Processes and signals, file descriptors, DNS and TLS, and debugging connectivity from first principles.
5 questions in DevOps & Cloud.
Work up the layers and let each command eliminate a class of cause: resolve the name, check the route, see whether anything is listening, then decide from the failure mode whether packets are being refused, silently dropped, or answered by something that never replies.
df and du disagree because df reads filesystem block allocation while du walks visible directory entries. Deleted-but-open files, inode exhaustion, hidden files under mounts and reserved blocks are the usual causes. Use this LINUX answer to show the decision, trade-off, and evidence rather than a memorised definition. It also connects filesystems to the point an interviewer is testing.
Assess the candidate's capability to design sophisticated DVFS algorithms and power management strategies for severely energy-constrained IoT devices operating on harvested energy. Use this hardware answer to show the decision, trade-off, and evidence rather than a memorised definition. It also connects power management to the point an interviewer is testing.
Separate the layers that can fail together: routing reachability, name resolution, identity and physical access. Then build an access path that shares none of them, keep controls failing static rather than closed, and rehearse the emergency path often enough that it is known to work.
Evaluate the integration of kernel-bypass techniques to handle millions of simultaneous connections and minimise CPU overhead in MMO architectures.