TOPIC
Operating systems
These are the same questions found in the library, grouped here by the capability each one mainly examines.
12 questions
A · Professional problem solving and implementation12
- Two jobs run fine alone but occasionally hang when run together. What conditions must hold for a deadlock, and how would you confirm that is the cause?
- A long-running process keeps using more memory, while object counts in heap snapshots fluctuate. How would you use evidence to distinguish a true leak, intentional cache retention, fragmentation, or growth in native memory?
- Your service handles requests with threads and a colleague proposes processes instead. What would you compare, and when would you push back?
- A service increases its worker threads from 16 to 256, but throughput does not improve and CPU use rises. How could context switching contribute, and what evidence would you use to verify it?
- A service’s resident memory is stable, but major page faults, disk I/O, and tail latency rise together. How would you distinguish changes in the working set, mapping behavior, memory pressure, and application access patterns?
- Two processes both access address 0x1000. Why do they usually not read or write the same physical memory? Explain the address translation and operating-system responsibilities.
- After deployment on a multi-socket machine, threads move across NUMA nodes and memory latency varies. How would you investigate using CPU affinity, memory placement, and scheduling behavior?
- After certificate rotation, short connections work, but some clients fail a handshake when reconnecting or resuming after a long-lived connection closes. How would you distinguish certificate-chain, resumption, connection-pool, and client-cache effects?
- When a mobile device switches from Wi-Fi to cellular, some HTTP/3 requests fail while the session still appears online. How would you investigate path migration, timeouts, and middlebox behavior?
- A program writes a data file before updating its index, but after a power loss the index points to incomplete content. How would you analyze write ordering, flush semantics, and recovery?
- A function appears read-only under multithreading, but a formatter it calls uses a shared internal buffer and occasionally mixes results. How would you distinguish thread safety, reentrancy, and statelessness, and decide where to fix the issue?
- CPU averages 35%, but the request queue keeps growing and threads wait on external I/O. How would you identify the real capacity bottleneck?
No questions in this section match your target. ·