Greetings to all, I am Jay Gorakhiya and this blog is about my MS Interview experience. Below is my GATE result details
Rank : 229
Score: 757
Category : GEN
First of all, with this score one can get admission in MTech in IIT G / KGP / R but still I had applied for MS (Research) in IIT Madras , Bombay and Delhi and had given interviews of Bombay and Madras.
This year (2023), IIT Madras had 2 rounds of Interviews, First round ( shortlisting criteria was GATE score ) was like a common round where interview was on one of the topics from Discrete Maths OR C programming ( or Programming )in general. Students were shortlisted for round2 on the basis of performance in round1. Second round was panel specific round (3 panels; A. Theoritical Computer Science, B. Computer Systems, C. Intelligent Systems ) and students shortlisted from round1 were given a google form to fill their preference of panels. Interview in first 2 panels of preference was to be conducted. Final selection was made on the basis of performance in round2. Both rounds were online through Google Meet.
=================================== ROUND 1 ===================================
There was only 1 professor who interviewed me in round 1. The prof. was very nice and kind to me. He asked my name and from where i was and how was i feeling etc. Overall, he was very polite and quiet and made me feel comfortable before starting the interview. Interview went like this :
Prof. : What is your choice of subject? between Discrete Maths & Programming.
Me : As such there’s no preference but I’ll go with Programming.
Prof. : Write a program that tells whether a number is perfect number or not? (He then shared a link of an editor to write the code, which he could also see without me sharing the screen.)
Me : what is the definition of a perfect number? (I asked for definition, even though i knew it)
Prof. : a number is a perfect number if sum of its divisors (less than the number) is equal to the number itself.
Me : Okay (then I started writing the code, which was fairly simple)
( always speak aloud what you are thinking and what code you are writing while writing the code to interviewer )
Prof. : What is the Time Complexity of the Code?
Me : O(N) ( as the code had linear time complexity)
Prof. : Can you reduce the Number of Comparisions? or Can you eliminate redundant Comparisions??
Me : ( I gave some ans which was not 100% correct, was just beating around the bush )
( Actual ans was, we can run for loop upto n/2 instead of running it upto n as no divisor of n is greater than n/2 , which i realized after the interview 🙂 )
He then asked me some Questions on basic data structuers like arrays.
Prof. : You know array data structuers, right?
Me : Yes sir.
Prof. : What is the time complexity to find an element from the array?
Me : there are 2 algos, if linear search if the array is not sorted O(n) and binary search if the array is sorted O(logn).
Prof. : We do not know, if it is sorted or not i.e not neccasarily sorted array then what will you use?
Me : Linear Search.
Prof. : Can you decrease number of comparisons done in linear search while TC remains same O(N)?
Me : (first i explained the normal code of linear search )…( thought for some seconds, then he reframed the question )
Prof. : There are 2 key comparisons; first is whether we have reached array end or not? and second whether the current element is the element we are looking for? Can you eliminate any one of the comparision??
Me : we cannot eliminate second comparison because if we removed it then we wont be able to ‘search’ for a particular element, so we can try to eliminate first one. ( then i was thinking and then prof gave me a hint)
Prof. : What if we can change the input a little? What if we add the element which we are looking for at the end of the array then can we eliminate end of array comparison?
Me : (I gave some ans here and there but they were not correct)
Finally, professor told me to think on the question afterwards and my round1 interview was over. Interview was around 10-15 mins. Round 1 results were out by the night and i was shortlisted for round 2. I had selected panel B (Computer Systems) and panel C (Intelligent Systems) but gave interview only for panel B as i was more confident in that.
=================================== ROUND 2 ===================================
In round2, there were 2 professors but only one of them asked questions. My choice of subject in computer systems panel was Operating Systems. Again, the professor was very nice to me, made me feel comfortable. I don’t remember all the questions exactly, so i am listing down questions which i remember.
- What different types of OS do you know and have used?
(from there he jumped to uniprocessor multiprogramming OS ; as in GATE syllabus)
- What is scheduling? What are the CPU scheduling algorithms you know?
- What is context switch? How does it happen? (asked me to explain step by step what happens during a context switch)
He went to ask in much detail like:
- who loads and save PCBs of the processes?
- before the context switch a user process is runnning on processor, so how does OS takes control of the processor during context switch? ans : through interrupt.
- who / which component interrupts the processor? etc
(from there he jumped to Interrupts and System Calls)
- What is ISR, vectored interrupt? How does the Computer know which routine is for which interrupt?
- What is System call? Difference between an interrupt and a system call?
- Do we need an interrupt for executing a system call? etc
From there on the prof. began I got a bit confused and afterwards he ended my interview. Interview went for around 15-20 minutes. At last the prof. gave me a remark that first part of my answers were good (scheduling and context switch ones), that made me feel good that IIT professor thinks my ans is good 😄. After few days, results were out and I was selected for MS (Research) in computer systems at IIT Madras. I eventually rejected the offer as I finally accepted MTech RA IITB.
So, this was my interview experience. Hope you find it helpful. Kudos to you if you’ve reached this far reading as the blog was a bit long.
ALL THE BEST.
