By the end of the lesson, the learner should be able to: Describe various methods of system Development Describe structured system development method
System development involves identifying business requirements and developing information systems that will effectively help to support the day-to-day operations & decision-making processes in an organization.
Definition of a System
A System is a set of organized components which interact in a given environment and within a specified boundary to achieve collective goals & objectives that are emerging.
A System is a set of items, equipments, procedures, processes, techniques, programs & people working jointly with an aim of achieving common goals.
Examples of systems are:
A system is made of various components. Once the components come together, they become interrelated to each other and generate new goals and objectives, and as such, a system breaks down when any of its components is removed.
E.g., a Bicycle system has all the components working together to provide motion when ridden. The individual components cannot provide these services to a rider when on their own.
A system does some useful job; hence, it should be active & efficient, e.g., a Banking system deals with money.
Description of a System
A system can be described as either being Soft or Hard.
These are usually the human activity systems.
They are described as soft because of 3 main reasons;
Examples of soft systems:
A Political system: - it is very difficult to come up with a system that will predict the political mood in a country over a given period of time.
A sales tracking & prediction system in an organization: - sales in an organization depend on human factors such as attitude in the market place.
These are systems whose goals & objectives are clearly defined, and the outcomes from their processes are predictable and can be modeled accurately.
Hard systems are based on proven scientific laws such as mathematical formulas or Engineering solutions.
Example of a hard system:
Stock management system in a supermarket: - it is possible to know exactly the stock levels, cost, selling price, and to predict accurately the profit if all the stock is sold.
Note. A good system should have features of both soft & hard systems, e.g., a stock management system should be able to show when the demand for a certain item rises so that a decision can be made on when to buy more stock. Similarly, new demand is driven by soft aspects in people’s lives such as attitude & seasons.
CHARACTERISTICS (FEATURES) OF A SYSTEM
All systems have some common characteristics. Some of these characteristics are:
A system contains a set of interacting elements. However, in holistic thinking, a system is considered as a whole unit.
Note. The concept of a system emerged from early psychologists who believed that the mind was a whole unit, rather than a collection of psychological parts.
The various components that make up a system may be simple in nature, but when combined, they create something complex whose overall goals are more sophisticated than those of the individual components.
A system must be designed to achieve a specific predetermined objective, e.g., one main objective of a school system is to enable the students to excel in national examinations.
The objectives that a system is supposed to achieve will enable the system developers measure the performance of the system during its operation.
System boundaries and environment
Each system is required to operate within a specific framework or limits. The space within which the components of a system operate is known as its boundary. Outside this boundary is the environment, from which inputs are received & to which outputs are communicated.
Entities that fall outside the boundary but interact with the system are called external entities, and they form part of the system environment. External entities provide the inputs & also receive the outputs from the system.
e.g., the external entities to a school system may include; Parents, various suppliers, and the society.
Therefore, a system operates within specified boundaries, and interacts with other systems.
Each system is made up of different components (or other systems) that communicate with each other. These systems are described as Sub-systems.
This means that, a system does not exist alone, but it is composed of subsystems, which are also made up of other subsystems.
The Classroom system is part of a School system, which is a subsystem of the Ministry of Education. The Ministry of Education is part of the Government, while the Government is part of the Global system.
Therefore, every system is a component of a larger system.
Inputs & outputs
A system communicates with its environment by receiving inputs & giving outputs.
A manufacturing firm can be considered as a system that gets inputs in form of raw materials from the environment and transforms them into finished products (outputs), which are released into the environment.
A system will usually transform data from one state to another.
Usually, after the raw data is collected & prepared into a form suitable for input, it is then manipulated into information using the given procedures or instructions. The processing may be manual, clerical, electro-mechanical or automatic to obtain the information.
A system has some controls that help it not to operate beyond its boundaries. Control is the method by which a system adapts to changes in the environment in order to give the expected output or to perform to the expected level.
Control is normally achieved through feedback. Feedback is a check within a system, which ensures that the objectives of the system are achieved. They assist the system by monitoring the environment in which it operates in order to find out any deviation. If any deviation is detected, then the appropriate steps are taken to rectify this error.
