- Mar 23, 2018
- - 0 comment
Data Processing in Computers: How it works
Data communication is the transmission of data and information from one computer to another across geographical areas. It is done by the implementation of standard methods to move the information. These methods include electrical signals carried along a conductor, optical signals along optical fibres and electromagnetic areas.
In cases of an office environment, the distance over which data travels is short. This allows digital data to be directly transmitted with two level electrical signals over simple copper conductors. Data communication involves transmission of digital messages to devices external to the message source. The maximum permissible transmission rate of a message is directly proportional to single power and inversely proportional to channel noise. Communication system targets providing the highest possible transmission rate at the lowest possible power and with the lowest possible noise.
Data conveyed to other computers pass through a medium or pathway called the communication channel. This includes a physical wire that connects communicating devices, a radio, laser or other radiated energy source that has no obvious physical presence.
The basic requirement for a communication system includes a sender, who creates the message to be transmitted, the medium which is the communication channel and the receiver who receives the message. Four major terms are used in data communication. These are data, signal, signalling and transmission. Data is the collection of unprocessed information which includes disorganized transaction information. Signals represent the electromagnetic encoding of data. Signalling represents propagation of signals across a communication medium. Transmission is the communication of data by the processing of signals.
In a digital communication channel, the information is represented by individual data bits which may be encapsulated into multi bit message units. A collection of bytes may be grouped into a frame or other higher level message unit. These multiple levels of encapsulation facilitate the handling of messages in a complex data communication network.
Three communication channels are simple, half duplex and full duplex channel.
The simple channel is a channel whose direction of transmission is unchanging. The half duplex channel is a single physical channel in which the direction may be reversed. The full duplex channels allow simultaneous message exchange in both directions.
Data transmission through a medium can be either asynchronous or synchronous.
In asynchronous transmission, data is transmitted character by character as input is entered via a keyboard. This brings about irregular gaps within the characters. It is cheaper and easier to implement since data is not saved before sending. Example is the yahoo messenger chat application through which data is sent and received asynchronously.
In synchronous transmission, saved data is transmitted block by block. This mode suits remote communication between a computer and a card reader or printer.
Data switching is the process of routing an input signal to an output signal with a data switch. Edge switches, backbone switches and core switches employ a number of specific interfacing technologies to carry out the process. These technologies include the optical fibre, 10 Gigabit Ethernet and stacked managed proprietary connections. In data switching, the data environment is ever changing. This is the power over Ethernet.
The data switch used reduces the effect of contention on network performance. The switch allows a device to fully utilize the full capacity of the network. The switch creates a temporary virtual circuit between the two devices that are attempting to communicate.
DATA COMMUNICATION EQUIPMENT
Data communication equipments are used to transmit or receive analogue or digital signals through a network. These equipments work at the physical layer of the open system interconnection model. It takes data generated by the data terminal equipment and converts it into a signal that can then be transmitted over a communication link.
The data connection equipment is also responsible for providing timing over a serial link. In a complex network, which uses directly connected routers to provide serial links, one serial interface or each connection must be configured with a clock rate to provide synchronization.
Examples of data communication equipment include modems, integrated service digital network adapter, satellites, microwave and network interface cards. The modem is a communication device that converts computer digital signals to analogue so that signals can be transmitted over standard telephone lines. It also converts analogue signals back into digital signals that a computer can process.
The ISDN adaptor is a DCE which has a set of standards for digital transmission of data over standard copper telephone lines incorporated in it. It functions with a modem.
The satellite is a microwave relay station placed in outer space. Microwave signal is transmitted from a transmitter on earth to the satellite at space. The satellite amplifies the weak signal and transmits it back to the receiver.
The microwave uses very high frequency radio signals to transmit data through space. All these are integrated in a network system to make the communication of data possible.
This is a facility used by trading members to the National Stock Exchange (NSE) to carry out their trading operations over a uniform network. The computer to computer link is only available to trading members.
The trading members can use their own software on any suitable hardware or as software platform of their choice. Members can customize the software to their taste. These include enjoying provisions like online trading analysis, risk management tools and back office operation integration.
STAND ALONE COMPUTERS AND MULTI USER SYSTEM
A stand alone computer is a computer that is not connected to another computer. It is a computer that is used on its own without requiring a local area network or wide area network. A computer that only allows information to be shared by printouts, floppy disks and compact disks is a stand-alone computer.
A stand alone computer could be connected to the internet but does not allow the access of external computer users. The connection to the internet is based on a network process that runs from the server to the computer.
A multi user system is a system that allows information to be shared over a local area network or wide area network. It makes work and communication efficient by enhancing faster passage of data over a network.
The multi user system shares devices like printer, hard disks, scanners and fax machines over a network. This system relies solely on networking software like windows server 2000 or Linux network server to run their operations. These softwares allow network administrators to define user privileges in order to control information access and manipulation over the network.
Multi user systems are mostly used in office environments and commercial sectors. These include schools, banks, finance houses, government parastatals etc. This development has really helped the economy by making exchange of goods and services easier and global.
CENTRALIZED DATA PROCESSING
Centralized data processing is a data processing architecture that allows data processing support to be provided to computers over a network. In the architecture of the centralized data processing, each person is provided with a local terminal that is connected by a communication system.
This system uses centralized computers, processing, data and control. This brings about economy of equipment and personal, lack of duplication, ease in enforcing standards and security.
DISTRIBUTED PROCESSING AND NETWORKS
Distributed processing involves a variety of computer systems that use one processor to run an application. This refers to local area networks that allow a single program to run simultaneously at different sites. The distributed processing systems contain sophisticated software that detects idle central processing units on the network and parcels out programs to utilize them. This system allows the storage of data on more than two computers with the use of database software like structural query language server. This is done so that the data won’t be lost if any one system runs down.
A Distributed processing runs on a distributed network. This is the network system that allows data to be spread over one or more computer to be processed. Distributed networking works with a combination of desktop workstations, local area network servers, regional servers, web servers and other servers.