SDIs

SDI introduction

What are SDIs

The purpose of a SDI is to assess a candidate's ability to design and understand complex systems. It's a crucial part of the hiring process for roles that involve system architecture and engineering, such as software engineers, system architects, and DevOps engineers. Here's a breakdown of what these interviews aim to evaluate:

Evaluating Technical Proficiency

• Design Skills
  • Assessing the ability to design a scalable, efficient, and robust system architecture.
• Problem-solving Skills
  • Gauging how you approach and solve complex, open-ended problems.
• Technical Knowledge
  • Understanding your familiarity with various technologies, databases, frameworks, and protocols.

Understanding Approach and Methodology

• Requirements Gathering
  • Your ability to understand and outline the requirements of a system before diving into the solution.
• Balancing Trade-offs
  • How you balance various trade-offs in system design, such as between scalability and cost, or performance and reliability.
• Decision-making Process
  • Evaluating your reasoning behind choosing certain technologies or architectures over others.

Testing Soft Skills

• Communication
  • Your ability to clearly articulate your thought process and design choices.
• Collaboration
  • Assessing how you interact with interviewers, which can mimic real-life collaboration with team members.
• Adaptability
  • Your response to new information or feedback during the interview, reflecting your ability to adapt in real-world projects.

Real-world Application

• Practicality
  • Ensuring that your designs can be practically implemented and are not just theoretical.
• Scalability and Performance
  • Your understanding of how the system would perform under real-world constraints and loads.

Innovation and Creativity

• Creative Thinking
  • Looking for innovative solutions and ideas that showcase your ability to think outside the box.
• Future-Proofing
  • How you design systems with future growth, maintenance, and potential challenges in mind.

The SDI is a critical tool for employers to assess not just your technical abilities, but also your problem-solving approach, communication skills, and overall fit for roles that require designing and working with large-scale systems. It's a comprehensive evaluation of how you would handle real-life challenges in system architecture and engineering.

What SDIs are not about

• It’s not about getting the perfect answer. In fact, there often isn’t one “correct” solution in system design.
• It’s not a test of memorization. While familiarity with certain tools and technologies is helpful, understanding the concepts is more important.

Functional vs non-functional requirements

In the context of SDIs, understanding functional and non-functional requirements is key to showcasing your ability to design a system that meets both the specific actions it should perform and how it should perform them.

Functional requirements

These are the requirements that define what a system is supposed to do. They describe the various functions that the system must perform.

Examples

• A user authentication system must validate user credentials and provide access levels.
• An e-commerce website should allow users to browse products, add them to a cart, and complete purchases.
• A report generation system must collect data, process it, and generate timely reports.

Importance

• Demonstrates Understanding of Core Features: Shows you know what the system needs to do to satisfy its primary objectives.
• Basis for System Design: Functional requirements often form the backbone of your system design.

Non-functional requirements

These requirements describe how the system performs a task, rather than what tasks it performs. They are related to the quality attributes of the system.

Examples

• Scalability: The system should handle growth in users or data.
• Performance: The system should process transactions within a specified time.
• Availability: The system should be up and running a defined percentage of time.
• Security: The system must protect sensitive data and resist unauthorized access.

Importance

• Showcases Depth of Design Knowledge: Demonstrates your understanding of the broader implications of system design.
• Highlights System Robustness and Quality: Reflects how well your system design can meet real-world constraints and user expectations.

Integrating both in SDIs

• Scenario-Based Discussions
  • When presented with a scenario, identify both the functional (what the system should do) and non-functional (how the system should do it) requirements.
• Balancing Act
  • Exhibit your ability to balance both types of requirements, showing that you can design a system that not only meets its functional goals but also performs effectively, securely, and reliably.

When you're in a SDI, here's how you can handle these requirements:

• Clarify Requirements

  • Start by asking questions to understand both functional and non-functional requirements. Interviewers often leave these vague to see if you'll probe for more details.

• Prioritize

  • Not all requirements are equally important. Identify which ones are critical for the system’s success.

• Trade-offs

  • Discuss trade-offs related to different architectural decisions, especially concerning non-functional requirements. For example, a system highly optimized for read operations might have slower write operations.

• Use Real-World Examples

  • If you can, relate your points to real-world systems or your past experiences. This shows practical understanding.

• Balance

  • Ensure you're not focusing too much on one type of requirement over the other. A well-rounded approach is often necessary.

Remember, in SDIs, interviewers are often interested in seeing how you think and approach problems, not just your final solution. Demonstrating a clear understanding of both functional and non-functional requirements is key to showing your comprehensive knowledge in system design.

Things to avoid in SDIs

In a SDI, while it's important to showcase your skills and knowledge, it's equally crucial to be aware of common pitfalls. Avoiding these mistakes can greatly improve your chances of success. Here are some key "don'ts" for a SDI:

Don't ignore the requirements

• Neglecting to Clarify
  • Failing to ask questions or clarify requirements can lead to a design that misses the mark.
• Oversimplifying the Problem
  • Don’t oversimplify the problem or ignore the complexities involved.

Don't dive into details too soon

• Rushing into Low-Level Details
  • Starting with low-level details before establishing the high-level design can make your solution seem disjointed.
• Losing Sight of the Big Picture
  • Focus first on the overall architecture and how different components interact.

Don't stick rigidly to one idea

• Being Inflexible
  • Being too rigid with your initial idea can prevent you from considering better alternatives.
• Ignoring Interviewer’s Hints
  • The interviewer might provide hints or feedback; not adapting your design accordingly can be seen as a lack of collaboration or adaptability.

Don't overthink trade-offs

• Ignoring Trade-offs
  • Every design decision has trade-offs. Not discussing these can show a lack of depth in your understanding.
• Failing to Justify Decisions
  • Be prepared to explain why you chose one approach over another.

Don't neglect non-functional requirements

• Overlooking Scalability, Reliability, etc.
  • Focusing solely on functional aspects and neglecting non-functional requirements like scalability and reliability is a common mistake.
• Not Considering System Constraints
  • Real-world constraints such as cost, time, and existing technology stack should be considered.

Don't under-communicate

• Poor Explanation
  • Failing to clearly articulate your thoughts can leave interviewers unsure about your understanding and approach.
• Not Engaging the Interviewer
  • This is a dialogue, not a monologue. Engage with the interviewer, ask questions, and be receptive to feedback.

Don't be overconfident or arrogant

• Overconfidence
  • Being overly confident can lead to dismissing valuable feedback or overlooking key aspects of the problem.
• Not Acknowledging What You Don’t Know
  • It’s okay not to know everything. Being open about areas you are unsure of is better than providing incorrect information.

A SDI is not just about getting the right answer. It's about demonstrating your problem-solving approach, your ability to adapt, and how you communicate and collaborate. Avoiding these pitfalls can help you present yourself as a well-rounded candidate capable of handling the complexities of real-world system design.