detail that there were 9 errors in the Black Friday virus and 5 errors in the Ping Pong virus. But it is impossible for people to spend a lot of time analyzing the errors of tens of thousands of viruses. A large number of viruses containing unknown errors spread, and the consequences are unpredictable.

6. The impact of computer virus compatibility on system operation

Compatibility is an important indicator of computer software. Software with good compatibility can run in various computer environments. On the contrary, software with poor compatibility is "picky" about operating conditions, such as machine model and operating system version. Virus compilers generally do not test viruses in various computer environments, so viruses have poor compatibility and often lead to crashes.

7． Computer viruses cause serious psychological pressure to users

According to statistics from relevant computer sales departments, consultations made by computer after-sales users who suspect "the computer has a virus" account for more than 60% of the after-sales service workload. About 70% of the cases are confirmed to have viruses, and the other 30% are just suspected by users, but in fact there is no virus on the computer. So what are the reasons why users suspect viruses? Most of the time, phenomena such as computer crashes and abnormal software operation occur. These phenomena are indeed likely to be caused by computer viruses. But not entirely. In fact, when the computer is working "abnormally", it is difficult to ask an ordinary user to accurately judge whether it is caused by a virus.

Most users adopt an attitude of trusting viruses. This is undoubtedly necessary to protect computer security, but it often costs time, money, etc. The damage caused by rashly formatting the disk simply because of suspicion of a virus is even more difficult to make up for. Not only individual stand-alone users, but also some large-scale network systems will inevitably have to shut down to detect

viruses. In short, computer viruses hang over the minds of computer users like "ghosts", causing huge psychological pressure on people and greatly affecting the efficiency of modern computers. The intangible losses caused by this are inestimable.

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