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Explain what is computer virus, types of virus

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The virus is the most harmful thing in Our Internet or Social Life. In this article, You will know about what a is computer virus, the Evolution of the virus, and different types of computer viruses and malware.

What is a Virus?


The virus is basically a small program. But the difference between the virus and any other program is that a virus manipulates and corrupts information. Once they are lodged, they control the activities of the host. This is possible because each strain of the virus contains within itself, all the information required to make perfect copies of it.

A computer virus is a software code that replicates itself. It spreads from program to program and from disk to disk, manipulating, and damaging valuable data. The major cause for concern is the spreading and damaging nature of viruses.

Most of the viruses are designed to perform simple feats, they do the following:

Corrupt the most sensitive area of the disk File Allocation Table (FAT) of the directory area. Modify the interrupt organization of the system; when a “read or write to screen operation” takes place, it is routed through the virus code in the memory resulting in interrupt clashes where a program opens up a file simultaneously for read-write access.

The virus interrupts every operation of the. Even though the virus may have instructions built into it to destroy data, it can nevertheless render a disk full of files absolutely useless.

Read More: Good and Bad Side of Internet

The Evolution of Virus:

The concept of virus dates back tO 1949 when John Von Neumann submitted a paper putting forward the concept of a self-replicating program. Subsequently, the first virus-like program appeared in the form of a recreational game called “CODE-WARS” at the Bell Labs of American Telephone and Telegraph Company.

In “Code-wars,” two players were told to code a set of programs that would destroy the programs of other players. Realizing the potential danger of such programs, the authors did not reveal the presence of such programs. Concurrently, at Massachu- setts Institute of Technology, students were carrying out experiments with the computer, which nobody had ever tried. Their relatively harmless hobby of messing up with other programs gave rise to the idea and concept of computer viruses.

The first commercial application of computer virus was in 1985 when two Pakistani brothers, in order to keep track of software piracy, used the Brain virus also known as the Pakistan virus on their low-cost software sold from their outlet in Lahore.

Classification of type of Computer viruses :

  • File viruses

File viruses, also known as parasitic or executable viruses, are pieces of code that attach themselves to executable files, driver files, and compressed files, and are activated when the host program is run. After activation, the virus may spread itself by attaching itself to other programs in the system. Most file viruses spread by loading themselves in system memory and looking for any other program locked on the drive.

Some Examples of file viruses are Randex, Meve, and MrKlunky.

  • Boot Sector Viruses

A boot sector virus affects the boot sector of the hard disk, which is a very crucial part. The boot sector is where all information about the drive is stored, along with a program that makes it possible for the Operating system to boot up. By inserting its code into the boot sector, a virus guarantees that it loads into memory during every boot sequence. A boot virus does not affect files; inserted, it affects the disks that contain them. Though boot viruses still exist, they are rare compared to new-age malicious software.

Some Examples of Boot Sector viruses are Polyboot, AnitiEXE.

Read More: The Main Difference Between HTTP and HTTPS

  • Multipartite Viruses

Multipartite Viruses are a combination of boot sector viruses and file viruses. These viruses come in through infected media and reside in memory. They then move on to the boot sector of the hard drive. From there, the virus infects executable files on the hard drive and spreads across the system. There aren’t too many multipartite viruses in existence today but in their heyday, they accounted for some major problems due to their capacity to combine different infection techniques.

An example of Boot Multipartite viruses is Ywinz.

  • Macro Viruses

Macro viruses infect files that are created using certain applications or programs that contain macros. These include Microsoft Office Documents such as Word, Excel, PowerPoint, Access database, and other similar application files such as Corel Draw, AmiPro, etc. Since macro viruses are written in all languages of the application, and not in that of the OS, they are known to be platform-independent-they can spread between windows, Mac, and any other OS, so long as they’re running the required application. The first macro virus was written for Microsoft word and it was discovered back in August 1995.

Some Examples of Macro viruses are Relax, Melissa. 

  • Network Viruses

This kind of virus is proficient in quickly spreading across a Local Area Network(LAN) or even over the internet. Usually, it propagates through shared resources, such as shared drives and folders. Once a new vulnerable system is found, the network virus infects the other system and thus spreads over the network.

