Inför tenta Flashcards

Question

What is the principal role of architectural descriptions?

Answer 1

Architectural descriptions provide a basis for the development team to discuss and make informed decisions about the system's organization. They are crucial for communicating design intentions and decisions.

Answer 2

Informal diagrams are fast and easy to draw and share, making them effective for quickly communicating and iterating on architectural ideas during discussions

Answer 3

System decomposition involves breaking down architectural components into a set of finer-grain components, helping to manage complexity by detailing the subsystems and elements that compose them.

Answer 4

To minimize complexity, it is crucial to separate concerns, avoid functional duplication, and focus on clearly defined component interfaces, which enhance modularity and maintainability.

Answer 5

Web-based systems often utilize a layered structure, typically including a user interface layer, application-specific layers, and a database layer.

Answer 6

Distribution architecture defines how servers are organized within the system and how components are allocated across these servers, influencing system scalability and performance.

Answer 7

Multi-tier client-server and service-oriented architectures (SOA) are commonly used due to their flexibility, scalability, and ability to effectively separate concerns among different system layers.

Answer 8

Deciding on technologies such as databases and cloud platforms is a vital part of the architectural design process, as these decisions directly impact the capabilities, performance, and scalability of the system.

Answer 9

The cloud consists of numerous virtual servers available for rent. Users access these servers remotely over the Internet and pay based on the amount of server time used.

Answer 10

Virtualization is a technology that allows multiple server instances to run on the same physical computer, enabling the creation of isolated software instances for deployment in the cloud.

Answer 11

Virtual machines are replicas of physical servers that host their own operating system, technology stack, and applications, functioning as independent servers.

Answer 12

Containers are a lightweight virtualization technology that allows for rapid replication and deployment of server environments. Unlike virtual machines, all containers on a host share the same operating system. Docker is a prominent example of container technology.

Answer 13

In the cloud, "everything as a service" implies that various resources (computing, storage, applications) can be delivered over the Internet and rented rather than owned, shared with other users.

Answer 14

IaaS provides fundamental computing resources like servers, storage, and networking in the cloud, eliminating the need for physical servers.

Answer 15

PaaS involves using cloud platform services to automatically scale software applications in response to demand, simplifying many of the challenges associated with application scaling.

Answer 16

SaaS delivers application software directly to users over the Internet, offering benefits like reduced capital costs for users and easier deployment for vendors.

Answer 17

In multi-tenant systems, all users share the same database which can be adapted at runtime to meet individual needs. In multi-instance systems, each user has a separate database, offering enhanced isolation and customization.

Answer 18

Deciding on the cloud platform, and choosing between multi-tenant or multi-instance deployment models are critical architectural considerations that impact scalability, privacy, and cost.

Answer 19

Multi-tenant systems are a type of software architecture where a single instance of the software serves multiple customers, or tenants. All tenants share the same infrastructure and database, with the system dynamically adapting data and configuration to meet each tenant's specific needs. This setup maximizes resource efficiency and cost-effectiveness but may raise concerns about data privacy and customization.

Answer 20

Multi-instance systems are a type of software architecture where each customer, or tenant, has their own separate instance of the software and potentially their own dedicated database. This approach offers greater customization and isolation, which can enhance security and performance. However, it is generally more resource-intensive and expensive compared to multi-tenant systems.

Answer 21

A microservice is an independent, self-contained software component that operates in its own process and communicates with other microservices using lightweight protocols. This allows for high modularity and makes it easier for a microservice to be developed and scaled independently.

Answer 22

Yes, microservices in a system can be implemented using different programming languages and database technologies. This flexibility allows developers to use the best tool for each service's specific requirements.

Answer 23

Microservices should follow the single responsibility principle, meaning each microservice has one responsibility and can be developed, deployed, and scaled independently. This design facilitates easy changes and upgrades without affecting other components of the system.

Answer 24

Microservices architecture is ideal for cloud-based environments because each microservice can run in its own container, which promotes scalability and resilience. Containers facilitate the management and deployment of microservices, making them highly effective for dynamic cloud setups.

Answer 25

Architects in a microservices system must decide how to structure the system into microservices and determine the best methods for these services to communicate and coordinate. This includes choosing communication protocols and managing service dependencies and interactions.

