The long interview day is nearing its end. Googamazbook got the best and the worst out of you (well, neither of those, but I’m trying to put some literature in here); the last interviewer comes in, smiles condescendently and greets you with:
Time for the easy interview, heh?
Yes, you have all the reasons to be concerned and feel you’re just one step away from failure (yes, why didn’t you spend the day by the pool in the basement of the many stars hotel they got you a room in for the interview?). But without further ado, the questions start pouring in:
How do you figure out if a process is CPU bound or I/O bound?
Tricky! Let’s not jump to the conclusion. There are 2 variables here, this means we have 4 possibilities:
You’re in a tiny room at Googamazbook and the interviewer comes in, says hi (if you’re lucky), presents themselves (they’re really into doing you a favor) and then starts asking questions. The easy one comes first:
What happens when you run telnet www.brainware.ro 80 ? Please go on through all the layers.
Warmed up from the systems interview, you start talking about /etc/hosts and /etc/resolv.conf: name resolution and then the actual connection to the http port. If your knowledge stops here, please do go on reading this text. Or just do go on, maybe I forgot something.
1. Name Resolution
The name resolution protocol is performed by sending an UDP packet to each resolver found in /etc/resolv.conf. The UDP packet has a small header containing:
You have the shared document open and the phone rings. The interviewer, at the other end of the line, starts with a thick accent:
– What does ls * do?
You cannot believe your ears: it sounds easy. Really easy. So you answer in the line of “it lists all the files in the current directory”. The interviewer follows up with one or 2 questions on how it really works and you answer about the star being passed as a parameter to ls and how the binary interprets it in some way that it gets the entire directory walked over and its contents listed. Simple!