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Protocol and Protocol Converters
One of the most frustrating aspects of data communications between different types of computers, especially between a microcomputer and a larger computer system, is that they often use different communications protocols. A protocol is the formal set of rules for communicating, including rules for timing of messages, the type of electrical connections used by the communications devices, error detection techniques, means of gaining access to communication channels, and so on. To overcome this problem, a specialized type of intelligent multiplexer called a protocol converter can be used. Protocol converters are available that even allow a microcomputer operating in asynchronous mode to talk with a large IBM mainframe operating in synchronous mode. This type of device is being used more and more companies that want to establish effective communications between personal computers and the main computer system and with printing devices.
Some groups are working on the establishment of a standard protocol for data transmission. For example, IBM has released the Systems Network Architecture (SNA) for its own machines, and the International Standards Organization (ISO) has released its set of protocol standards called the Open Systems Interconnection (OSI). However, just because standards exist does not mean that they will be used by everyone or that they can be enforced.
Exercises:
1. Give Russian equivalents of the following phrases:
The main computer is connected directly; traffic management and communications functions; as a ‘mediator’ between the network and the main computer; especially between a microcomputer and a larger computer system.
2. Say if the following sentences are true or false.
1. In some computer systems, the main computer is connected directly into the multiplexer, controller, or concentrator. 2. In effect, the front-end processor doesn’t act as a ‘mediator’ between the network and the main computer, allowing the main computer to concentrate on processing and improving the responsiveness of the system to the user. 3. Some groups aren’t working on the establishment of a standard protocol for data transmission. 4. Protocol converters are available that even allow a microcomputer operating in asynchronous mode to talk with a large IBM mainframe operating in synchronous mode. 5. However, just because standards exist means that they will be used by everyone or that they can be enforced.
3. Insert missing words, use the text’s vocabulary:
1.In other systems, it is first hooked to a … processor, a smaller computer that relieves the larger one of many data traffic management and communications functions. 2. To overcome this problem, a specialized type of intelligent multiplexer called a … … can be used. 3. Protocol converters are available that even allow a microcomputer operating in asynchronous mode to talk with a large … mainframe operating in synchronous mode.
4. Translate these sentences into your native language:
1. This type of device is being used more and more companies that want to establish effective communications between personal computers and the main computer system and with printing devices. 2.Some groups are working on the establishment of a standard protocol for data transmission. 3.Protocol converters are available that even allow a microcomputer operating in asynchronous mode to talk with a large IBM mainframe operating in synchronous mode. 4. In effect, the front-end processor acts as a ‘mediator’ between the network and the main computer, allowing the main computer to concentrate on processing and improving the responsiveness of the system to the user.
Retell the text.
Text 19