Answer 26

Communication and coordination in microservices involve selecting protocols for microservice interaction, managing data sharing, deciding on the central coordination of services, and implementing effective failure management strategies

Answer 27

In microservice-based systems, the RESTful architectural style is commonly used where HTTP verbs—GET, POST, PUT, and DELETE—are mapped onto service operations. This style facilitates stateless communication and interaction using resources represented in formats like XML or JSON.

Answer 28

Continuous deployment is a process where new versions of a microservice are automatically deployed to production as soon as changes are made and validated through automated testing. This ensures that updates are rapidly available, maintaining high service quality and responsiveness.

Answer 29

With continuous deployment, it may be necessary to maintain multiple versions of microservices to allow rolling back to older versions if issues arise with newly deployed ones. This strategy helps in ensuring system stability and reliability.

Answer 30

Statelessness in microservices means that each request from a client to the server must contain all the information necessary to understand and complete the request, independent of any previous requests. This means the server does not need to remember the state of the application or the user's session. Statelessness helps improve scalability and reliability, as it allows requests to be handled by any available server instance.

Answer 31

The primary HTTP verbs used in RESTful services include: GET: Retrieve data from a server at the specified resource. POST: Send data to a server to create a new resource. PUT: Send data to a server to update an existing resource. DELETE: Remove an existing resource from the server. These verbs correspond to create, read, update, and delete (CRUD) operations in database management, allowing RESTful services to manage resources effectively.

Answer 32

The aim of program testing is to discover bugs and demonstrate that a program performs according to the expectations of its developers, ensuring both functionality and reliability.

Answer 33

The four types of testing relevant to software products are functional testing, user testing, load and performance testing, and security testing. Each type addresses different aspects of software quality and user experience.

Answer 34

Unit testing involves testing individual units of code, such as functions or class methods, to ensure they perform as intended. These units typically have a single responsibility, making them fundamental for verifying software behavior.

Answer 35

Feature testing focuses on individual system features, testing their functionality independently. System testing evaluates the entire system to check for unwanted interactions between features and with the system's environment, ensuring overall system integrity.

Answer 36

Equivalence partitioning involves dividing inputs into groups that are expected to elicit the same behavior from the software. Testing inputs at the boundaries of these partitions is an effective method for finding bugs.

Answer 37

User stories can serve as a foundation for deriving feature tests, providing real-world scenarios that the software should handle, thus guiding the creation of relevant and targeted tests.

Answer 38

Test automation is the practice of developing a set of executable tests that are run every time a change is made to the system. This helps in continuously verifying system functionality without manual intervention.

Answer 39

The structure of an automated unit test typically follows the arrange-action-assert pattern: set up the test parameters, execute the function or method, and then assert that the expected outcome has occurred.

Answer 40

Test-driven development (TDD) is an approach where executable tests are written before the actual code. Developers then write code that passes these tests, focusing on meeting predefined requirements before implementation.

Answer 41

Security testing may be risk-driven, focusing on identifying and mitigating potential security risks. It involves creating tests that reveal system vulnerabilities based on a list of known security concerns.

Answer 42

Program reviews are sessions where code is examined by other developers to assess quality and identify bugs. They are an effective supplement to automated testing, adding a human element to error detection.

Answer 43

Extreme Programming (XP) is an agile software development methodology aimed at improving software quality and responsiveness to changing customer requirements. It emphasizes frequent "releases" in short development cycles, which improves productivity and introduces checkpoints where new customer requirements can be adopted .

Answer 44

The Planning Game is an XP practice where developers and customers collaborate to define and prioritize system features. This iterative planning approach helps manage scope and requirements in a flexible, responsive manner .

Answer 45

Small Releases is an XP practice involving frequent releases of the software in small, incremental updates. This approach allows for quick feedback from customers and continuous improvement of the product .

Answer 46

In XP, Metaphor serves as a guide for the development process and system design. It helps all team members understand how parts of the software interact and ensures coherence in the system’s architecture .

Answer 47

Simple Design in XP emphasizes creating software that is simple enough to meet the current requirements and no more. This minimizes waste, reduces complexity, and facilitates changes and maintenance .

Answer 48

XP integrates testing throughout the development process. Developers write tests before coding (test-driven development), and all code must pass these tests before it is considered complete. Continuous testing ensures quality and reduces bugs .

