How viruses steal email addresses?

Generally, when a HTML page is opened the Internet browser saves a copy of the page on the hard drive, in order to get back the data soon if the user wishes to read it again. If the computer is infected with virus, then the virus analyses the saved HTML pages and selects any e-mail addresses it finds.

It also extracts addresses from Outlook contacts and from various other documents stored on hard drive. Some new viruses have the ability to bind common names to standard domains like .aol, .msn, .yahoo and also the common extensions used by many antivirus vendors.

In this way e-mail addresses are guessed and the virus gets transmitted. It also attempts to use e-mail address as the sender's return address to harm others. Some viruses created by hackers not only steals email addresses but also passwords.
If the computer is infected with virus and the user visits an infected page, the virus checks the computer for FTP programs which has username and password and then sends them to hackers server.

Types of Barcode Readers

A barcode reader or barcode scanner is an electronic device used for scanning or reading printed barcodes. It takes the data from the barcode and sends it into a computer system and then information is converted.

Fundamentally, there are five types of barcode readers.

• A Pen type reader is a simple barcode reader familiar for its durability and low cost and does not involve any moving parts. It reads the barcode by remaining in direct contact with the bar code at a fixed angle.
• A Slot Scanner is a stationary device and the item with the bar code on it is pulled or dragged by hand through the slot. Slot scanners are mainly used to scan bar codes on identification cards.
• A CCD Scanner is generally used in retail sales and has a better reading range than the pen reader. A difficulty with the CCD scanner is, it cannot read a bar code that is more than its input.
• An Image Scanner, also known as Camera reader, uses a small video camera to capture the image of the bar code and then uses modern digital image processing techniques to read or decode the bar code.
• A Laser Scanner can be hand-held or stationary, and can easily read the bar code from 24 inches away.
• A laser scanning can finish 500 scans per second and reduces the occurrence of errors.