Question

Using your knowledge of how an ATM is used, develop a set of use-cases that could serve as a basis for understanding the requirements for an ATM system.

Short answer

The main use-cases for an ATM include withdrawing and depositing cash, checking balance, transferring funds, changing PIN, and printing a mini-statement.

Step-by-step solution

- Identify Actors

Begin by identifying the main actors involved in using an ATM. The primary actors are the customer and the bank.

- Define Use-Case: Withdraw Cash

A customer wants to withdraw cash from their bank account using the ATM. This involves inserting a bank card, entering a PIN, selecting the "withdraw cash" option, choosing the amount, and retrieving the cash if the account has sufficient funds.

- Define Use-Case: Deposit Cash

The customer may want to deposit cash into their account using the ATM. This requires inserting the bank card, entering a PIN, selecting the "deposit cash" option, inserting cash, and obtaining a receipt for the deposit made.

- Define Use-Case: Check Balance

Customers often use ATMs to check their account balance. This process involves inserting the card, entering a PIN, selecting the "check balance" option, and viewing the account balance on the screen or printing it.

- Define Use-Case: Transfer Funds

A customer may transfer funds between accounts. They need to insert their card, enter a PIN, select the "transfer funds" option, choose the accounts and amount, and confirm the transaction.

- Define Use-Case: Change PIN

For changing a PIN, the customer must insert their card, enter their current PIN, choose the "change PIN" option, and follow prompts to enter a new PIN, confirming it by re-entering.

- Define Use-Case: Print Mini-Statement

This use-case involves the customer printing a mini-statement of recent transactions. They insert their card, enter the PIN, select the "print mini-statement" option, and collect the printed statement.

Key concepts

ATM System

An Automated Teller Machine (ATM) system serves as an interaction point between a customer and a bank, facilitating essential banking tasks quickly and efficiently. ATMs provide convenience as they are accessible 24/7, and offer various banking services, reducing the need for teller interactions at a physical bank.

The basic features of ATM systems include handling cash withdrawals, deposits, balance inquiries, fund transfers, PIN changes, and printing mini-statements. These systems are equipped with hardware components like card readers, keypads, screens, and cash dispensers, along with security features to protect user data and transactions.

The functionality of an ATM is guided by software that processes user inputs, interacts with the bank's central system, and ensures the completion of transactions in a secure manner. Each action taken by a customer, from card insertion to cash retrieval, is part of a well-defined series of steps managed by the ATM's software.

Requirements Gathering

Requirements gathering is a critical aspect of developing an ATM system, as it ensures the system meets the needs of both the bank and its customers. This stage involves identifying and detailing the essential functions the ATM must perform.

Several methods can be employed during requirements gathering, such as conducting interviews with stakeholders, field observations, and gathering user feedback. The goal is to capture both functional requirements (what the system should do) and non-functional requirements (how the system should perform).

Commonly identified requirements include security protocols, transaction reliability, user friendliness, and system scalability. By thoroughly understanding these requirements, software developers can create an ATM system that satisfies user expectations and operational objectives.

Software Engineering

Software engineering for an ATM involves designing and implementing software to control its hardware components and manage user transactions. This process requires a structured approach to ensure the system operates efficiently and securely.

Key stages in software engineering for an ATM include:

• **Design**: Crafting a blueprint for the software that satisfies all functional and non-functional requirements. This involves creating use-case diagrams and defining system architecture.
• **Development**: Writing the actual code and integrating it with the ATM's hardware components.
• **Testing**: Ensuring the software works as intended through rigorous testing scenarios to identify and fix bugs.

Adhering to software engineering principles helps ensure the ATM system is robust and maintainable over its lifecycle.

User Interaction

User interaction with an ATM is designed to be straightforward and intuitive, ensuring users can perform their transactions with minimal difficulty. This interaction mainly occurs through the ATM's interface, which includes the screen, keypad, and card reader.

The interface guides users through each transaction step-by-step, providing clear instructions and prompts. This design helps reduce errors and increase user satisfaction.

Good user interaction design considers:

• **Simplicity**: Avoid overwhelming the user with too many options at once.
• **Feedback**: Promptly inform users of transaction statuses and errors.
• **Error Prevention**: Minimize mistakes by providing input validation and confirmations before critical actions.

An efficient user interface in ATMs improves usability and enhances the customer experience.

System Design

System design for an ATM encompasses the planning and architecture necessary to ensure the ATM fulfills its intended functions reliably and securely. This involves choosing appropriate hardware, software, and network configurations.

Key considerations in ATM system design include:

• **Security**: Protecting transactions and user data using encryption and access control mechanisms.
• **Redundancy and Resilience**: Ensuring continuous operation even in case of hardware failures or network issues.
• **User Accessibility**: Designing interfaces that are accessible for all users, including those with disabilities.

The system design phase sets the foundation for the subsequent development and operational stages, ensuring that the ATM performs its tasks efficiently while meeting all specified requirements.