15 to 30 random questions in 15 to 30 minutes, by the level you choose: processes, scheduling, synchronization, deadlocks, memory and files. After you submit you get your score, your strong and weak topics, and the right answer with an explanation for every question.
Want to revise first? Read the Operating Systems interview questions and answers.
The test covers 12 topics across three levels. Each attempt picks 15 to 30 questions at random, by the level you choose, so every attempt is different.
One question from each level, the way they appear in the test. A new set comes on the 1st of every month. Try it, then open the answer.
Answer: Contiguous allocation. With contiguous allocation a file is one run of blocks, so block i is at start + i: very fast. But files of different sizes leave holes between them, and growing a file may mean moving it. Linked and indexed schemes avoid this.
Answer: The thread may wake spuriously, or the state may change before it gets the lock. POSIX allows spurious wakeups, and with signal-and-continue semantics another thread can take the item before the woken thread gets the mutex. Rechecking in a loop makes the code correct in both cases; an if can act on a false condition.
Answer: A vDSO page mapped into each process lets it read the kernel's clock data in user mode. The vDSO (virtual dynamic shared object) is a small shared library the kernel maps into every process. It reads a time data page that the kernel keeps up to date plus the CPU time stamp counter, so common time calls avoid the cost of a real system call.
Take the full Operating Systems mock test: 15 to 30 questions and 15 to 30 minutes, by level.
A question counts as right only when you pick exactly the right option, or all the right options where it says so; a question left blank counts as wrong. Your score is the share of the test's questions you got right (15 to 30, by level). The result also scores every topic, so you know what to revise before the interview.
Yes. The Operating Systems mock test is free. You need a free CoreHRx Jobs account to start it, so your score and the topics to work on are saved.
It depends on the level: Easy has 15 questions in 15 minutes, Medium has 20 questions in 20 minutes, Hard has 30 questions in 30 minutes. They are multiple-choice questions picked at random from a larger bank of Operating Systems questions at your level, so every attempt is different.
The questions cover CPU Scheduling, Virtual Memory, Process Synchronization, Processes and Threads, Linux and Unix Concepts, Paging and Segmentation, Deadlocks, File Systems, OS Basics and System Calls, Disk Scheduling, Memory Management, I/O and Interrupts. Your result shows how you did in each topic.
Easy: Processes, threads, system calls and scheduling basics. Medium: Scheduling problems, synchronization, deadlocks and paging. Hard: Virtual memory, page replacement and tricky concurrency, for top scores. Start with Easy and move up.
Only your best Operating Systems score, and only when it is 60% or more. It shows on the job applications you send on CoreHRx. Lower scores stay private.
Yes, up to 10 tests a day. Each attempt picks questions you have not seen recently first.
