System Calls Fundamentals Questions
Core OS-level concepts covering system call interfaces and conventions, examples such as fork, exec, opendir, and stat, kernel-user space interactions, process lifecycle, file I/O, memory management primitives, and basic concurrency primitives in systems programming.
MediumTechnical
0 practiced
Your service is making ~100k syscalls/sec and consuming high user CPU. As an SRE, outline how to profile which syscalls dominate (tools and commands, e.g., perf, strace, sysdig, bpftrace), and propose concrete changes to reduce syscall overhead such as batching, syscall reduction, and using zero-copy APIs. For each proposed change, list trade-offs and how to validate the improvement in production safely.
EasyTechnical
0 practiced
Discuss how errno is set by system calls on failure, the thread-safety concerns of strerror(3) vs strerror_r(3), and best practices for formatting diagnostic messages in SRE-run services (include syscall name, errno numeric value, and human-readable text). Also cover minimal-impact ways to collect such errors in high-throughput paths.
EasyTechnical
0 practiced
Explain the difference between a user-space function call and a system call on Linux/x86-64. Describe what happens during the kernel-user boundary transition: which instruction(s) are used, the register calling convention for arguments/return, how context changes, and why system calls are more expensive than normal calls. As an SRE, explain why syscall overhead matters when designing low-latency/high-throughput services and which measurements you would collect to validate impact.
MediumTechnical
0 practiced
Explain the semantics of O_APPEND on Linux. Is write(2) atomic for multiple processes appending to the same file? Under what conditions does the kernel guarantee atomicity for appends, and what are the implications for multi-process logging? Provide recommendations for safe concurrent appends.
EasyTechnical
0 practiced
List the POSIX functions that are async-signal-safe and explain why that property matters when implementing signal handlers. Give concrete SRE examples of what is safe to do in a handler (e.g., set a volatile sig_atomic_t flag, write a byte to a pipe) and what is dangerous (e.g., calling malloc, printf), and explain how to integrate signal handling safely into an event-driven server.
Unlock Full Question Bank
Get access to hundreds of System Calls Fundamentals interview questions and detailed answers.
Sign in to ContinueJoin thousands of developers preparing for their dream job.