Parity virus

 Virus Information - Parity virus:

This virus infects the boot sector of floppy disks and the partition table (MBR) of the hard disks. The virus infects the computer when booted with an infected disk. The virus infects the hard disk the first time it infects the computer. When the virus is active in the memory, it will be infecting the boot sector of all the floppy disks if write protect notch is open. Since this is a stealth virus, changes made to floppy will not be noticed when it is in memory.