What is Computer virus

 

Virus -

Virus is defined as a program inserted into another program. It gets activated b it's host program. It replicated itself and spreads to other through floppy transfer. A virus infects data or program every time the user run the infected program and the virus takes advantages and replicated itself.

Two types of virus have been identified. They are 'Parasitic' and 'boot' virus.

Parasitic Virus -

This virus attaches itself to other program and is activated when the host program is executed. It tries to get attached to more programs so that chances of getting activated are more. It spreads o other computers when the affected program are copied.

Boot virus -

This virus is designed to enter the boot sector of a floppy disk or Hard disk. It works by replacing the first sector on the disc with part of itself.

It hides the rest of itself elsewhere on the disc, with a copy of first sector. The virus is loaded by the built in program when the machine is switched ON.

How Increases The Virus -

There is following reasons for Increases the virus:

1. Through floppy &CD

2. Through games

3. Through internet

4. Copying data from one PC to another

5. To use a virus infected program.

Some Hints -

Here are some hints to avoid virus infection in PC

1.  Never allow floppy discs brought from outside your company to be used directly on PC without checking floppy for virus presence. This includes service engineers and their floppy discs for maintenance

2.  Keep all original EXE and COM files in a write-protected floppy.

3.  If COM and EXE files are required to be copied anywhere, copy only from write protected original floppy.

4.  In case the system is 'hanging' the reason could be virus. Check for virus.

5.  Avoid playing computer games on a computer where important data is stored as it is generally noticed that virus spreads faster through game floppies.

6.  Check sector information as a routine by modifying AUTOEXEC.BAT and using virus check programs.

7.  If virus is found on a PC, isolate it, identify and remove the virus. Only then should the PC be put into use against.

Some Viruses -

C-Brain -

Amjed and Basit, two Pakistani brothers, developed this software in January 1986 to discourage people from buying illegal software at throwaway prices. This was the most famous virus ever found and has a record of damaging few millions gone personal computers. This is designed to stay in the boot sector in the disk or near zero sectors. The virus enters the machine once the PC is booted with the infected floppy.

Macmag -

This virus attacked apple Macintosh computer only. Not much damage is reported because of this virus. This was not noticed on any IBM PCs . It displayed a message of peace on the monitors and killed itself more data is not available on this virus.

Scores -

This virus also was found only on apple machintosh computer. This virus was first found in March 1987.