Unit 4 Business on the Internet

These days you can conduct business without in reality handing goods or cash. But e-commerce is much more that merely a substitute for traditional shopping. E-commerce operates from business to consumer and business to business. Business-to-business e-commerce goes further and includes electronic data exchange or interchange (EDI), a speedy, automated system of information exchange between companies who work closely together. Another example is standardization of specifications within a given field, for ease of price calculations in a competitive market. E-commerce is an ideal medium. Sending data over a network is more efficient and much faster than "traditional" methods and thus, far more cost effective. E-business is really nothing more than using the Internet and its related technologies to conduct normal business operations. Whether in advertising, sales, purchasing, human resources, marketing or management, the Internet can be used to increase productivity, reduce costs and thus increase turnover. In other words it's a management, tool. And what's more, it's a management tool that is accessible to all businesses, whether a one-man-operation or a large corporation.

Unit 5 Text c Laptops Power Supply

Power Supply like desktops, Laptops can be plugged into the wall to receive AC power from the electric power grid through an AC adapter. But what makes the laptop unique is that it is portable; so, laptops are also powered by batteries. All laptops use some type of rechargeable battery (lithium, nickel-cadmium, nickel-metal hydride).

The battery life varies depending on the type of rechargeable battery (lithium batteries tend to hold their charge longer) and how you use your computer (frequent use of disk drives consumes a lot of battery power). In addition to the main battery, laptops have other batteries to run clocks and backup CMOS RAM.

Unit 6 Text c Computer Infections

A virus is a small piece of software mat instil on real programs. For example, a virus might attach itself to a program such as a spreadsheet program. Each time the spreadsheet program runs, the virus runs, too, and it has the chance to reproduce (by attaching to other programs) or wreak havoc. E-mail viruses - An e-mail virus moves around in e-mail messages, and usually replicates itself by automatically mailing itself to dozens of people in the victim's e-mail address book. A worm is a small piece of software that uses computer networks and security holes to replicate itself. A copy of the worm scans the network for another machine that has a specific security hole. It copies itself to the new machine using the security hole, and then starts replicating from there, as well. Trojan horses - A Trojan horse is simply a computer program that claims to do one thing (it may claim to be a game) but instead does damage when you run it (it may erase your hard disk). Trojan horses have no way to replicate automatically.

Computer viruses are called viruses because they share some of the traits of biological viruses. A biological virus is not a living thing, so it has no way to do anything or to reproduce by itself.