The feedback may involve having the outputs from the process of the system being fed back to the control mechanism. The control mechanism will then adjust control signals that are fed to the process, which then ensures that the output meets the set expectations.
The figure below shows a system that has feedback to the control function.
A motor vehicle manufacturing company is expected to produce several vehicles per day. If the demand increases, the feedback will show that the company is underperforming. Control signals can then be issued to speed up the movement of units on the Assembly line so as to increase production.
System entropy (decay)
A system slowly becomes useless to the user either due to improvement in technology, new management policies or change in user requirements.
Therefore, a system must be reviewed with the aim of improving it or to developing a new one.
A system must give priority to the objectives of the organization as a whole as compared to the objectives of a subsystem.
Open and Closed systems
A system can be described as being open or closed.
An Open system is that which interacts and communicates with its environment constantly. It receives inputs from & gives output to the environment.
Examples of open systems;
A Closed system is that which does not interact or communicate with its environment. It does not communicate to or receive communication from its environment.
Closed systems do not receive inputs or give output to their environment.
Example of a closed system;
a). What is system Control?
b). Why do we need feedback in a system?
c). Draw a well-labelled diagram that shows a system that is controlled through feedback.
(d). Distinguish between open and closed systems.
Definition of an Information system:
An Information system is an arrangement of people, data processes & information that work together to support and improve the day-to-day operations in a business and the decision-making process.
Generally, the Information system of an organization is the complete apparatus for handling all aspects of information within an organization. It includes people, procedures, technological, and other resources that collect, transform & disseminate information in the organization.
Purposes of an Information system:
The main purposes of an Information system in an organization are: -
The process whereby a computer-based information system is used to capture operational data, analyze it, and generate reports that can be used to support the decision making process in an organization is referred to as Online analytical processing.
Supports sharing of information between departments/users in a given organization. The departments can share the same electronic information stored in central database.
Circumstances that necessitate the development of new Information systems:
The following are some of the circumstances that bring about the need to develop new information systems:
New opportunities: - a chance to improve the quality of internal processes and service delivery in the organization may arise.
Invention of new systems which are more successful than the existing ones.
Problems: - the user may encounter some difficulties in the operations of the existing system, which prevent the organization from meeting its goals.
The management may identify an area of poor performance, which increases the level of indirect expenses.
Directives: - these are requirements imposed by the management, government, or external influences.
System Analysis and Design
System design is the activity that involves identifying possible solutions to a problem, and then deciding on the most appropriate system to solve the problem.
System design is concerned with the design of a computerized application based on the facts disclosed during the Analysis stage.
In system design, the nature & contents of inputs, files & outputs are formulated and described in order to show how they are connected by processing procedures, and for the purpose of developing a new (or, an improved) system.
Information system Analyst:
An Information system Analyst is a person who identifies the problems & needs of an organization, then designs & develops algorithms and procedures on how to solve these problems on a computer.
The Analyst uses scientific techniques so as to determine where & how improvements can be made in order to meet objectives in a more efficient, efficient, and economical manner.
Roles of an Information system analyst
Define the following terms:
State and explain three purposes of Information systems in organizations.
Highlight three circumstances that necessitate the development of new information systems.
List down four roles of an Information system analyst.
THEORIES OF SYSTEM DEVELOPMENT
There are 3 main theories or methods used in system development.
In the Traditional approach, there is no formal documented methodology to be followed by all system developers in the organization.
The method relies mostly on the skills & experience of the individual members carrying out the project development.
Disadvantage of traditional approach.
The structure of the old system is not changed in anyway; hence, the weaknesses of the old system are not corrected, and are carried forward to the new system.
In a Bank, a manual system is characterized by long queues & poor controls. If the Traditional approach is used, each Cashier will simply be given a computer. The long queues might remain and lack of controls increase because no value was added to the old information system.
Rapid Application Development (RAD).
This method heavily relies on Information Technology (computers). This is because; there is need for businesses or organizations to develop & implement information systems quickly enough for them to maintain a competitive advantage in the market.
