Networks & Communications
After completing this section you should be able to:
- understand that information systems can be linked together on a world-wide scale
- explain the terms real-time processing, and batch processing
This video explains more about networking
An information system allows communication between a human user, the devices that make up the hardware of the system, and the software that performs systems functions and user applications. Data is entered into the system and information is gained as output.
Communication also takes place on a much wider scale.
Telecommunications and networks link computers of all kinds all over the world. It is becoming more and more common for people to work from a home base, electronically linked to world-wide communications systems.
Some people use the word ‘telecommute’ to describe working at a job from a home office with the aid of a computer, Internet link, telephone, fax and other specialised electronic equipment. Remember ICT refers to more than just computers. Fax machines, TV, the Internet and mobile phones are all part of ICT.
A travel agency provides a good example of the use of telecommunications with computers to provide customer services. The agency uses an on-line enquiry and booking system where a terminal in the agency office is connected to the main processor via a telecommunications link. The terminal can be either a dumb terminal, which is simply a screen and a keyboard, or a smart terminal, which is a screen, keyboard and processor with some backing store. The telecommunications link can be a telephone line, microwave link or radio link.
Exam questions sometimes ask you to describe how ICT has led to more people working from home. Try to use the correct terms.
The system is likely to be interactive. This means that when a travel agency employee wants to access the system, he or she will start by entering data (perhaps the agency’s official reference number) on an opening screen. You may be required to describe a computer system in use. Each time the employee enters an item or items of data on a particular screen, the system will reply with further screens and prompts for more data until an outcome is obtained.
In effect, the computer system has a conversation with the travel agency employee in order to achieve a particular task such as booking an airline ticket for a passenger. Many airline and other travel tickets are now electronic. No printed ticket is issued at all. For example, the traveller is told when to travel by information produced at the time of booking, arrives at the airport and goes to the appropriate check-in desk, where all of the necessary information is available on the computer terminal to allow the passenger to travel.
Airlines and many other booking systems use real-time processing for transactions like the process described above.
Whenever a transaction occurs, the system is automatically updated, whatever the time is. In the case of airline booking, this avoids double-booking of seats. Where one traveller books a ticket at one travel agency, and it is the last available seat on the plane, real-time processing immediately allows the system to note that the plane is now full, so that, if another passenger tries to book a ticket on the same plane a few minutes later, the display will show that there are no more seats.
Real-time processing is also used in the context of many retail stores, and in warehouses. As soon as an item is sold or used, the system immediately deducts it from stock, so that the stock position is always accurate.
Real-time processing is essential in control systems, where data from sensors is entered into the system and processed to provide immediate feedback to the device being controlled. It would be a traffic disaster if traffic lights changed 20 minutes after sensors registered a large number of vehicles waiting. Similarly, if a robot did not carry out its task at exactly the right moment on a production line, there could be chaos.
Batch processing is used in contexts where it makes sense to collect together a lot of inputs of different kinds and then process them all in one go, or batch. A gas supply company, for example, is likely to use batch processing to produce its bills. Data of several different kinds will be processed in the batch to produce the bills. This will include customers’ account numbers, previous gas meter readings, present gas meter readings, any new customers and different tariffs (gas supply prices) that may be offered.
KEY POINT - The advantage of batch processing is that the computer operator can enter all the data for one batch in one operation. The software will carry out the various processes required and the final result is a bill for each customer, and an updated master file of customer information.