23. Cable Modem. 1124

Cable modems provide bi-directional data communication via radio frequency channels. They are used to deliver broadband Internet access in the form of cable Internet.

Hybrid Networks developed, demonstrated and patented the first high-speed, asymmetrical cable modem system in 1990.

Hybrid Networks offer highly asymmetrical communications sufficient to satisfy consumers, connected remotely to an otherwise completely symmetric high-speed data communications network.

It’s very expensive to provide high speed in the upstream direction, while the CATV (Cable TV) systems have substantial broadband capacity in the downstream direction. Different communications media use different protocols working in each direction to establish a closed loop communications system.

The speeds and protocols used in each direction are very different. The earliest systems used the public switched telephone network (PSTN) for the return path since very few cable systems were bi-directional.

Later systems used CATV for the upstream as well as the downstream path. Hybrid's system architecture is used for most cable modem systems today.

24. Limitations of Mobile Internet. 1243

Though the access to the Internet "on the go" has many advantages, such as the ability to communicate by e-mail and obtain information anywhere, the Web, accessed from mobile devices, has a large number of limitation, which may vary, depending on the device.

Small screen size makes it difficult or impossible to see text and graphics clearly. Only one page at a time can be displayed on the screen. So, multi-tasking and easy revert to a previous page are impossible.

In most mobile devices the flexibility in navigation is limited. They use touch panels or touch pads instead of a mouselike pointer. Moving a finger along the surface of the touch pad is transformed into the cursor movement across the screen.

Many sites cannot be accessed on a mobile device. Although recently this has been changing.

Most mobile devices, have a very slow speed, often slower than dial-up Internet access.

On many devices a single page is broken into segments, which are each treated as a separate page. Many pages, in their conversion to mobile format, are compressed. Navigation between these pages is slow.

However, the latest smartphones such as the IPhone and those using the Android operating system overcome some of these restrictions.

25. Will the computers think instead of us? 1110

Is it easy to think? – Not always. What do we mean by thinking? Can computers think?

Thinking means handling of information, computing, reasoning it. The word “computer” comes from a Latin word meaning “to count”. In fact, a computer was designed as a special kind of counting machine.

In the Middle Ages there were few books, and it was easy for a man to handle nearly all the information they contained.

In the age of global “computerization” a computer is not only a calculating machine. It stores and analyses information, it functions as your personal librarian, controls your budget or diet, plays several hundreds games, etc.

In new Millennium knowledge accepted by mankind is stored in computers and made accessible to anyone with a home computer.

Computers will not replace man’s creative abilities, they will expand them. They solve our problems in all the brunches of our life.

The application of electronics allows to have the content of books, magazines and articles fed into the computer memory, where it is analyzed, arranged in a certain order and produced on request as a printed computer program.