Advantage of RAD.
Disadvantage of RAD.
Approaches used in Rapid Application Development.
There are 3 different approaches/techniques used in Rapid Application Development;
A Prototype is a small working model, which is developed to test ideas & assumptions about the new system.
Like any computer-based system, a prototype consists of working software that accepts input, performs calculations, produces printed or displayed information, or performs other meaningful activities. The design & the information produced by the system are tested & evaluated by the users.
Note. Use of prototypes makes it possible for system developers to quickly capture user requirements by designing system interfaces in the presence of the user.
In structured approach, there is a defined set of stages that should be followed when developing a system. Each stage is well documented and specifies the activities to be carried out by the system analyst and his team while developing a system.
(b) State the main advantage of Rapid Application Development method.
SYSTEM DEVELOPMENT LIFE CYCLE
The stages of developing a system are called the System development life cycle (SDLC).
The 7 main stages in system development include:
The following diagram represents the 7 stages, which must be followed in the system development life cycle: -
The life cycle of an information system is divided into 2 major parts: -
Note. Each stage serves a role in the problem-solving process, and therefore they must be followed systematically.
Problem recognition is done during the Preliminary investigation. A preliminary investigation is carried to find out if really there is need for change.
During the problem recognition stage, the system analyst seeks to answer two questions:
After this, the system analyst then defines the scope of the project and tries to establish the limitations (risks involved), the budget (i.e., cost, resources/manpower involved) & time involved.
Some of the most common limitations are:
Problem definition (Problem analysis)
Problem definition is the process of identifying & understanding the problem, and finding out any limitations that may limit the solution.
At this stage, the system analyst is required to find out much about the existing system (whether manual or computerised) in order to come up with a good & relevant proposal for the new system.
A special study called a feasibility study is carried out. A Feasibility study is a study carried out to establish the costs & benefits of the proposed new system.
The study tries to;
The feasibility of a system is accessed in 4 ways: -
This tries to establish whether the existing technology can be developed (upgraded) or is sufficient to support the new system.
It also tries to find out whether the staff has relevant technical skills to develop & use the new system.
Economic feasibility study tries to establish whether developing the new system is cost effective by comparing all the costs & benefits of the proposed system.
I.e., it tries to find out whether the expected benefits will exceed the costs of developing & operating the proposed system.
Operational feasibility is concerned with the operation of the office. It establishes whether the management, employees, customers, suppliers & other users are happy, willing and able to operate, use and support the proposed new system.
When carrying out operational feasibility study, the analyst tries to:
It establishes whether developing of the proposed system will be accomplished within the available time.
Note. This cost-benefit analysis study will then indicate whether the proposed system is viable or not. Otherwise, a new system should only be developed if its benefits are more than its costs.
After the feasibility study, a feasibility study report is produced, which outlines the following:
The recommendations contained in the report are carefully evaluated by the personnel involved in the system study, i.e., the management, user departments, steering committee, finance department, etc who will then decide on whether to commence a detailed investigation or not.
Information gathering (Fact-finding)
After the feasibility study report has been approved by the management, the system analyst then proceeds to identify the techniques that will help the management to gather enough information relating to the starting of the system.
The collection/gathering of all information required to implement a computer system is referred to as fact-finding.
Objectives of fact-finding.
The main objectives of fact-finding are:
The following are some of the common methods/techniques used to collect data:
Note. Before the system analyst chooses the most appropriate technique, he/she should compare the merits & demerits of each technique. This will ensure that the technique chosen will be able to meet all the requirements, which will assist the management in achieving its goals.
Document review (study of available documents):
This involves going through all the existing documents/records, which relate to the system being investigated in order to find out information that describe the data & procedures of the current system.
Examples of such documents are: -
Records inspection involves studying all the manuals maintained in connection to the system being studies. This helps the analyst understand the structure of the organization, its operation, and history.
Advantages of documents review
Disadvantages of documents review
This method requires the analyst to participate in or watch closely as a person performs some activities for a period of time in order to see for oneself what exactly happens in the system.
