A virus is a self replicating program that can destroy or cause damage to data stored on a computer system.
A virus program must be executed in order to infect a computer system. Viruses can attach themselves to other programs in order to ensure that this happens. Viruses are spread through file downloads or infected storage media such as floppy disks.
Common symptoms of virus infection:
Delivery is the method by which the virus arrives on the computer. The main vectors are boot sector, email, IM, network or infected file.
The virus may be deliberately introduced to the computer or the infection may be accidental.
Floppy disks and hard disks store a small program known as the boot record which is run when the computer starts up. Boot sector viruses attach themselves to this program and execute when the computer tries to start up from the infected disk. Once a computer has been infected, any unprotected floppy disk put into the computer will also be infected.
A virus checker or Anti-Virus Software will scan files and check for traces of a virus and is then able to remove the virus.
Anti-virus software works in two modes: stand-alone and memory resident. In stand-alone mode the software works like any other program. You start it and point it at a file, directory or disk to check the files for viruses.
In memory-resident mode the anti-virus software stays running on your system at all times. Whenever a file is used the software will check it for viruses. As well as checking files, most anti-virus software will also check e-mails and web pages.
Have a think about this virus, how do the virus actions of replication, camouflage, watching & delivery apply?
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