Lesson 2: Virus Catagories
Boot Sector
Boot sector viruses infect the area of a disk that is used by the computer during boot up. Every disk, hard disk or floppy disk contains a small portion of that disk as a boot sector. Boot sector viruses write themselves to this portion of the disk and activates whenever a user tries to start up from the infected disk. Once activated the virus stays active in the memory infecting any disk read or written too, that is not write-protected, from the infected computer. This type of virus is dying out, as people become informed about it, and therefor more careful it becomes harder for virus programmers to write a virus that can outwit the informed user, so they switch to a different method. That being said, you should not let your guard down, there are still boot sector viruses out their, and if everyone ignored the threat than there would be a new influx of this type of virus. Boot sector viruses were almost all designed for DOS based systems, but this does not mean that other systems are not vulnerable. Every computer is vulnerable to boot sector viruses.
An example of a boot sector virus is the Stoned virus. Stoned was extremely widespread during the early 1990's, but has faded to near extinction. When a system is infected with stoned every so often when the computer boots up it will display the message "Your computer is now stoned." Generally speaking Stoned is an amusing virus with no real serious threat, however on 1.2M disks while writing to the boot sector the virus can "accidentally" cause damage.