Answer 49

Refactoring in XP involves modifying the code to improve its structure and readability without changing its external behavior. This practice is crucial for maintaining simplicity and managing technical debt over time .

Answer 50

Pair Programming is an XP practice where two developers work together at one workstation; one writes the code while the other reviews it as it is written. This collaboration enhances code quality and facilitates knowledge sharing .

Answer 51

Collective Ownership in XP means that any developer can change any part of the project’s code at any time. This approach encourages responsibility and improves the software’s overall quality as more developers scrutinize and refine the code .

Answer 52

Continuous Integration in XP involves integrating and building the software frequently, often multiple times a day, to detect integration errors as quickly as possible. This practice helps maintain a high level of software health and readiness .

Answer 53

Sustainable Pace (formerly known as the 40-hour week) is an XP principle that encourages teams to work at a consistent and sustainable pace to avoid burnout and maintain productivity over the long term .

Answer 54

The On-Site Customer is an XP practice where a real customer is present full-time with the XP team to answer questions, resolve uncertainties, and provide quick feedback. This presence ensures that development aligns closely with customer needs and priorities .

Answer 55

Pair Programming is a core XP practice where two developers work together at one workstation. One, the "driver," writes the code, while the other, the "observer" or "navigator," reviews each line of code as it is typed in. The roles can switch frequently. This collaboration not only improves code quality but also facilitates knowledge sharing and reduces the likelihood of complex bugs making it into production .

Answer 56

Test-Driven Development is an XP practice where tests are written before the actual code. Developers first write failing unit tests that define required new functionality, then they write code to pass those tests, and finally refactor the code to meet standards of cleanliness. This ensures that all written code has been tested from the start, leading to fewer bugs and encouraging simple designs .

Answer 57

Continuous Integration in XP involves integrating and testing code changes multiple times a day. Every time code is integrated, it is automatically built and tested, and if the build or tests fail, it is fixed immediately. This practice helps keep the code base stable and allows XP teams to develop faster with more confidence .

Answer 58

Refactoring is the XP practice of altering the internal structure of the code to make it easier to understand and cheaper to modify without changing its observable behavior. This ongoing process of code improvement helps to maintain software quality and adaptability over time, facilitating the addition of new features without degrading system performance .

Answer 59

Regression testing is a type of software testing that verifies that recent code changes have not adversely affected existing functionalities. It involves re-running previously passed tests on updated code to ensure that past functions still operate as expected after modifications. This practice is crucial for maintaining the stability and integrity of the software as it evolves over time.

Answer 60

Performance is a critical issue in software architecture design, requiring architects to ensure that the system meets the required response times and throughput rates under various operational conditions .

Answer 61

Security is paramount in software architecture as the design must safeguard against potential threats and vulnerabilities, ensuring data integrity and system protection against unauthorized access .

Answer 62

Scalability is crucial in software architecture to ensure the system can handle increased loads effectively without performance degradation, accommodating growth in user numbers and data volume .

Answer 63

Robustness in software architecture design ensures the system can cope with errors during execution and adverse conditions without failing, maintaining reliability and stability

Answer 64

Flexibility is essential for allowing future modifications and adaptations of the system with minimal disruption, supporting the integration of new features and technologies as requirements evolve .

Answer 65

Container-based virtualization, such as Docker, allows multiple applications to run on the same operating system (OS) but in isolated spaces called containers. These containers share the OS kernel, start up faster, and use fewer resources compared to virtual servers. Virtual servers, or virtual machines (VMs), each run their own OS instance on top of the physical server's hardware using a hypervisor. This provides complete isolation at the OS level, better security, and allows for different operating systems to coexist on the same physical hardware, but at the cost of greater resource consumption and slower startup times

Answer 66

Microservices are designed to be scalable, meaning each service can be independently scaled to meet demand without affecting the operation of other services in the system .

Answer 67

Microservices are maintainable because they are small and focused on doing one thing well, which simplifies understanding, testing, and updating the service .

Answer 68

In microservices architecture, each service manages its own database, rather than relying on a single database for the entire application. This approach increases resilience and ensures that services are loosely coupled .

Answer 69

Microservices are designed to isolate failures, which means if one service fails, it doesn't necessarily bring down other parts of the application. This characteristic enhances the overall reliability of the application .