37.Explain the important activities involved in system design.
The system design ijrocess,is.to obtain the objectives like practicability, efficiency, minimized cost, flexibility, and security of the system. It involves first logical design and then physical construction of a system. The logical design specifies the structure and characteristics of output, input, files, databases and procedures. The physical design involves the construction of actual program files and a working system. The design of a computerized inform-bop system can be divided into four main areas. They are 1. Output design 2. Input design 3. File design
4. System processing and general program design Output Design: For communicating the results of pro cessing to users, the 'output is a must. The selection of the medium of output is according to the requirement.
For temporary output, video display can be used. If the output is to be kept permanent, printouts can be taken. For storing files, magnetic disk or tape can be used If the amount of data is very large, microfilms are used The factors like usage, quality and cost must also be Considered. According to the usage, output can be divided into two groups-internal and external. Internal usage refers to, the use by employees within the organization whereas, the external usage intended to the pub¬lic. In internal copies, the formatting, print quality, paper quality etc are not important. But the external document are intended to the public image of a company,.it must be attractive and presented in a useful manner.
Input Design: Once the outputs have been decided upon, the next step is to find out what inputs are needed to produce these outputs. For this the sources of data must be identified first. The next step is to find the way to collect these data (data capture). Then the collected data are to be converted into machine readable form (data entry). Finally; these data are to be sent to the memory for processing with the help of a computer program (data input). The reliability of output prdduced by a system depends largely on the degree of accuracy of the data entering the system. So much effort has been made to reduce the possibility of errors at this stage. This can be achieved by reducing the human intervention. For this OMR sheets, Magnetic Ink Character Readers, Bar codes etc can be used In some cases, the data capture, data entry and data input can be combined to reduce errors in each stage.
File Design: After the outputs and inputs have been designed, the analyst must decide the method of storing the data and accessing the data This is called the file design. The above two problems are related. If the stor-age medium is magnetic tape, the data must be arranged sequentially. However, if disk storage is available, sequen
or direct access can be chosen. In file design the fol lowing terms are used.
Field: A field is the smallest unit of data
Record: The collection of related fields is called a record. File: A file is a collection of related records.- Example*. The students' details of a class.
Accessing Records: The three access methods are Serial access, Sequential access and Direct access.
System processing and general program design: After designing the outputs, inputs and files, the analyst must decide how the various parts* of the system will interact with each other to produce the desired outputs from the inputs, using files. Here, what data is to be edited or sorted, what files to update, how to perform update etc are to be decided. The processing of data through the system is via people and programs. The computer programs required for the system must be determined. For each program, the purpose, inputs and outputs are to be specified. The relationship between programs should also be specified. For specifying system processing a tool cailed system flowchart is used. In this, standard symbols are used to represent input, output and processing.of files.
38.Discuss the irnportant activities involved in system Implementation.
Implementation is the stage of a project during which the design of a system is tested, debugged and made operational. So it is the most crucial stage in achieving a successful new system and in giving the users confidence that the new system will work and be effective.
The following are the, major activities that comprise of the implementation stage.
(1) Develop detailed programming specifications. In this activity, the internal logic of the various modules such as algorithms, special techniques etc. are developed.
(2) Develop test specification and test data.The analysts decide how program testing should be done, for instance, which module should be tested first The specific areas where testing should be especially stringent must also be pointed out.
(3) Write computer programs. An appropriate programming language is selected for writing programs according to the type of processing involved.
(4) ltst computer programs. This activity determines whether the system is producing the results it was de-signed to produce. Errors in design and logic will be shown here. Programs are individually tested using the test data produced in the previous activity.
(5) User training. While computer programs are being developed andetested, the analyst will start familiarizing the users with the procedures to be used in the new system. The data entry operators must be trained to enter data from the source documents and correcting errors. For this, a user manual describing in detail the procedures to be followed should be developed and made. available to the users.
(6) System testing. After the computer programs have been written and tested, and users have been trained to use the systetn, a full system e test can take place. All aspects of the system are tested, from preparation of source document to the distribution of output.
(7) File conversion. File conversion is the process of converting data from the old system into the format needed by the new system.
(8) Change over to the new system
A new system was developed to improve the efficiency of the company operations by replacing an existing sys-tem. But the transition from old to new is not always an easy process. Resistance from the part of employees may happen. So the analysts must take care to make sure the user input and interaction.