In Observation, the analyst asks no questions. Instead, he observes the actions in which he is interested, and records the desired information. This method gives the analyst first hand experience about the problems and exposes him/her to the system requirements.
Advantages of observation
The analyst is able to see clearly what is being done. He can also identify tasks, which have been omitted or inaccurately described by other fact-finding techniques.
Disadvantages of observation
Use of Questionnaires:
A Questionnaire is a special-purpose document that allows a person to collect information & opinions from respondents.
The method involves sending out forms containing questions with spaces for response to a group of people, and collecting the forms back after they are completed. This method allows the analyst to collect facts from a large number of people while maintaining uniform responses.
Circumstances in which a questionnaire is used for gathering information.
The questionnaires method is used in situations where:
Note. In a situation where a large population is to be questioned, the analyst may spend a lot of time analyzing the questionnaires. In such cases, a sample of people (who are assumed to represent the overall population), can be given the questionnaires.
Advantages of questionnaires
Disadvantages of questionnaires
Procedure for developing a questionnaire
Interviewing is the process of obtaining information from another party by means of conversation.
Interviews enable the system analyst (who is the Interviewer) to collect information from the affected individual (Interviewee) through face-to-face communication. The Interviewer asks questions and the Interviewee responds with answers.
The analyst should carry out interviews with the relevant stakeholders in order to get views about the current system, and gather information about the requirements for the proposed system.
Interviewing provides facts and also enables the analyst to verify the facts. It also provides an opportunity to meet & overcome any possible user resistance.
A good interview should be planned, and should be carried out at the most appropriate time for the parties involved.
When executing an interview, the following guidelines should be followed:
Advantages of interviews
Disadvantages of interviews
Automated data collection is mostly used when actual data is required but difficult to get through interviews, observation, or questionnaires.
Such data may be collected using devices that automatically capture data from the source such as Video cameras, Tape recorders, etc.
(b) Give one example of automated information gathering technique.
Fact recording takes place at the same time the analyst is gathering the facts. Facts relating to staff, operations, and processing tasks are recorded.
Fact recording is necessary because; the subsequent stage of system development shall depend on the facts recorded, i.e., the facts recorded will form reference material for the analyst during system design.
The various methods of fact recording are:
Preparing and presenting the fact-finding report:
After gathering the information/facts, the system analyst must come up with a requirements definition report, which must contain the following details:
This report is then presented to the Management for evaluation and further guidance.
In requirements specification, the system analyst must come up with detailed requirements for the new system.
The following requirements specifications are considered:
In system development, the output requirements of the new system are considered first. This is because; the main interest from a system is information (output), e.g., the main concern of a library management system is whether the system can generate reports on overdue books, charges of late return, inventory reports, etc.
The output is usually in the form of reports either in the form of hardcopy or softcopy.
The following factors should be considered when designing the output:
Target audience: - a user report may show only the transactions to be carried out, while the management would require a summary of the overall performance in the organization.
Frequency of report generation (i.e., the time at which the output is required): - some reports are required daily, others weekly, monthly or annually.
Quality and format of information to be generated.
Cost of producing the output: - the output should be at reasonable cost.
Mode of output & devices used for output, e.g., softcopy mode of output is produced through the screen.
After designing the output, it should be approved by the users, the management, and other staff within the organization who are affected by the change.
Once the system analyst has identified the output requirements for the new computerised system, he/she then identifies the input needed to obtain the relevant information from the system.
The input to the system is necessary because the contents input are used to maintain the master files.
The system analyst should therefore decide on:
After identifying all the inputs, the analyst designs the user interface by designing data entry forms or screens.
When designing the user interface, the following guidelines should be observed:
File requirements specification.
This involves identifying the files required to store data & information in the system.
The system analyst should:
An Attribute is a unique characteristic of a record for which a data value can be stored in the system database.
Note. These attributes are used when designing tables in a database, and each attribute becomes a field in the table.
A Books table will have the following attributes/fields: Book ID, ISBN number, Title, Author’s name, Year of publication, Date of issue and Date of return.
Factors to consider when designing a good file.
