Against computer viruses

Computer viruses are the main hazards:

1. Data on the computer viruses stimulate the direct destructive effect
Most of the virus in direct damage to the computer when excited by important information data, the use of the means are formatted disk, overwrite the file allocation table and directory area, delete important files or with meaningless "junk" data overwrite files, damaged CMO5 set and so on. Disk killer virus (D1SK KILLER), contains the counter, after exposure in the hard drive within 48 hours of total boot time excited, excited, when displayed on the screen "Warning!! Don'tturn off power or remove diskette while Disk Killer is Prosessing!" (Warning! D1SK KILLER ll1 at work, do not turn off power or remove the disk), rewrite the hard drive data. Was D1SK KILLER damaged hard drive antivirus software can repair, do not give up easily.

2. Take up disk space and the destruction of information
Parasitic virus on the disk to the illegal occupation of part of the total disk space. Boot virus is by the way the general occupation of occupied disk boot sector virus itself, but the original boot sector to other sectors, that is to guide virus to overwrite a disk sector. Be covered by the permanent sector data loss, can not be recovered. File type virus infection by using some DOS functions, these DOS features can detect unused disk space and transmission parts of the virus writes to the disk of unused parts. So in the course of infection usually does not destroy the original data on disk, but the illegal occupation of the disk space. Some file-type virus quickly, in a short time a large number of infected files, each file is lengthened to different degrees, it causes a serious waste of disk space.

3. Occupy system resources
In addition VIENNA, CASPER and a few other viruses, the other most of the virus are under the permanent in the dynamic memory, which must occupy a part of system resources. The basic memory occupied by the virus compared with the virus itself the length of a considerable length. Viruses occupy memory, resulting in reduced memory, part of the software can not run. In addition to occupying the memory, the virus also seize the interrupt, system operation. Many computer operating system function is called by interrupt technique to achieve. In order to stimulate virus infection, always amend the relevant interrupt address, interrupt the normal process of accession to the virus "stuff" to interfere with the normal operation of the system.

4. Affect the computer speed
After the virus entered the memory not only interfere with system operation, but also affect the computer speed, mainly:
(1) virus infection to determine excitation conditions, the total work to the state of the computer monitor, which compared with the normal operation of the computer state is superfluous and is detrimental.
(2) Some viruses to protect themselves, not only the static virus, disk encryption, and the presence of dynamic memory, the virus also at the encryption status, CPU time when addressing the virus to run for some office decryption program to decrypt the encrypted virus CPU instructions into a legitimate re-implementation; the end of the virus to run a program then re-encrypt the virus. This extra CPU as well as on the implementation of thousands of million instructions.
(3) transmission of the virus during the same time to insert additional illegal operation, particularly when infected floppy disk is not only significantly slows down the computer speed and disk read and write the normal order is disrupted, a cacophony of noise.

5. Computer Virus error and unforeseen hazards
Computer viruses and other computer software, a major difference is that the virus was no accountability. The preparation of a comprehensive computer software requires a lot of manpower, material, perfect after a long debugging, software can be introduced. However, neither virus producers seem necessary to do so, it is impossible to do so. Many computer viruses are isolated in the preparation of a computer on the hastily thrown out after debugging. Anti-virus experts of a large number of viruses found in the vast majority of viruses are varying degrees of error. Another major source of error is the virus variants of the virus. Some novice computer who does not have the ability to independently develop software, out of curiosity or other reasons
Modify other viruses, causing an error. Computer viruses are often the consequences of the error is not predictable, anti-virus workers has been detailed in the black friday presence of the virus nine errors, ping-pong virus has five errors. But people can not spend a lot of time to analyze the error of tens of thousands of viruses. Large spread of the virus with unknown error propagation, the consequences are difficult to predict.

6. Compatibility of computer viruses affecting the system operation
Compatibility is an important indicator of computer software, compatibility, good software can be run in a variety of computer environments, whereas poor compatibility of the software is on the operating conditions "cherry-picking" model and operating system version, etc. required. The preparation of the virus are generally not in a variety of computer environments to test the virus, so the compatibility of the virus less often lead to crashes.