Some Examples of Network viruses are Nimda and SQL Slammer.

  • E-mail Viruses

An e-mail virus could be a form of a macro virus that spreads itself to all the contacts located in the host’s email address book. If any of the e-mail recipients open the attachment of the infected mail, it spreads to the new host’s address book contacts and then proceeds to send itself to all those contacts as well. There are many ways in which a virus can infect document our PC. However, whether active or document, it’s dangerous to let loose on your system, and should be dealt with immediately.

Read More: What is Cyber Crime in Computer with Example

  • Trojan Horse

Trojan Horses are impostor files that claim to be something desirable but, in fact, are malicious. Rather than insert code into existing files, a Trojan horse appears to do one thing like install a screen sever or show a picture inside an e-mail. When in fact it does something entirely different, and potentially malicious, such as case files. Trojans can also open back so that computer hackers can gain access to passwords and other personal information stored on a computer.

Although often referred to as such, Trojan horses are not viruses in strict because they can not replicate automatically. For the Trojan horse to spread, it must be invited onto a computer by the user opening an email attachment or downloading and running a file from the Internet, for example.

  • Worm

A worm is a piece of software that uses computer networks and security flaws to create copies of itself. A copy of the worm will scan the network for any other machine that has a specific security flaw. It replicates itself to the new machine using the security flaw, and then being scanning and replicating a new worm.

Worms are programs that replicate themselves from system to system without the use of a host file. This is in contrast to viruses, which require the spreading of an infected host file. Although worms generally exist inside of other files, often Word or Excel documents, there is a difference between how worms and viruses use the host file. Usually, the worm will release a document that already has the “worm” macro inside the document. The entire document will travel from a computer virus to a computer, so the entire document should be considered the worm.

Examples of worms Viruses are Mydoom or ILOVEYOU 

  • Other malicious software

Earlier, the only way a computer was at risk was when you inserted an infected floppy. With the new age of technology, almost every computer is interconnected to the rest of the world at some point or the other, so it’s difficult to pinpoint the source and/or time of the infection. As if that weren’t bad enough, new-age computing has also brought about a new breed of malicious software. Today, the term ‘virus’ has become a generic term used for all the different ways that your computer can be attacked by malicious software. Besides the type of viruses, we mentioned here’s a look at some of the newer problems we face today.

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Explain How to Write Curve,bend and wrap text in ms word

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How Write Curve text in ms word
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Microsoft Word is one the most useful Software for office work, Student presentation, and many more. We use Curve, bend, and wrap text in ms word many times as an office, collage, School presentation Heading. In this article, You will know how to Write Curve, bend, and wrap text in ms word Step by step.

Why do we use Curve, bend, and wrap text in ms word?

Curved text is used when you design a flyer, newsletter, and logo in your Word document to enhance the look of the presentation. Microsoft Word has a very easy way to Write Curve, bend, and wrap text.

How to Write Curve, bend, and wrap text in MS Word Step by step:

Step 1: Open the new or an existing Word document.

Step 2: Highlight or select the text that you want to curve, bend, or warp.

Step 3: Go to the Insert tab on the Ribbon and click on the WordArt icon in the Text section.

Read Also: What is Mail Merge in MS word, How to use it

M S Word Step 1

Step 4: A list of WordArt will appear. Select the letter style from the WordArt list to apply to the text.

WordArt List

Step 5: Once WordArt is added to your text, a new menu Drawing tool is created automatically. Now, go to the Format tab on the Ribbon and click on the drop-down icon then click Text Efforts in the WordArt Styles section.

Text Effect in ms word

Step 6: Click on the Transform option from the Text Effects drop-down menu. Select the curve that you want to apply in the selected text.

How to Write Curve Text in ms word

Result: Now your Selected word is Transformed in your chosen style(Curve, bend, and wrap).

Carve text in Ms Word

 

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Explain Lookup function in Excel | Explain V and H lookup Function

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Explain Lookup function in Excel
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Lookup is one of the most used full functions in Microsoft Excel. It’s used to categorize under Excel Lookup and reference functions. In this article, I explain What is the Lookup function in Excel | Explain V and H lookup Function

Explain Lookup function in Excel

The LOOKUP Function is categorized under Excel Lookup and reference functions. This section discusses various techniques that you can use to look UP a value in a range of data Excel has three functions(LookUP, V LookUP, H LookUP) designed for this task.

