Identifying Inputs and Outputs (OCR A-Level Computer Science): Revision Notes

Identifying Inputs and Outputs

Overview

Every computer system or programme requires inputs and outputs to function effectively. Inputs are the data or signals received by the system, while outputs are the results or responses produced by the system. Understanding the relationship between inputs and outputs is fundamental in designing programmes and solving problems in computer science.

In this topic, we will explore the nature of inputs and outputs, the different formats they can take, and how to identify them in various scenarios.

Inputs

• Definition: Data or signals provided to a system for processing.
• Examples of Inputs:
  • Digital Inputs:
  • Keyboard entries (e.g., typing text into a form).
  • Mouse clicks or touchscreen interactions.
  • Sensor readings (e.g., temperature from a thermometer).
  • Analog Inputs:
  • Sound captured by a microphone.
  • Light intensity is measured by a photo sensor.
  • Predefined Data Inputs:
  • Values from a database or file.

Outputs

• Definition: Data or signals produced by a system after processing.
• Examples of Outputs:
  • Digital Outputs:
  • Displaying text or images on a screen.
  • Sending data to a file.
  • Hard Copy Outputs:
  • Printing a document or report.
  • Analog Outputs:
  • Sound output from a speaker.
  • Controlling the brightness of a light.

Types of Inputs and Outputs

Digital Inputs and Outputs

• These are discrete values, often represented in binary (e.g., 0s and 1s).
• Examples:
  • Input: Button presses, typed commands.
  • Output: Text displayed on a monitor, data stored in a file.

Analog Inputs and Outputs

• These involve continuous signals and are often used in real-world monitoring and control.
• Examples:
  • Input: Sound waves captured by a microphone.
  • Output: Voltage changes controlling a motor's speed.

Hard Copy Outputs

• Permanent physical copies of data.
• Examples:
  • Printouts of invoices, charts, or tickets.

Identifying Inputs and Outputs in Scenarios

Scenario 1: ATM Machine

• Inputs:
  • Card inserted by the user.
  • PIN entered via the keypad.
  • Option selected (e.g., withdraw cash).
• Outputs:
  • Digital: Information displayed on the screen.
  • Hard Copy: Printed receipt.
  • Physical: Dispensed cash.

Scenario 2: Temperature Monitoring System

• Inputs:
  • Temperature readings from a sensor.
• Outputs:
  • Digital: Temperature displayed on a monitor.
  • Hard Copy: Printed log of temperature data.
  • Analogue: Signal sent to a cooling system if temperature exceeds a threshold.

Scenario 3: Online Shopping System

• Inputs:
  • Product selections via a web interface.
  • Payment details entered (e.g., credit card number).
• Outputs:
  • Digital: Confirmation message displayed to the user.
  • Hard Copy: Printed receipt or delivery note.

Scenario 4: Quiz Game Program

• Inputs:
  • User answers via keyboard or touchscreen.
• Outputs:
  • Digital: Scores are displayed on the screen.
  • Hard Copy: Option to print a certificate.

Benefits of Understanding Inputs and Outputs

1. Improved System Design: Knowing the inputs and outputs helps in designing user-friendly and efficient systems.
2. Accurate Data Processing: Ensures the correct data is collected and the appropriate results are generated.
3. Enhanced Troubleshooting: Understanding the input-output relationship helps diagnose issues in programme functionality.

Note Summary