Systems Engineer, Prime Air

Amazon

You are given an array of servers represented by their processing power. You want to join consecutive servers together to form larger, more powerful servers. You can only join server i with server i+1 if the processing power of server i+1 is strictly greater than the processing power of server i. This joining process can cascade, meaning that if you join i and i+1, and the new combined processing power is less than i+2, you can then join the combined server with i+2, and so on. The goal is to maximize the number of these larger servers. For example: Consider the array [1, 2, 3, 4, 5]. You can join 1 and 2 to form 3. Then you can join 3 and 3 to form 6. Then you can join 6 and 4 to form 10. Finally, you can join 10 and 5 to form 15, resulting in one server with processing power 15. Consider the array [5, 4, 3, 2, 1]. You cannot join any servers because the processing power is always decreasing. Consider the array [1, 3, 2, 4, 1, 5]. You can join 1 and 3 to get 4. You cannot join 4 and 2. You can join 2 and 4 to get 6. You cannot join 6 and 1. You can join 1 and 5 to get 6. The final servers will be [4, 6, 6]. Write a function that takes an array of integers representing server processing powers and returns the final array of server processing powers after performing all possible joins.

Amazon

Let's delve into the fascinating world of operating systems. Imagine you're designing a new OS, and you need to implement a memory management system. Discuss the following: Virtual Memory: Explain the concept of virtual memory. How does it help in managing memory efficiently, especially when dealing with processes that require more memory than physically available? Provide a specific example of a scenario where virtual memory shines, such as running multiple large applications concurrently on a system with limited RAM. What are the benefits and drawbacks of using virtual memory? Specifically discuss the performance overhead associated with page faults. Page Replacement Algorithms: Describe different page replacement algorithms (e.g., FIFO, LRU, Optimal). For each algorithm, provide a step-by-step example using a reference string of page accesses (e.g., 1, 2, 3, 4, 1, 2, 5, 1, 2, 3). Calculate the number of page faults for each algorithm. Discuss the trade-offs between the complexity of the algorithm and its performance in terms of minimizing page faults. Explain a situation where FIFO would perform worse than LRU, and vice versa. Memory Fragmentation: Explain internal and external fragmentation. Give examples for each. What are the causes of each type of fragmentation? What strategies can be used to mitigate memory fragmentation (e.g., compaction, paging, segmentation)? Discuss the advantages and disadvantages of each strategy. Protection and Security: How does the OS protect memory from unauthorized access by different processes? Explain the role of memory protection mechanisms like base and limit registers, and page table entries (PTEs) with protection bits. Describe a scenario where a process attempts to access memory outside of its allocated region, and explain how the OS would handle this situation to prevent security breaches. How can techniques like Address Space Layout Randomization (ASLR) further enhance memory security?

Amazon

Tell me about yourself. To help me understand your background, please structure your response by including the following: A brief overview of your educational background: Where did you go to school, what did you study, and what were your key areas of focus or specializations? A summary of your professional experience: Walk me through your previous roles, highlighting the companies you worked for, your responsibilities, and the significant projects you contributed to. Be sure to mention any accomplishments or quantifiable results you achieved. Skills and areas of expertise: What are your strongest technical skills and areas of expertise? Provide specific examples of how you've applied these skills in previous projects or roles. For instance, if you're proficient in Python, describe a project where you used Python to solve a complex problem. Your motivations and interests: What are you passionate about in the field of technology, and what motivates you to pursue a career in this area? What specific aspects of software engineering or your chosen field do you find most exciting or rewarding? Your career goals: Where do you see yourself in the next 3-5 years? What are your short-term and long-term career aspirations, and how does this role align with your overall goals? Are you looking to specialize in a particular area, take on leadership responsibilities, or make a significant impact in a specific industry? By providing this structured overview, I hope to gain a better understanding of your background, skills, and aspirations, and how they align with the goals and requirements of this position.