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JSS3: COMPUTER STUDIES - 1ST TERM

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  1. Computer Career Oppurtunities | Week 1
    5Topics
    |
    1 Quiz
  2. Computer Viruses I | Week 2
    7Topics
    |
    1 Quiz
  3. Computer Viruses II | Week 3
    7Topics
    |
    1 Quiz
  4. Introduction To The Internet | Week 4
    4Topics
    |
    1 Quiz
  5. Internet Terminologies | Week 5
    4Topics
    |
    1 Quiz
  6. The Concept of Digital Divide | Week 6
    5Topics
    |
    1 Quiz
  7. Database Concept, Definition And Terminologies | Week 7
    4Topics
    |
    1 Quiz
  8. Database II | Week 8
    4Topics
    |
    1 Quiz
  9. Database III | Week 9
    13Topics
    |
    1 Quiz
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The Oxford English dictionary defines a virus, as a small living thing that causes infectious illnesses. For instance, HIV/AIDs Virus.

However, in computers, a virus is an undesired piece of code, that infects a system with the intention of making them malfunction, or not even function at all. Viruses cannot just arise spontaneously. It is man-made.

Computer viruses are small software programs, that are designed to spread, from one computer to another, and to interfere with computer operation. A computer virus might corrupt or delete data on your computer, use your email program to spread itself to other computers, or even erase everything on your hard disk.

Computer viruses are often spread by attachments in email messages or instant messaging messages. That is why it is essential, that you never open email attachments, unless you know who it is from, and you are expecting it.

Computer viruses also spread through downloads on the Internet. Most computer viruses have irritating damage, although there are some that are not all that harmful, these types can be transferred from computer to computer, through Removable disks. Examples are typo virus which affects keystrokes, Italian virus which produces a single character bouncing ball across the screen, the Dbase virus corrupts data to an unimaginable degree, La-Avenger virus affects files as they are opened and closed.

Before computer networks became widespread, most viruses spread on removable media particularly floppy disks. In the early days of the personal computer, many users regularly exchanged information and programs on floppies.

Some viruses spread by infecting programs stored on these disks, while others installed themselves into the disk boot sector, ensuring that they would be run when the user wants to boot the computer from the disk, usually inadvertently. Personal computers, of the era, would attempt to boot first, from a floppy, if one had been left in the drive.

Until floppy disks fell out of use, this was the most successful infection strategy, and boot sector viruses were the most common category of computer viruses. Traditional computer viruses emerged in the 1980s, driven by the spread of personal computers, and the resultant increase in modem use and software sharing.

Types of Computer Viruses:

There are two major types of Computer Viruses;

1. Boot Sector virus.

2. Executable file virus.

We will discuss both in the coming topics.

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