1. Investigation
In this step of processing, the nature of the problem, the cause of the problem and the possibility of solving the problem are considered. The factors that are considered in this step of information search are:
(i) To know about existing procedures and to inspect if necessary.
(ii) System selection through survey work
(iii) Possibility of system solution
(iv) To judge the feasibility of the system and
(v) Preparation of reports.
Then data is collected from reports, documents etc. and decisions are made about the objectives, features and other necessary aspects of the proposed method. The feasibility of the system is judged by comparing and analyzing different systems. System Feasibility Report is prepared after data analysis. The report covers the following topics--
(i) Basic description of the proposed system including features,
(ii) the economic, technical, institutional and managerial feasibility of the proposed approach and
(iii) Outline of proposed method development.
2. System Analysis
System analysis is a method by which the components and content used in the system are analyzed to diagnose problems, identify the causes of problems, collect data and develop new systems to solve problems. The system analysis process starts after the feasibility report is approved by the management authority. This step identifies the data processing problem and analyzes the various ways to solve it. The system analysis step is very important. Because the main purpose of data processing is precisely identified here and based on this the subsequent tasks are carried out. Factors such as mechanical equipment, software, manpower used in the organization to convert data into valuable information are considered. It is necessary to analyze how all these assets of the organization help in data acquisition, processing, storage of information and delivery of results. After specifying the required issues, reports are prepared on these issues.
3. System Analysis Tools
The tools commonly used to perform system analysis for system design and development are called system analysis tools. Analyzing the system properly is very important for designing the system. That is why system analysis is called the processor 'heart'. There are a number of tools for comprehensive system analysis, namely—
(i) Data Flow Diagram
(ii) Data Dictionary
(iii) Structure English
(iv) Decision Tree
(v) Decision Table and
(vi) System flow chart etc.
Data Flow Diagram: An important step in system analysis is to create a data flow diagram or DFD. With the help of data flow diagram, the essential components of the system and their changes are represented through diagrams. It is also called a 'bubble chart' because the data flow diagram is created by connecting several 'bubble' lines. Bubbles represent system data changes and lines represent data flow.
Data Dictionary: Data dictionary is a container that contains metadata. By Metadata, we generally mean the data related to the data. When a new system needs to be introduced, the properties, goals, names, etc. of the data used in that system are stored for the future. The information contained in the data dictionary is--
(i) Name of each data and its characteristics
(ii) Type of each data such as— its length
(iii) Data has no specific obligations
(iv) Correlation between different data
(v) who controls any data and
(vi) Figures of different numbers.
Data dictionary is very important in database creation. A publishing organization's data dictionary contains the names of all the components used in their system. For example, a book information file may contain the following data elements__
Data Dictionary
Book Information File
Book Number
Customer Information File
Member Number
Unit Price
Authore
Quantity
Name
Address
Credit Limit
Credit
ENDIF
Decision Tree: Decision tree is a system analysis tool, through which the system analyst presents the logic of the system policy very easily. A decision tree has many branches, which express alternative logic. Decision trees are very simple to draw and can be easily modernized
Decision Table: A decision table is a system analysis tool that combines problem description and actions. It expresses the relationship between the conditions and activities of a problem. A decision table consists of three parts, namely-
(i) condition or
(ii) Verb or action
(iii) Rules.
Condition: In order to make a decision, it is necessary to specify the parameters associated with the event, which are considered as decision conditions. Each condition or conditional action may or may not occur. But no condition can occur partially. In case of multiple conditions the conditions can be of different formats. For example - 2^3 or 8 arrays in case of three conditions or 2^4 or 16 arrays in case of 4 conditions.
Action: Possible actions under different conditions are called actions.
Rule: Any action or action based on the conditions of an event is called a decision rule.
Rules for making decision table:
The system analyst has to follow the following steps to create a decision table. namely--
Step-1: The various conditions of the incident must be specified.
Step-2: Specify the possible actions or actions for different conditions.
Step-3: Specify the decision rules and fill the decision table with the help of decision rules.
Difference between Decision Table and Decision Tree:
| Decision tree
1. A decision tree is a tool through which the system analyst can easily visualize the logic of the system policy. System policy can be expressed in the form of branches in a decision tree.