Record key field: - this is usually an attribute that is unique for each record.
Data type for each field: - each field has a data type. In a database, the data type of book titles can be stored as ‘Text’, while the Date of borrowing a book can be stored as ‘Date/Time’.
Length of each field: - a field used to store names can be specified to be 30 characters long, while a field used to store numbers/integers can be specified to be 10 characters long.
Backup and recovery strategies: - the updated copies of data & information files need to be stored in a different place other than the location of the current system. This ensures that, if the current file gets corrupted, the backed up data can be used to recover/reconstruct the original file.
Hardware & software requirements.
The system analyst should specify all the hardware & software requirements for the new system.
The hardware & software used to develop the system mainly depends on Input, Output & File requirements, e.g., if the system requires data in picture format, then an image capturing device such as a Digital camera or a Scanner must be used.
Some of the factors to consider in hardware & software specification are:
(b) Define the term ‘Attribute’.
(c) Explain why it is important to consider the file backup and recovery strategies during file design.
(d) Outline the factors that should be considered when sourcing for hardware and software resources required for a new system.
In the design stage, the analyst must come up with ways of solving the problem.
The following are some of the tools used for designing an information system:
A system flowchart is a tool that can be used for analysing processes. It allows one to break a process down into individual events/activities, and also display these events in a short form showing the sequential or logical relationships between them.
A system flowchart has its own set of symbols. The following are some of the common system flowchart symbols:
Designing a system flowchart.
A system flowchart gives a summary of how particular processes are done within the business organization.
The following are some of the important guidelines when designing a system flowchart:
After drawing the system flowchart, other design tools such as pseudocodes and program flowcharts can be used to extract the processing logic for each module in the system before system construction.
(b) Draw four system flowchart symbols and explain their functions.
System construction refers to the coding, installation and testing of the modules and their components such as outputs, inputs & files.
The purpose of the construction stage is to develop & test a functional system that fulfils the design requirements of a particular organization.
System construction is done by programmers.
System construction methods
To construct a system, the programmer can use the following programming techniques:
After constructing the system, it is tested by entering some test data to find out whether its outputs are as expected.
When the system is newly developed, it can be first tested using dummy (assumed) data, while real/live test data can be used for normal circumstances to find whether the system can detect & report errors.
System testing is carried out in order to achieve the following aims:
During system testing, the following details should be checked:
NB: System testing is an iterative process, and it ends only when the analyst & the other personnel involved are satisfied that when operational, the system will meet the objectives and the growing demands of the organization.
(a) Explain system testing.
(b) State the importance of system testing.
(c) Name three groups of people who are involved in system testing.
System implementation is the process of putting the new system in day-to-day operating environment for the users to start using it.
A system is put into use after it has been fully tested, well documented, and after training the staff who will be involved in the running of the new system.
In most cases, the implementation phase is faced with various problems. They include:
The areas to be addressed during system implementation include:
File creation and conversion:
Every time a new system is implemented, the format of data files might change or might require modification.
The files can either be created from scratch or those that were used in the old system can be converted to be used in the new system.
Therefore, file creation & conversion involves setting up of the master files that are to be used to support the information requirements of the new system.
The factors to consider during file conversion include:
After designing a new system, all the staff affected by the change should be trained properly on how to use/run the system.
The aims of the training are:
The following methods of training can be used depending on the requirements:
NB: The training should be well planned & the most suitable method that can meet the needs for all the stakeholders selected. Otherwise, if the staffs are not trained properly, the system implementation can fail leading to great loss of company resources.
Changeover is simply how to move from the old system and start using the new system.
The changeover should be planned & effected at the most suitable time for a smooth transition to the new system.
The following are some of the common methods/ways of system changeover:
Direct (straight) changeover:
Straight changeover is a complete replacement of the old system with the new system in one bold move.
In this approach, the old system is stopped & abandoned and the new system starts operating immediately.
This sudden change from old to new can be very inconveniencing in case the new system fails, faces problems, or in a situation where the users have not gained enough confidence to run the new system.
Direct changeover is likely to be used in situations where:
Advantage of Direct changeover.