7. Computer viruses to users serious psychological stress
According to statistics on computer sales, computer users suspected of sale, "the computer has a virus" and an advisory service about 60% of the workload. The detection of the existence of the virus and about 70%, while only 30% of cases of suspected users, but in fact the computer and no virus. Then the user suspect the reason the virus is it? Mostly occur such as computer crashes, software run abnormal phenomenon. These phenomena do is probably caused by computer viruses. But not all, in fact, the computer work "exception" when is very difficult for an ordinary user to accurately determine whether the virus is. Most users prefer to believe the virus to take some attitude, which is undoubtedly for the protection of computer security is very necessary, but often have to spend time, money and so on price. Merely suspected of virus, the temerity to format the disk caused by the loss even more difficult to remedy. Not only individual stand-alone users, in some large-scale network systems are not immune to the virus and stop the screening. In short computer viruses like "ghost" as shrouded in the minds of the general computer user and have caused tremendous psychological pressure, which greatly affected the efficiency in the use of modern computer, and the resulting loss is immeasurable intangible.

Computer virus on the computer system could make a great impact. Most of the viruses are the computer programs and data destruction. The following describes the destruction of the virus and the impact of different manufacturers.
Some computer viruses such as FormatC (macro virus) and Stoned Daniela, when they are triggered when the hard disk unconditional format and delete all the system files on disk. To AOL4Free Trojan Horse as an example, it is attached to the e-mail message and with the AOL4FREE.COM a file name. In fact, it is DOS utility (utility) - BATEXEC 1.5 version of the batch file (batch file) conversion over the 〔This utility is used to convert into a number of large batch file to go faster〕.
The Trojan Horse in the first difference in the DOS directory to find DELTREE.EXE this file, and then use this file to the hard drive to delete all the files inside. When a file is deleted, it will display a DOS error message: "BadCommand or file 〃 obscene name and a message (obscene message). DELTREE.EXE if the virus can not find it, it can not delete the file, but the obscene message (obscene message) will appear.
Some viruses, such as the Monkey (Stoned. Empire. Monkey) and AntiEXE, infects the Master Boot Record (Master Boot Record MBR) and DOS boot sector (Dos Boot Sector), after that it will reduce the memory and hard disk performance, up to When our computer screen displayed when the number of messages or other damage.
To AntiEXE as an example, in the boot process to load the master boot record (MBR), the virus has not infected this will be stored in the hard disk MBR column (Cylinder) O, side (Side) O, sector (Sector ) 13 position. and then the virus will it in the virus code on the MBR and the MBR has been written in the infected hard disk column (Cylinder) O, side (Side) O, Sector (Sector) 1 position . When AntiEXE virus active in memory when it will get read by any drive to the toxic MBR and \ or DBS re-introduced the same area a clean (clean counterpart). as when the disk read process the MBR and \ or DBS placement, the virus will look for *. EXE files for a particular (its identity has still not know), and then file damage.
Another example, One Half will about half of the hard drive is encrypted, and will display a message: Disk is one half. Press any key to continue. 〃 If we use the general to remove the MBR of the virus, all The data in the password area will be lost.
Feelings:
I think a lot of computer users, computer virus 』『 hear when they hear the mere mention of narcotics. Some of them, or indeed who have been victims, but more because of exaggerated hearsay Erzhi feel insecure. Not only fear, more of a wallet damage (businessman trap).

The dangers of computer viruses is well known, ranging impact machine speed, and at the destruction of documents or cause crashes. To facilitate the computer at any time for maintenance and maintenance, must be prepared to tools, such as clean dos boot disk or a windows98 boot disk, and kill the virus and disk tools, to meet the system could not start virus or hard drive and so on. Should also prepare a variety of accessories for drivers, such as optical drive, sound card, video card, modem, etc.. Floppy and CD-ROM cleaning disk and cleaning solution should also be standing.