Definition and Objectives of Computer Application Architecture

Software architecture, or architecture of computer applications, is defined as the set of necessary structures for designing a system or an application. These structures include software components, relationships between these components, and patterns that guide their composition. In simpler terms, we could say that software architecture is like a blueprint for constructing a house, but in this case, that house is a computer application.

The objectives of software architecture can be summarized as the creation of a coherent system where various components work together to produce desired results. However, beyond that simplicity, there are several specific objectives that guide the conception and construction of software architecture.

• Facilitating communication among stakeholders: Software architecture helps different stakeholders (developers, project managers, end users, etc.) understand and communicate about the system.
• Enabling early decision-making: High-level decisions about the system are made during the design of the architecture, which can have a significant impact on the final outcome.
• Providing a basis for reuse of design elements and code: Architectural patterns, components, and design decisions can be reused across different projects, saving time and effort.
• Managing system complexity: Breaking down a system into manageable components (modules) helps developers understand, develop, and test different parts more effectively.

Throughout this chapter, we will delve into these objectives and how they manifest in different facets of software architecture design, including architecture planning, database and infrastructure design, identifying specific goals such as reuse, modularity, and flexibility, and the crucial role played by software architects in this process.

Software architecture, in simple terms, can be considered as the skeleton of a computer system. It is the structure that organizes the system into components, defines the interfaces through which these components interact, and establishes the constraints under which the system is developed and evolves. But beyond being just a skeleton, software architecture is the blueprint that guides developers in building the system, providing coherence, stability, and efficiency.

The importance of software architecture lies in several factors:

• Communication and coordination: By providing a structural design of the system, architecture facilitates the overall understanding of the system, serving as a means of communication among all stakeholders, including developers, project managers, users, and anyone else involved in the system.
• Complexity management: Without a well-defined architecture, a complex system can become unmanageable. Architecture breaks down the system into smaller, manageable components, making it easier to develop, test, and maintain the system.
• Software quality: A good architecture can significantly improve the quality of software, ensuring that the system is robust, scalable, maintainable, and efficient.
• Resource savings: By facilitating component reuse and standardization of designs and patterns, software architecture can save a lot of time and effort throughout the software development lifecycle.

The design and planning of software architecture are the initial and essential stages in the development of any computer system. This process involves conceiving a structured vision of how the different parts of the system will be organized and function to meet the specified requirements.

The planning of architecture begins with gathering system requirements. In this step, it is determined what the system needs to do, what functions it should have, and how it will interact with its users or other systems. Based on these requirements, software architects must consider various aspects before designing the architecture. These include, but are not limited to, selecting appropriate technology, identifying design patterns to be used, coding standards, and testing policies.

Once these criteria are established, the architecture design begins, which is a high-level representation of the system. The design includes defining the major components or modules of the software, specifying the interfaces through which these components will interact, and describing the interactions and data flows between the components.

The design and planning of architecture are not static tasks; they require constant review and adjustments as the project progresses. It is important to note that architecture design is a creative activity that requires technical skills, experience, and a solid understanding of business and system requirements.

The importance of effective planning and design lies in their influence on all subsequent stages of software development. A good architecture will provide a solid framework for development, facilitate decision-making during the implementation process, and serve as a guide for maintenance and future system updates.

In any software system, database design and infrastructure are vital components that play a central role in the efficiency, reliability, and robustness of the system.

Database design involves structuring the data in a way that meets the application's needs, optimizes performance, and ensures data integrity and security. This process includes defining tables, relationships, indexes, and stored procedures that will be used to manage the data. The choice between different database models, such as relational, document, key-value, among others, will largely depend on the specific requirements of the application.

Database design must consider aspects such as data normalization to avoid redundancy, defining primary and foreign keys to maintain data consistency, and implementing security mechanisms to protect the data. Additionally, aspects like scalability, performance, and availability of the database should be taken into account.

On the other hand, infrastructure refers to the technological environment that supports the application. It includes hardware, the operating system, web servers, application servers, and any other component necessary to run the application. The design of the infrastructure should ensure that the application can handle the expected workload, is scalable to accommodate future growth, and has high availability and fault tolerance.

The infrastructure can be hosted locally, in a data center, or in the cloud. Each option has its own advantages and disadvantages that should be considered based on the system requirements. Infrastructure as code (IaC) and cloud computing have enabled software architects to define and manage infrastructure more efficiently, securely, and at scale.

Identifying the objectives of software architecture is a critical step in the design and planning phase. The objectives guide design decisions and help define the priorities and constraints of the system. Each established objective will have an impact on the final design and performance of the system, so it is crucial that they are carefully considered and defined.

Here are some common objectives in software architecture:

• Performance: The system should be able to handle a certain workload volume within acceptable parameters. This may include aspects such as response speed, latency, and performance under load.
• Security: Protecting the data and functionality of the system against unauthorized access and other security threats is a key objective for any software architecture.
• Scalability: The system should be able to handle an increase in workload without negatively affecting performance or functionality. This may involve horizontal scalability (adding more machines) or vertical scalability (increasing the capacity of an existing machine).
• Availability: In many cases, it is crucial that the system is available for use at all times or during a very high percentage of time.
• Maintainability: The system should be easy to modify to fix bugs, improve performance, or adapt to new requirements.
• Reusability, Modularity, and Flexibility: These objectives refer to the ability to reuse software components, organize the system into independent modules, and adapt to changes with minimal effort.

It is important to note that these objectives often can conflict with each other. For example, improving performance may require compromising maintainability, or increasing security may affect ease of use. Therefore, part of the work of a software architect is to balance these objectives to find the best solution for a particular set of requirements and constraints.

The software architect plays an essential role in any software development project. They are often compared to the architect of a building, as they are responsible for designing the high-level "structure" of a system and ensuring that all elements fit together correctly to meet project objectives.

Here are some of the common responsibilities of a software architect:

• Architecture Design: As the name suggests, one of the key responsibilities of a software architect is designing the system architecture. This includes defining the overall structure of the system, identifying key components and their interrelationships, and choosing appropriate technologies and architectural patterns.
• Technical Decision-Making: Software architects are responsible for making important technical decisions, such as choosing technologies and platforms, defining coding standards and development practices, and identifying strategies for aspects like security, performance, and scalability.
• Quality Management: Software architects play a crucial role in ensuring quality assurance, making sure the software meets established quality standards and working to continuously improve software quality over time.
• Stakeholder Communication: Software architects must effectively communicate with all stakeholders, including developers, project managers, end-users, and clients. This may involve presenting architectural designs, explaining technical decisions, and gathering feedback and requirements.
• Change Management: Software architects need to manage changes in requirements and the project environment, being able to adapt the system architecture accordingly.
• Mentoring and Leadership: Many software architects also take on a leadership role, guiding and advising members of the development team and promoting best software development practices.