Software Engineering Principles and Costs

Software Engineering

• Software Engineering is the discipline of building software using professional methodologies
• All developed economies rely on software, and software-controlled systems are becoming increasingly prevalent.
• Software engineering focuses on the theories, methods, and tools for professional software development.

The Costs of Software

• Software costs can significantly overshadow hardware costs.
• Software maintenance often costs more than initial development.
• Long-life systems may experience maintenance costs that are multiple times higher than development costs.

Software Project Failure

• Increasing system complexity creates demand for faster delivery and larger, more complex systems with previously unimaginable capabilities.
• Neglecting software engineering methods can lead to more expensive and unreliable software due to a lack of structured approaches.

Professional Software Development

• Refers to a disciplined process of creating software applications that meet specific requirements and quality standards.

Key Aspects of Software Engineering

• An engineering discipline utilizing theories and methods to solve problems within organizational and financial constraints.
• Encompasses all aspects of software production, including project management and development of tools for software production support.

Importance of Software Engineering

• Society relies heavily on advanced software systems.
• Using software engineering methods for software systems is generally more cost-effective than individual programming projects.
• The majority of system costs often involve changes after the software goes into use.

Software Process Activities

• Software specification: Customers and engineers define the software to be produced and its operational constraints.
• Software development: The software is designed and programmed.
• Software validation: The software is evaluated to ensure it meets the customer's requirements.
• Software evolution: The software is modified to accommodate changing customer and market demands.

General Issues Affecting Software

• Heterogeneity: Systems often operate as distributed systems across networks with diverse computer types, including mobile devices.
• Business and social change: Industries change rapidly, requiring agile software development and adaptation to new technologies.
• Security and trust: As software becomes increasingly integrated into daily life, trust and security are crucial.
• Scale: Software development encompasses various scales, ranging from small embedded systems to large-scale, cloud-based systems.

Software Engineering Diversity

• There is no universal set of software engineering techniques for all types of systems.
• Methods and tools used vary depending on the application, customer requirements, and team backgrounds.

Application Types

• Stand-alone applications: Execute on a local computer and include all necessary functionality.
• Interactive transaction-based applications: Run on remote computers and are accessed remotely.
• Embedded control systems: Control hardware devices.
• Batch processing systems: Process large volumes of data in batches.
• Entertainment systems: Intended primarily for personal entertainment.
• Systems for modeling and simulation: Emulate physical processes or situations with multiple interacting objects.
• Data collection systems: Collect data from sensors and process it.
• Systems of systems: Composed of multiple software systems.
• Rich interfaces: Web-based interfaces using technologies like AJAX and HTML5 to enhance user experience.

Case Studies

• A personal insulin pump: An embedded system that controls insulin delivery based on blood sugar levels. It is a safety-critical system.
• A mental health case patient management system (Mentcare): A system used for managing patient records.
• Insulin pump control system: Collects data from a blood sugar sensor, calculates the required insulin dose, and controls an insulin micro-pump. This system ensures safety and proper insulin delivery.

Activity Model of the Insulin Pump

• Activity Models focus on the sequence of activities and interactions within a process.
• Data Flow Diagrams focus on the movement and processing of data within a system.

Essential High-Level Requirements

• The insulin pump system must be available to deliver insulin whenever needed.
• The system should provide reliable performance and deliver the correct insulin dosage to manage blood sugar levels.
• The design and implementation must ensure consistent compliance with these requirements.

Explore the fundamental concepts of Software Engineering, from methodologies to project failures. Understand the significant costs associated with software development and maintenance, and learn about the importance of professional practices in creating reliable software systems.