Computer Virus

I am certain we all have heard of computer viruses and what they do. Now what really is a virus? A Virus is written software that is attached to a legitimate program with the intention of infecting other programs. It can attack either the computer’s systems entirely or the computer programs. People who have a thorough knowledge of how computer systems work and also know programming deliberately create these virus programs. Viruses are written in special programming languages or codes. This requires a high level of technical skill and knowledge. • The computer virus reproduces itself, as does a normal disease virus • It infects other programs • It can delete files/documents TYPES OF VIRUS 1. The Bomb: where the time of attack is activated at the specific date or time 2. The Trojan horse: the Trojan horse is disguised in computer programs that seem legitimate, such as computer games or interesting programs. A Trojan horse cannot replicate itself. It strikes immediately and is harmful to the system. 3. The Worm: it functions independently of other programs; it propagates itself through the system memory and gradually occupies more and more memory. The computer will progressively slow down until it stops completely. CLASSIFICATION OF VIRUSES 1. Boot Sector virus: insinuates itself onto the boot sector of a diskette or hard disk. Every time the computer is switched on and copies of itself onto the hard drive, and onto every diskette. 2. File virus: manifests itself in the system memory and resides there until a certain program has then been activated. The program will be infected HOW TO DETECT A VIRUS 1. Unusual system activity: • A file copied message appears on the screen without the user having invoked a copy command. • Unexplained disk drive activity occurs, for example the diskette drive’s light switches on indicating that date is being read from or written to the drive, when no read-write instructions/commands are given • The system behaves slowly and strangely 2. Change to diskette or hard disk structures. • Bad clusters appear on a diskette or hard disk. • Volume labels are altered • The number of files on a diskette increases, when no additional files have been created. 3. Change to executable programs • The size of an executable program suddenly increases • The creation date of a file inexplicably changes • Programs take appreciably longer than normal to load • Programs or commands take longer than normal to execute. • Program or date files are corrupted. HOW TO PROTECT YOUR COMPUTERS FROM VIRUSES 1. Avoid sharing diskettes on computers, accept no foreign diskettes in your computer 2. Protect all diskettes before uses if possible. Diskettes have write-protect switches 3. The difference in file capacity must be checked after disk copying. 4. Make regular backups from the hard disks and diskettes and keep them in a safe place. 5. Check all software for viruses before installation on the hard disk especially that of games. SOME ANTIVIRUS PROGRAMS A range of antivirus software is available to identify and clear viruses. These programs are constantly revised to keep up with the latest viruses. • Norton Antivirus • McAfee Antivirus • Kaspersky Antivirus • Doctor Solomon’s Antivirus • AVAST antivirus •