The system design ijrocess,is.to obtain the objectives like practicability, efficiency, minimized cost, flexibility, and security of the system. It involves first logical design and then physical construction of a system. The logical design specifies the structure and characteristics of output, input, files, databases and procedures. The physical design involves the construction of actual program files and a working system. The design of a computerized inform-bop system can be divided into four main areas. They are 1. Output design 2. Input design 3. File design
4. System processing and general program design Output Design: For communicating the results of pro cessing to users, the 'output is a must. The selection of the medium of output is according to the requirement.
For temporary output, video display can be used. If the output is to be kept permanent, printouts can be taken. For storing files, magnetic disk or tape can be used If the amount of data is very large, microfilms are used The factors like usage, quality and cost must also be Considered. According to the usage, output can be divided into two groups-internal and external. Internal usage refers to, the use by employees within the organization whereas, the external usage intended to the pub¬lic. In internal copies, the formatting, print quality, paper quality etc are not important. But the external document are intended to the public image of a company,.it must be attractive and presented in a useful manner.
Input Design: Once the outputs have been decided upon, the next step is to find out what inputs are needed to produce these outputs. For this the sources of data must be identified first. The next step is to find the way to collect these data (data capture). Then the collected data are to be converted into machine readable form (data entry). Finally; these data are to be sent to the memory for processing with the help of a computer program (data input). The reliability of output prdduced by a system depends largely on the degree of accuracy of the data entering the system. So much effort has been made to reduce the possibility of errors at this stage. This can be achieved by reducing the human intervention. For this OMR sheets, Magnetic Ink Character Readers, Bar codes etc can be used In some cases, the data capture, data entry and data input can be combined to reduce errors in each stage.
File Design: After the outputs and inputs have been designed, the analyst must decide the method of storing the data and accessing the data This is called the file design. The above two problems are related. If the stor-age medium is magnetic tape, the data must be arranged sequentially. However, if disk storage is available, sequen
or direct access can be chosen. In file design the fol lowing terms are used.
Field: A field is the smallest unit of data
Record: The collection of related fields is called a record. File: A file is a collection of related records.- Example*. The students' details of a class.
Accessing Records: The three access methods are Serial access, Sequential access and Direct access.
System processing and general program design: After designing the outputs, inputs and files, the analyst must decide how the various parts* of the system will interact with each other to produce the desired outputs from the inputs, using files. Here, what data is to be edited or sorted, what files to update, how to perform update etc are to be decided. The processing of data through the system is via people and programs. The computer programs required for the system must be determined. For each program, the purpose, inputs and outputs are to be specified. The relationship between programs should also be specified. For specifying system processing a tool cailed system flowchart is used. In this, standard symbols are used to represent input, output and processing.of files.
38.Discuss the irnportant activities involved in system Implementation.
Implementation is the stage of a project during which the design of a system is tested, debugged and made operational. So it is the most crucial stage in achieving a successful new system and in giving the users confidence that the new system will work and be effective.
The following are the, major activities that comprise of the implementation stage.
(1) Develop detailed programming specifications. In this activity, the internal logic of the various modules such as algorithms, special techniques etc. are developed.
(2) Develop test specification and test data.The analysts decide how program testing should be done, for instance, which module should be tested first The specific areas where testing should be especially stringent must also be pointed out.
(3) Write computer programs. An appropriate programming language is selected for writing programs according to the type of processing involved.
(4) ltst computer programs. This activity determines whether the system is producing the results it was de-signed to produce. Errors in design and logic will be shown here. Programs are individually tested using the test data produced in the previous activity.
(5) User training. While computer programs are being developed andetested, the analyst will start familiarizing the users with the procedures to be used in the new system. The data entry operators must be trained to enter data from the source documents and correcting errors. For this, a user manual describing in detail the procedures to be followed should be developed and made. available to the users.
(6) System testing. After the computer programs have been written and tested, and users have been trained to use the systetn, a full system e test can take place. All aspects of the system are tested, from preparation of source document to the distribution of output.
(7) File conversion. File conversion is the process of converting data from the old system into the format needed by the new system.
(8) Change over to the new system
A new system was developed to improve the efficiency of the company operations by replacing an existing sys-tem. But the transition from old to new is not always an easy process. Resistance from the part of employees may happen. So the analysts must take care to make sure the user input and interaction.
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