Hewlett Packard Enterprise | HPE Interview Question

1-1 Face to face interview. Was asked questions from DBMS. Difference between lock and semaphore. Was asked to write a code: A variation of merge sort (don’t remember the exact question). Discussed in-depth deadlocks. Discussion about volatile storage, its need, what would happen if it was not present. What is its need if I have 24hrs of power on? Asked about big O complexity.i++ vs ++i.Which is faster and why.