A Look-UP formula essentially returns a value from a table by looking up another related value. A common telephone directory provides a good analogy. If you want to find a person’s telephone number, You first locate the name and then retrieve the corresponding number.

Example of LookUp Function in Excel :

In Worksheet that uses Several look UP formulas. This Worksheet Contains a table of employee data, beginning in row 7. This range name is EmpData. When you enter the last name into cell C2, lookup formulas in D2:G2 retrieve the matching information from the table. If the last name does not appear in column C, the formulas return.

Explain Lookup function in Excel

The following lookup formulas use the Vlookup function:

  • D2 = VLOOKUP (C2, EmpData,2,FALSE)
  • E2 = VLOOKUP (C2, EmpData,3,FALSE)
  • F2 = VLOOKUP (C2, EmpData,4,FALSE)
  • G2 = VLOOKUP (C2, EmpData,5,FALSE)

 

Explain V-Lookup Function in Excel


The VLookup function looks up the value in the first column of the lookup table and returns the corresponding value in a specified table column. So, the lookup table arranges vertically.

The syntax  for the VLookUp Function is: VLOOKUP(lookup_value,table_array,col_index_num,range_lookup)

The VLookup Function’s arguments are as follows:

  • lookup_value: The value is to be in the first column of the lookup table.
  • table_array: The range that contains the lookup table.
  • col_index_num: The column number within the table from which the matching value is in return.
  • range_lookup: Optional. If TRUE or omitted, an approximate match is returned. However, If FALSE, Vlookup will search for an exact match and, if Vlookup can’t find an exact match, the function returns #/NA.

Explain H-Lookup Function in Excel


The HLookup function works just like the VLookup function except that the lookup table is arranged horizontally instead of vertically. The HLookup function looks up the value in the first row of the lookup table and returns the corresponding value in a specified table row.

The syntax  for the HLookUp Function is: HLOOKUP(lookup_value,table_array,row_index_num,range_lookup)

The HLookup function’s arguments are as follows:

  • lookup_value: The value is to be in the first row of the lookup table.
  • table_array: The range that contains the lookup table.
  • row_index_num: The row number within the table from which the matching value is in return.
  • range_lookup: Optional. If TRUE or omitted, an approximate match is returned. However, If FALSE, Vlookup will search for an exact match and, if Vlookup can’t find an exact match, the function returns #/NA.

I hope you get the all information about Explain Lookup function. V and H lookup Function in Excel with Example. If you like this article, you can share and comment. So that we too have a chance to learn something from your ideas and improve something.

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Difference between Vector and Raster graphics?Example

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Difference between Vector and Raster graphics with Example
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Graphics help us to see the photo, video, Animation Popularly, and Vector Graphics are sharp and detailed than Raster Graphics. In this article, I Explain the Difference between Vector and Raster graphics with Examples.

What is the difference between Vector and Raster graphics?

Graphics are part of Multimedia. In Digital media like Photo, Video, Animation all these things are made by graphics. Graphics are two types Vector Graphics and Raster Graphics.

Vector Graphics

Raster Graphics

Vector Graphics are composed of paths. Raster graphics are composed of pixels.
Vector Graphics such as a.eps file or Adobe Illustrator file are composed of paths or lines, that are either straight or curved. Raster graphics Such as a .gif .jpeg is arranging of pixels of various colors, which together form an image.
The data file for a Vector image contains the points where the paths and ends how much the path curve, and the colors that either border or fill the paths. Raster graphics, on the other hand, become “blocky” since each pixel increases in size as the image is larger.
Vector Graphics is Capable of detailed editing. Raster graphics are Less detailed but offer precise paths.

Read Also: What is Multimedia in Computer With Example

Difference between Vector and Raster graphics with Example

Example of Vector Graphics Software with Format:

  1. Adobe Illustrator.
  2. CorelDraw.

Vector Graphics typically saved as EPS, AI, SVG, PDF Format.

Example of Raster graphics Software with Format:

  1. Adobe Photoshop.
  2. Gimp.

Raster Graphics saved as JPG, GIF, PNG, TIF, BMP Format.


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