2. A decision tree has many branches, which express alternative logic.
3. Decision trees are very simple to draw and can be easily modernized.
4. Structural issues of system policy in decision trees.
| Decision table
1. A decision table shows a problem description and actions together.
2. A decision table expresses the relationship between the conditions and actions of a problem.
3. A decision table consists of three parts, namely - condition, action and rule.
4. Decision tables are relatively difficult to create and modernize.
5. The decision table system can display structural issues of policy and direct actions.
System Design
Determining the basic outline of a new system by making necessary modifications to the existing system to solve the problem is called system design. System analysis begins after finalizing the data processing method report created for the user system design work. In most cases, if a complex problem is properly analyzed, its simple solution comes out.
To solve the problem, the system design process is divided into two parts:
1. Logical Design and
2. Physical Design
1. Logical Design: Logical design contains instructions for input-output, processing, control and storage etc of the system.
2. Physical Design: Physical design consists of schematic diagram of system input-output system, system and processing rules.
The system design report specifies the requirements for the system. The system design report covers the following topics:
System Description: This part describes the purpose, characteristics, structure of the system, requirements for the system and various steps of the system.
Specification of data and results: specification of data and results structure, physical and receiving/output mediums, such as video displays, audios, forms, reports, documents etc.
System Flow Chart: With the help of flow chart, the procedure of data processing and the location of various steps are shown.
Software Specification: The software and its component programs are specified for the proposed system.
Database specification: structure of database, contents, storage medium, connection mechanism, result serving and database maintenance etc.
Hardware Facilities: All facilities including equipment required for the proposed procedure and their efficiency and effectiveness.
Manpower: The manpower required to operate the system and their responsibilities.
System Management Manual: A manual of helpful instructions for personnel engaged in the proposed system management.
4. Software Development
After creating the system design report, the software development part begins. In this part all the program creation and its testing work is to be completed. Besides, the continuation of the use of the programs is also determined at this stage. Essentially, system development is a collective task and program development requires close communication between the system user, the system analyst, and the program writer.
5. System Implementation
In this part of system implementation, necessary software and equipment are implemented and tested, document preparation etc. is done. This section also deals with creating suitable manpower to manage the process through training. Also the manpower, rules, machinery, nature and structure of input-output data and database etc. of the old or existing system have to be changed to suit the new system. The fewer such changes required, the better. Because in this case a new method has to be implemented by changing the existing situation by carrying out the necessary procedures in a few steps. Implementation of a system according to the plan is called conversion of the plan. Completing a system upgrade as planned is called phase conversion. Parallel conversion is the combination of old and new systems.
6. System Maintenance
Required to monitor system performance for necessary changes, enhancements or improvements. It should be observed whether the objectives and goals of the system are properly implemented or not. It is normal to make mistakes due to inexperience in operating the system at initial stage. Many mistakes are eliminated as the operators experience increases. In this case, unexpected errors and problems are eliminated through maintenance. The main tasks of system maintenance can be divided as follows--
(i) System Hardware Maintenance
(ii) System Software Maintenance and
(iii) System Document Maintenance.
System Hardware Maintenance Most of the equipment used in the system is electronic. So care should be taken to avoid damage to any equipment due to electrical short circuit, high-voltage or voltage. Apart from that, the equipment must be protected from dust, liquids, humidity or cleanliness.
7. System Software Maintenance
Ready-made software and developed (Deleloped) software are used in the system. The hard copy and soft copy of the source code of the developed software should be kept carefully, so that if the installed software is damaged due to any reason, it can be re-installed from the source code. Apart from that, at least one copy of ready-made software should be kept with serial number or key.
Viruses can infect computer systems and cause system malfunctions. So always be aware of viruses. An effective role against viruses should be taken by acquiring or developing the latest version or versions of antivirus programs. Prevention is wiser than cure. So care should be taken to prevent the virus from infecting.
8. System Document Maintenance
System manuals, manuals of developer software, manuals of ready-made softwares and other necessary documents and source codes should be stored carefully.
Sample System Analysis
Example-1 : A member of Computer Club of Bangladesh Technical College usually gets 20% discount if he buys books. However, if the value of the books purchased by the member is more than 2000 rupees, then 25% discount is given. General buyers or non-members do not receive discounts. But if you buy books more than 2000 rupees then get 10% discount.
Comments
Post a Comment