System Development Cycle I

Welcome to SS2 Third Term!

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In today’s Computer Science class, We will be discussing System Development Cycle. We hope you enjoy the class!

SYSTEM DEVELOPMENT CYCLE

Information systems are important for the success of any modern business or an organization. Every many information systems are being developed to make them more competitive and improve productivity and profit.

The two keys required for the successful development of an information system are:

Thorough Systems analysis and design
Understand what the Business or organization requires.

Definition of terms

Systems analysis is the process of understanding in detail what a system should accomplish, how it will accomplish it required to accomplish it.

Systems design is the process of specifying in detail how components of an information system should be implemented physically.

A systems analyst is a person that uses analysis and design techniques to solve business problems using information technology.

Skills of a systems analyst

To be a good and successful systems analyst, the person must have the following skills:

Information technology knowledge and programming expertise.
Understand business problems.
Use logical methods for solving problems.
Ability to find facts about the problem and develop how it should be solved.
Always wanting the improvement of the system.
People management knowledge and skills.

Systems Analyst Problem-solving Approach

The steps taken by a system analyst to solve problems are stated below:

Study and understand the problem: The analyst must identify that there is a problem to be solved and specify that it is feasible to solve the problem.
Define the requirements for solving the problem: The analyst will identify the facts or data that are required to solve the problem.
Develop a set of possible or alternative solutions: If there are alternative solutions, the systems analyst must develop them and decide on the best solution to use. However, in most cases, there may be only one solution which is chosen.
Define the details of the chosen solution: All the facts and method need to solve the problem are specified in detail.
Solve the problem: The problem is solved using the chosen solution method.
Monitor to ensure that desired result or outcome is accomplished: Here, the analyst will make sure that the formula is not miscalculated.

Example:

Let us apply this process in solving a simple interest (SI) problem: A man invested the sum of N500, 000.00 for 5 years at an interest rate of 12% per annum. Calculate the amount at the end of the period.

Solution

Step1: Study and understand the problem: the simple interest is understood as defined.

Step 2: Verify that the benefits of solving the problem outweigh the cost: The SI can be solved with our current knowledge and the resources that we have like four-figure tables, calculator and so on. We do not need to hire anybody.

Step3: Define the requirements for solving the problem: the requirements for solving the SI problem are Principal (N500, 000.00), rate (12%) and Time (5years).

Step4: Develop a set of possible or alternative solutions: The problem can be solved in two ways: First calculating the SI using the formula (I=P*R*T/100) and then calculate the amount as A=Principal + Interest. Secondly, another way is calculating the Amount using the formula that A=P (1+(R*T/100))

Note that *means multiplication.

Step 5: Decide which solution is best and recommended: We decide to use the first method because it is simpler than the second.

Step 6: Define the details of the chosen solution: The variables (facts) that we need to solve this problem are as stated in step 3 above and the procedure are as stated on step 4(1) above.

Step 7: Implement the solution: The problem is solved as follow:

I=
$I = \frac{P \times R \times T}{100} = \frac{500000 \times 12 \times 5}{100} = N 300, 000 A m o u n t = P + I = N 500, 000 + 300, 000 = 800, 000$

Step 8: Monitor to ensure that the desired result is accomplished. To make sure that the formula procedure and calculations are correct.

CONCEPT OF SYSTEMS

What is a system?

A system is a collection of interrelated components that function together to form a whole and achieved the outcome. Examples:

What is an information system?

An information system is a collection of interrelated components that collect, process, store and provide as an output the information needed to complete a (business) task.

In systems development, application systems are referred to as information systems. Therefore, an information system can also be defined as a collection of programs running on computers which interact with one another as well as humans to provide the necessary information needed to make decisions within an organization.

What is a subsystem?

A subsystem is a part of a larger system that can function on its own to perform a task. It can be a system having subsystems or it may just be a single system. The components that make up the overall computer system can be described as sub-systems. These are mainly hardware and software subsystems. The process of dividing a system into subsystems and components is called Functional Decomposition.

Information systems and subsystems

A school information system will have the following subsystems: Academic system, Examination Systems, Discipline system, Hostel/Accommodation system, Library system, Fees Billing System, Staff System, Bursary System and so on.

Information Systems and Component Parts

The main components of information systems are: