Most viewed posts in Interview Experience

BLOG INDEX

• Interview Details, Experience & Result (to get comfortable with environment)

• Takeaways From Interview Experience (to learn from experience)

• Information Related to SysAdmin Position (know about your RA position)

• My views on SysAdmin RA and TA

• Why I have chosen SysAdmin RA (what is your reason for chosing)

----------------------------------Interview Details, Experience & Result

It was round 1 for top candidates applied and round 2 was after 5th round of COAP for remaining candidates (based on seats vacant in round 1 and does not accepted any offer)

Date: 22-June-2020 (online using Google meet) (due to COVID-19)

Position: CSE Sysadmin RA (6)

Duration of interview was 25-35 minutes. (after 1 pm)

There was a waiting lounge using another Google meet. I was waiting at position 8th in panel 1. (around 10-9 members in both panels)

There were about 4-5 panelists including one professor (Prof. Varsha Apte), Sysadmin head (Mr. Ranjith Kumar) and current sysadmin RA.

(I will try to frame questions as exactly as they said, and will give gist of answers I told, as thinking and presentation skills are different for different persons)

---------------------------------------------

I1(Varsha Apte): Say Your Name, Form Id, and Declaration that nobody is helping me in this interview, and haven’t selected any offer.

[Told]

I1: Let’s start with introducing yourself to your panel members. Start directly from your college experience.

[told college name, work done, competitions participated and other experience.]

       I1 transferred the command to I2 (Ranjith Kumar)

I2: What are the Operating Systems you used?

               [told about Windows and Linux in college]

I2: Any Linux operating System you used?

               [Ubuntu 14.1, Fedora 13]

I2: What are the commands you remember?

               [ told all commands I remember group wise right from starting terminal then other]

I2: How can you count number of files in a folder?

[I told I don’t actually remember the command but we can do using ‘ls command’ plus other. Or we can write script using if-else condition checking file]

(( we can do “ls | wc -l”  or using find with some parameter, or iterate every file and check if it is file or directory ))

I2: Difference between Ubuntu and Fedora?

               [told about apt-get and yum and then community response etc]

-------------------------------------------------

I3: What does ‘top’ command do?

               [ told it worked like task manager in windows, then told some details]

I3: How to see network status?

               (I actually didn’t get the question initially but then told what I know about some network commands)

I3: How to connect with different system?

               [ using ‘ssh command’ we can access another computer terminal]

I3: Since you have used ‘vi’ editor, how to go to last line in a file opened using ‘vi’ editor.

               [ I told I don’t remember, there are commands visible in ‘vi editor’ to use.]

----------------------------------------------

I4: How can we connect to different system? Explain.

               [explained about ssh command]

I4: How can we execute two commands simultaneously?

               [ using && or pipe command]

I4: How to write to a file without opening it.

               [ using >> right shift operator to echo output to file]

I4: What are the ways to find/search a file?

               [using find, locate, grep with name ]

I4: How to end a process when you see in output of ‘top’ command or when it gets hang?

               [ told about getting id from ‘ps’ command then and then using kill command]

-------------------------------------------------- 

I1: Do you know basic networking, subnetting etc?

               [ told yes and my experience of network handling in college using pfSense]

I1: What is the NAT? How does it work? How to distinguish two system with same port accessing same site?

               (( Initially started with NAT description and then using table, explaining private or public ip))

               (( things got stuck when she asked me about how NAT will distinguish between same request of different computer with same port. I told using table writing MAC address along with all details. But she confused me when request is served back from server to client and in Ip packet we will be writing MAC address of main router))

I1: What are the TCP Congestion Policies?

               [told about rwnd and cwnd, slow start exponential algo, AIMD and then detection. After detection back to slow or AIMD.]

I1: What are the difference between layer2 and layer3 ?

               [ told differences in terms of devices, mac and IP, etc.]

I1: What is the layer 2 protocols?

               (( I got confused, I was not remembering exactly what to told, she gave some hints but I was not able to say))

Result : declared on 7th July 2020. I was Selected.

Gate Score – 807, EWS

----------------------------------------------TAKEAWAYs

1. After Gate, please revise basic Linux commands and basic scripting (search in Google for important commands), commands related to networking. Linux and windows differences, problems. It is good to refresh your Linux memories even you get selected or not.

2. Revise ‘Computer Networking’ subject and watch videos for practical working of some basic protocol if you are not able to visualize. For other subject like OS depends on panel.

3. If you do not remember exactly then at least say what is in your thinking in that concept, how you are visualizing. Accept your mistake.

4. Although this year (2020) there was no programming test, but be prepared for that.

5. Still having doubt, then read their requirements, understand important topic. Visit their head page, RA page. Mail them.

I have read “A Practical Guide to Linux Commands, Editors, and Shell Programming” Book by Mark G. Sobell in college for Linux. I have googled out basic important commands to refresh my memories.

----------------------------------Information About Sysadmin (outsourced from RA)

• This year 2020 there is new program MS by Res. But it is open for TA and RAP category people only. That means RA would not be allowed. (if you are thinking to join)

• This is RA position (Institute RA) where you have to invest your time in CSE Lab under Sysadmin head.

• Officially it is 20hrs per week. Less in first year. More in second year (more work). Third year you would be busy in MTP (Major Thesis Project). However, mostly it stays below that but can get over the limit in rare cases ( Load is variable). Therefore, until you do your seminar and presentation you will be doing RA duties.

• Work is mostly systems related. Like maintaining CSE infrastructure like the Mail server, DNS server, L1/L2 networks, biometric system, LDAP, GIT and networking infrastructure. Deploying new services and ensuring security of such services.

• This is different from IISc RA or MS in other institutes. First it is exactly of three years called MTECH – RA (not in 2-3 year range). Second no thesis advisors would be assigned from beginning (in RA). Institute RAs (CSE Sysads and CC sysads) are free to choose any faculty advisors in any field. Although there is limit on faculty for number of students they can take and there are criteria of CGPA also.

• Stipend year wise is 13.4k, 14.4k, 15.4k

• You will not be spoon-feed but seniors will be present to guide you (as they said) and you will never be given more than you can handle

• Guidance, Meeting and all depends on guide.

---------------------------------------------------My views

It is still MTech but with 3 years. Just your friends will get the degree before you get.

So  

1. if you don’t have any other options (like TA)

2. you really wanted the IIT Bombay name

3. doesn’t know your research area yet or wanted to explore. (applicable only for Institute RA)

4. interested in Linux and programming

then you can prepare for it (Institute RA).

What TA have to do in first year you have to do in two year (+1 for Major MTech thesis). That means less workload or pressure, you can explore and learn in your pace. Enjoy Bombay life one more year (subject to coronavirus relaxation).

(well if you consider it as advantage then it can also be considered as disadvantage if your main goal is placement whether it is 2 years or 3 years, you have to spend one extra year. TA have 8 hrs. per week load. And they will learn to efficiently manage their time in this competitive world. And some have published the paper even in 2 years duration.)

-----------------------------------------Why I have chosen sysadmin RA?

Well, it was the closest which I can relate to my past experience. (next was CC sysadmin).

I have spent my last two and half years of BTech in computer lab of my private college. I have been developing projects for my college under HOD or Director (I wish I would have practiced competitive programming). From third year I have managed the entire networking of college using firewall pfSense (learning through documentation or videos) and then incorporating it using college management system we made (me and my friend) using radius database and captive portal.

Even I have installed windows 7 and Linux in each 100+ old poor computer system. I got to know some problems of dual booting, partition, correcting errors, sometimes exchanging RAM or Hard disk of system to get things done etc.

I even tried every Linux at that time (ubuntu 12, ubuntu 14, kali Linux, fedora 13, fedora workstation, centos, redhat developer version, linux mint). I even tried to boot MAC OS cracked version in one of the computer in Lab (well it didn’t workout but worked in virtual system)

That is why it was my first preference. Similarly, you should choose based on your work experience and interest.

Second was I wanted to be Bombay having dreams like other and at my score TA seems difficult. Moreover my EWS certificate was getting delayed as last date for application was approaching.

Thank You for Reading. Hope It helps.

Gate score:690 (GATE CSE), Marks:62.67
Date: 20 April 2023
B.tech: Major in Mechanical and Minor in CSE

There were two professors, read out my details, they had asked to make a ppt presentation before a week, regarding all projects and other things you want to share in the interview.

1. Asked to say about projects

M: Explained, not so well tough, this was the first ever interview and I had no good idea how to present. (Projects: Final yr projects and some app and HTML/CSS website I made)

[[ Well, I made my project during second wave of covid and I'm from mechanical background, I hardly managed to go to a foundry shop and do some nonsense, well this sounds like an excuse, so I did not say this ]]

They also asked about the minor in CSE that I had, which I explained.

They asked what rank you had in college, I said we had no concept of ranking in college.

Technical part

1. Define rank of a matrix

M: Wrt. column space, no of independent cols we have is the rank, and wrt. row space, same thing

2. Is rank in col. space and row space same?

M: Yes in square matrix (I said)  (It's actually same for rectangular matrices too)

3. Prove it

M: I said, if we transpose, row become col and vice versa, and since rank of A and A transpose are same, the rank should be same. They were not at all satisfied with this answer, Like the professor would have punched me for this answer, if it was allowed : )

Next I explained the answer with help of geometry, If I loose a dimension we'll be able to place a vector of a reduced dimension. So rank must be min of MxN, I explained with a 3×4 matrix with abstract values, here they said, what you're trying to say is correct, but we need a proper mathematical derivation.

Then they tried to give a hint, convert to echelon form, but I was dumb enough to not get the point.

Take a matrix, they said, I took this:

$\begin{pmatrix} a & b & c & d\\ e & f & g & h\\ i & j & k & l \end{pmatrix}$

Now he said, I want to remove the forth col “d h l”, Can I do it? 
I said “Yes” cause we have max rank 3 and, 3 basis are sufficient fo it, so we can eliminate one of the 4 columns. Well, he was not satisfied.

Now he said to reduce it, even tough it was possible to work with a abstract matrix, in that pressure, I said I want to take another matrix with numbers and now took this.

$\begin{pmatrix} 1 & 2 & 3 & 4\\ 5 & 6 & 7 & 8\\ 9 & 10 & 11 & 12 \end{pmatrix}$

As soon I was done writing the matrix, he said me say it’s rank immediately, within seconds, I said 3, he was not satisfied, said to do “R3=R3-R1” and “R2=R2-R1”, Well, now I figured out what was wrong, now he asked what’s the rank, I said “It’s one”, he said what one???
I took some seconds and said, it’s two for sure. Well out of all possible 3 answers, I said all of them, one would have been definitely right, this thing was quite embarrassing.

4. Prove, if we raise the power of a matrix, the eigen values are also raised to power.

I proved with the diagonalization formula, but then he said to prove using basic (AX= λX) I did both.


5. Is every matrix diagonalizable?

M: No, if det (A) =0 it's not, realizing after some seconds I'm terribly wrong, then I said no the matrix with eigen value, then he pointed out "is it eigen value"

No I said, it's the matrix with eigen vectors (it's always easy to confuse with eigen value and vector)

Then he asked what I want to do if I join robotics

I said, want to do the programming part, again pretty dumb (maybe it could have been better to say controller codlings like using ROBOML, etc)

So, here it ends and I left the room.

I finally figured out the actual derivation of the thing (raw rank equals col rank) I will put it in simple terms here, the hard one you'll find it in the net, anyway…

It goes like this: 

1.  Piviot Defination: All before the piviot must be zero
2. Change the Matrix to, RREF (Row reduction Echelon Form) [ See we always have a linear transformation who can do this task by multiplying it to the original matrix ‘A’ ]
3. Change the Matrix to, CREF (Col reduction Echelon Form) [ See we always have a linear transformation who can do this task by multiplying it to the original matrix ‘A’
4. When we are done this the matrix always changes to something like this [ and always use piviots to do reduction ] « This is important 

After RREF, we get something like this:

$\begin{pmatrix} a & b & c & d\\ 0 & k1 & k2 & k3\\ 0 & 0 & k4 & k5 \end{pmatrix}$ 

or like this :  $\begin{pmatrix} a & b & c & d\\ 0 & k1 & k2 & k3\\ 0 & 0 & 0 & k5 \end{pmatrix}$ 

or like this :  $\begin{pmatrix} a & b & c & d\\ 0 & k1 & k2 & k3\\ 0 & 0 & 0 & 0 \end{pmatrix}$ 

Similarly do CREF on this and we’ll end up only with piviots, like this:

This is best case full rank :  $\begin{pmatrix} a & 0 & 0 & 0\\ 0 & k1 & 0 & 0\\ 0 & 0 & k5 & 0 \end{pmatrix}$  

Or like this (here we loose a rank):  $\begin{pmatrix} a & 0 & 0 & 0\\ 0 & k1 & 0 & 0\\ 0 & 0 & 0 & 0 \end{pmatrix}$  

In tough maths we say it like this: We multiply two matrices, say X and Y with A as, A’ =  $X^{^{-1}}A Y$

Doing this we get something like: $\begin{pmatrix} I & 0\\ 0 & 0 \\ \end{pmatrix}$, The dimension of I is ‘r’ which is rank and is same wrto both row and col.

Fingers crossed, mostly will not get selected, but was a good experience, and there are bed bugs at Bangalore, better take good hotel, I hardly slept the last night and my eyes were red, the professor asked me once, did you not sleep or something, I said no I slept, I thought, maybe it's not so wise to make excuses.

Verdict: NOT SELECTED

The derivation of (Row Rank = Col Rank) 

Formal one: https://ocw.mit.edu/courses/18-701-algebra-i-fall-2010/dfd72d3d4a11988c2335b5e9a79ce48b_MIT18_701F10_rrk_crk.pdf

My notes:
one correction: echlon form is always of the form: R2 = R2 - (k * R1) , I did this a bit wrong here

IIT Patna (Mtech in CS, Research Fellowship)

1. What is the probability of getting 2 consecutive heads in a fair coin toss?
2. What is the probability of getting a prime number when 1–10 is randomly sampled?
3. What is the probability of getting a prime number given that the number chosen is greater than 5?
4. You are given 2 unbounded numbers to add (assume that these 2 numbers can exceed the max capacity size_of_int of the given machine). Write a program to store and add these 2 numbers. (Hint. Use linked list)

IIT Jodhpur (Mtech in CS, Self Sponsored)

1. Basic questions of Joint and Conditional Probability.
2. You are given an array of size n from with consecutive integers but one number is missing. E.g. {1,2,3,5,6,7}. Write an algorithm to find this missing number. What is the running time of the best algorithm for this? Can you use the formula for the sum of natural numbers till n to design this?
3. Define inverse of a matrix, mathematically and intuitively.
4. When does a matrix not have an inverse?

IITH (Mtech in CS, Self Sponsored)

1. F(n) = 100n; G(n) = n². F(n) = O(g(N)), is this true or false? In what cases is this true or false?
2. You are given an array ‘a’ of size ‘n’, where all the elements are 0 except for 1 element which is 1. You have a function Sum(a, j) which return the sum of the elements of the array from i → j. E.g Sum(a,5) will return the sum of elements from a[1] to a[5]. Using Sum(), what is the least number of calls needed to determine the index r S.T a[r] = 1. (Hint: use divide and conquer)
3. Given a polynomial P(x) = x⁵ + 4x³ + 6x + 5. Assuming you are given only one temporary variable t and the value of x, what is the minimum number of operations needed to compute P(x).
4. A word of variable size is generated with random permutations of the alphabet a-z. What is the probability that the letter ‘a’ appears before ‘b’ (assuming that they appear only once). (Ans: 50%)

If this helped you feel free to like and share!

Interviewer  :--- Hi , Introduce yourself.

Introduced name , GS-698, cat-EWS, Btech in biotech From NIT Durgapur

There was silence for 30 secs after I told biotech

Int:--

Why MTech?

Me:- want to work with computer vision in future and primarily i want a cs degree to be eligible for jobs

Int:- subjects u want us to ask from?

Me:-- LA & prob, OS, DS

Int 1:--  have u heard of linear regression? (me → yes) then tell me if y=A theta ;  then theta = A^-1  *  y ? Am i right?

Me :-- confused with few terms he used in terms of linear regression(like feature vectors and all ). I said as per linear algebra yes

He:- always? 

me:- no, if A is non singular then possible, 

he:--- if that's a non square matrix?

me:-- no still not possible

-----------------------------------------------------------------------------------------------------------

He went somewhere, interviewer 2 comes, “ it seems u are having difficulties I will go for very basic questions.”

Int 2:--  A min heap is there .. TC read to get the max element ..

Me:-- O(n)

He:- how?

Me:-- max element is present at the lowermost layer… so we can traverse the min heap using in/pre/post order and just get the maximum

---------------------------------------------------------------------------------------------------------------------

He:-  how to write a program for returning 1 if it has     A[i]= i   or else -1     , if the array nos, are DISTINCT Integers and sorted

me: – traverse it and check the condition

He:--- TC ??

Me:-- O(n)

He :--- optimize it    (Sorry sir,dont know, after thinking a few moments [i missed the word ‘sorted’ in tension])

------------------------------------------------------------------------------------------------------

He:- Prove that for a graph at least 2 vertexes will have same degree.

Me:- Told

he:- ok

----------------------------------------------------------------------------------------------------------

He:-- prove that a DAG has at least one node of indegree 0

Me:- tried but can't do

-----------------------------------------------------------------------------------------------------------

He :--  there is an array with n elements of which k are distinct. Sort them and prove that there TC for this prog is n log k

Me :---- tried but can't do , said sorry sir 

Ok lets try OS as u said,

Me :-- ok Sir

He:-- page size if made smaller what's the advantage and disadvantage

Me:-

the advantage is in an average there is a wastage of page size /2   so if lesser the page size lesser is the wastage

he:- ok and disadv?

me:- disadvantage is lesser the size for occurrence of page fault and thrashing.

he:-- all that's fine, but  i am looking for some other points

me— blank

he :-- it has some effects on page table?

me :-- yes sir the page table size will  increase

he :-- hows that a disadvantage

me:-- sir Page table is an extra burden to the MAIN MEMORY hence , increasing its size is increasing the burden.

he:--- ok, i am done , ask if u have any questions

me:-- no questions, thanks for making me eligible to for the interview

he:-- don't worry, being from biotech, u were good...thanks

me:-- thank u

So this was the scene, it didn't go up to the mark, lets see.

Whatever be the result i am pleased with their patience and gesture of the profs , they were very good and tried to pacify me as much they could

This year IISc had record number of applicants for CDS Department. So they had divided the screening process into 4 days, each day having 2 shifts.

The screening process had a written test(Different tests, based on if you choose CD-CS or CD-CP), succeeding in which, was followed by an interview. The written test had 5 simple questions to be solved in 30 minutes. Questions were almost as easy as the GATE 2019 paper.

They called me on 20th May, morning shift, 9am, so naturally I reported at around 8am. The exam started at 9.10am’ish time, went upto 9.40am. Soon after the exam got over, I asked Yogesh sir, if we could quickly check the canteen, as I was hungry as hell. I was told that results will be declared at 10am sharp, and I should decide if I would be on time. Prakruti, the canteen, had a huge queue at the token counter, so alas, I stayed hungry.

Shortlist was out. My name was called, was asked to report at room 201. Waited for quite sometime outside, listening to “Hall of Fame”, by the Script, on loop, on my headphone. and then came my turn. I was called in, and asked to take a seat.

(I DONT REMEMBER WHICH QUESTIONS WERE ASKED BY WHOM, SO I WOULD USE “I” IN GENERAL FOR INTERVIEWER)

I: So Mriganka Shekhar Chakravarty is your name. And you have a Gate score of 729, with an AIR of 558. Am I correct?

Me: Yes, sir.

I: I see you have chosen CD-CS with Cloud Computing as your first choice for lab. Is it correct?

Me:Yes Sir.

I: But, Mriganka, in the online form where you were supposed to make choices, you selected CD-CP as your preference and now you have switched to CD-CS? Why so?

Me: I dont remember sir, however, that indeed might be a mistake on my part.

I: Okay. No issues. So tell me Mriganka, what are your strengthened subjects?

Me: I feel comfortable with Algorithms and Data Structure.

I: But you have chosen Cloud Computing as your lab right?

Me: Yes sir. But I believe, Algorithms is a subject, which if strengthened can be a launchpad for any other stream of specialization.

I(Everyone smiles): True that, but knowing algorithms is a “Necessary condition, not a sufficient condition”.

Me: I agree sir.

I: Okay, Mriganka please stand in-front of the board, and draw a grid structure.

(TRUST ME, THE WHITE BOARD WAS HEAVEN….. IF YOU EVER INTERVIEW AT ROOM 201, YOU WILL KNOW IT)

I: So Mriganka, you are standing at (x,y) on the grid, and you wish to go to (p,q). What is your shortest path?

Me: Sir, if you could kindly stress on the constraints. Am I allowed to take diagonals on the grid?

I: Yes, you can take right, down and diagonals.

Me: Explained my approach. I started scribbling the mathematical model of the situation.All the while, I kept speaking of what I am thinking. After, sometimes, I came up with the equation that gives the shortest path, dependent on x,y,p,q.

I: Can you prove it?

Me: I started the proof. Stumbled. kept scribbling. I failed. I however remember saying, “For this to be shortest, we need to show, that (x,y) to (p,q) cant be reached any any number of steps shorter than this, basically we need a contradiction approach”.

I: Okay fine. No problem.

I: So do you know what a diameter of a graph is? It is the longest of the shortest paths within the graph. So given a graph, can you work out the length of diameter of a graph?

Me(Holy F**k inside…premature optimization is root of all problems, take it easy and brute force :P): Sure sir. So it is a shortest path problem. Let us run Dijkistra’s on all the vertices, and from among them choose the maximum. This is easy.

I: Okay…. So what is the complexity?

Me: It is O(VElogV) for dijkistra run V times. and O(N^2) for choosing the maximum of the shortest paths. So the complexity is O(EVlogV)+O(V^2).

I:Can you optimize it further?

Me(Quiet for a few moment): I can only worsen it with Floyyd Warshal, with a smile!

(He was probably looking for Johnson’s Algorithm)

I: Okay, Mriganka draw a binary tree.

Me: Drew.

I: Count the number of children, and the number of nodes with two children. and name them N0 and N2.

Me: Did.

I: Now you can see, that N0=1+N2. Prove it.

Me(I WONT USE INDUCTION): Started working around with the degree equations. Got tired after sometimes(I AM HUNGRY). Sorry sir, it would be helpful you could give me a direction to work around(with a smile).

I: Use Induction.

Me( :( ) : Did that.

I: Okay Mriganka, take a seat.

(I DID NOT NOTICE, BY THIS TIME THEY HAD BISCUITS AND SNACKS ON THE TABLE, AND I WAS HUNGGGGRY)

I(No they did not ask me to take snacks xD): Asked a few questions from operating systems, on process isolation and stuffs.

Me: Answered, but I am not personally satisfied with the OS interview. I could do better.

I: Okay, Mriganka, you may leave now :)

Me: Thank you sir :)

I: You must be really hungry. Have some food. You were the one asking to check the canteen out right?

Me: Yes sir, I am reaaaly hungry. Had nothing since morning.

I: See you.

24th May…………….CONGRATULATORY MAIL :)

“Structured, conceptual and practical test of subjects.”

Hi,

I am one of the eight fortunate ones who were selected for OCES Computer Science program last year. I am Abhilash Bhardwaj, currently working as Trainee Scientific Officer in BARC, Mumbai. Last year I was shortlisted for interview based on my performance in BARC TS Online Exam ( 170/300 while cut-off was 159) . Approximately 100 students were called last year for interview, out of that, 8 students were finally selected for this program ( 765/1000 Interview Score where Interview cut-off was 650).

So now coming to interview experience.

My interview was scheduled on 11th June last year. I reported in the morning. After basic document formalities I went to the waiting room. I was second in sequence so nearly after one hour my name was called by the panel. We all have fear of interview especially when you know this is going to last for an hour or so. I entered into the interview room. A total 6 people were there in the room. They started with the basic introduction about my college, my cgpa ( they asked how you managed in college ), my native place etc, just to make me comfortable with the panel.

And here it begins !!!!!

The first question was by the President regarding the subjects that interests me more.They did not ask me to list it down but I jotted it down on a paper. I wrote Operating System, RDBMS, COA , DS and C. Just when I finished,the panel asked that why you have written COA, as most of people don’t write this. ( Don’t answer like its my favourite subject and all, you need to justify it ). I answered the relevance of advancement of architecture, processor design, multiprocessor systems, GPUs in current era. I gave examples of Blockchain and Machine learning where we require high computing power. Then, as I mentioned, I used the term GPU so they began with that… ( so the moral of the story-don’t use just fancy terms if don’t know it!!). Fortunately I was aware of basics of GPU. They asked whether is SIMD,MISD,MIMD or SISD, why we are using this,how it makes computation faster,can’t we achieve the same with CPU, power requirements of CPU and GPU etc. I was knowing the plot not the entire story so at last I surrendered on a comparative question of CPU and GPU, I accepted my defeat. They responded don’t worry it was out of context because of your interest in GPU we asked this much. Then they asked basics of RISC, CISC,current RISC architectures, difference of RISC and CISC, Microprogramming and its types ,Pipelining hazards, how we avoid them, Linking and Loading operations,Addressing modes, CPU flag register etc.

Here my suggestion is to speak relevant to the topic but take examples, explain on paper sheets, draw diagrams. Like when you are explaining Microprogramming start with why we need this, then its categorization, difference etc. They will ask question in every step of explanation. You need to know why RISC, What is RISC and How it is implemented. These concepts are not beyond our understanding. If you don’t know the answer better to say sorry!

Then they switched to Operating system. They started with what was taught in B.Tech. Then they asked me write a critical section program where I was needed to produce H2OH2O. But with different constraints. I used mutexes, again they they asked why mutexes not semaphores ? what advantage you will get by using mutexes? After producing H2OH2O in three different constrained way they asked me a basic question, lets say CPU generated a virtual address, now you tell us complete steps to get the data (structured, conceptual, practical question ) . It looks simple but while answering the question they asked about TLB and its use, memory heirarchy, then different types of cache memories, physically addressed and virutally addressed cache, how page translation is done, what happens if page fault occurs, why interrupt is used when page fault occurs, concept of virtual memory and its use etc. I explained all steps with diagram by taking examples. Then they asked about thrashing, Page replacement and Belady’s anomaly, example where FIFO algorithms shows Belady’s anomaly.

Then they asked a bit more about virtual memory.

After OS they shifted to RDBMS, they started with why we require normalization and what all concepts you learnt in B.Tech. Then they asked me to write a nested SQL query to fetch some data ( I remember it was lengthy ). Then they asked about locking mechanism in database, how locks are implemented in any database, what data structures are to be used to implement locks and some questions related to transactions.

Next they started with C. Process image in RAM when program is loaded ,basics of all four segments and what they contain ,what is an extern variable and its use,storage class of global variables,how to define structures in C ,represent a rectangle using structures in 2D coordinate system then using this structure to write a program in C to check whether two rectangles are overlapping or not .I defined rectangle initially four points but they asked to improve it, further I changed it to origin points, length and breadth. Then I wrote the function to check the overlapping.

Overall, interview was pretty nice.I answered most of the questions. There were very few places where I was stuck and wherever I was unaware of the exact answer I said sorry. Like they asked me about convex hull and I was not much sure about that so straight forward I said sorry.

My basic strategy was to stay calm, listen to the question carefully and to think before answering even if the question may seem very easy. I used the given paper sheets to draw diagrams, write examples. Whenever it was needed I explained the things by showing steps and sequence on paper. I related my learnt concepts with real life as well as other subjects, like COA with OS, Transactions with shared memory access etc. Throughout the Interview the panel will help you .When you get stuck they will try to point in correct direction so that you can rectify yourself.

Thank you for your utmost patience to give it a read.I hope this small piece of my experience will be of some help to the aspirants. All the best !!

I will be posting some other contents related to BARC. Feel free to reach me in case any doubts:

https://www.linkedin.com/in/abhilash-bhardwaj-6000b7b4/

www.facebook.com/abhilashbhardwaj.kasap

IIIT, Hyderabad GATE Overflow Interview Experience Links: 2018 to 2019

IIIT, Hyderabad Other Interview Experience Links: 2012 to 2019

Date – 06-July-2020, Duration 43-45 minutes (2:45pm to 3:30) (online using Google meet platform)

There was one seminar before the actual interview to familiarize the candidates with the process and area. We have to write our preferences in Google doc shared 5-6 days before.

Background Subject – Computer Organization, Operating System.

Research Sub-areas – Database, Operating System

Started with presenting my application profile, then asking basic question related to year gap, and Gate Score.

Asked about preference between Database and Operating System. (I said I like both)

Prof. Deepak D Souza was coordinating between faculty - Prof. Vinod Ganapathy (asked question for OS), Prof. R.C. Hansdah (Database), Prof. Matthew Jacob (computer architecture).

(I will try to frame questions as exactly as they said, and will give gist of answers I told, as thinking and presentation skills are different for different persons)

---------------------------------------------Started with Matthew Jacob Sir.

1. Can we represent any real number in computer?

[Told about floating point IEEE 754, or rounding techniques involved, range involved and if some are number are not able to represent then we have to round them.] [ that is not any but within range]

2. What is the format for IEEE single precision format with subparts?

[Told with proper explanation and showed the picture also.]

3. How do we do floating point addition in computer.

[Told about normalizing result and adjusting exponent.]

4. Can we pipeline the floating-point addition?

[Yes, initially i didn’t understand then he asked about pipelining]

He got disconnected midway and couldn’t join. (may be network problem)

-----------------------------------------------And Vinod Sir took the command.

He showed slide pictures and asked basic question on it.

1. Showed the slides, Picture was like

      int p = 1234;           // (some number)
      printf(“%d”, &p);

1. How printf works.
2. What is the role of OS?
3. What is system call. What does it do? we have library file where printf code will be there, so how does system call work

[ I started with explaining system call behind the printf() function, then he asked question mentioned above ] 

((he asked if have printf working code in library file then why we need system call, since printf code will do the work))

2. Showed next slide

     printf(……)
     {
      // implementation of printf
     }

1. How system call is different from normal function call. (again told about OS, security and system call)
2. What exactly it will differ in hypothetical OS.

 (told about user mode, at that point I understand what I have to say in previous question, he immediately asked me about how user mode will be converted to kernel mode. I said there is bit. He said who change it. I said OS. He said How. I was not knowing at that time)

3. Showed one more 

running the both code in uni-processor system.

//code 1
[p1]  int *p;
[p2]  p = 12345566h ;    // some address
[p3]  *p = 1;
[p4]  printf(“%d”, &p);

//code 2 
[q1]  int *q; 
[q2]  q = 12345566h;    // same address
[q3]  *q = 2;

1. What will be the output when it runs parallel in the uniprocessor system? (told about race around condition)
2. Which line would require the OS help? (confused about p3, told about p1, p2, p4)

---------------------Jayant Sir was not present so, database question was asked by RC Hansdah sir.

1. What is the definition of relation in Relational DBMS? (told)
2. What is mathematical definition of Relation? ( I got confused I said I don’t know, I haven’t read. But after interview I think I could have said relation definition I studied in Discrete Mathematics)
3. What is candidate key, Foreign key, Primary Key?  (told)
4. Difference between Primary Key and Foreign Key? (told)
5. What is transaction?  (told)
6. What are the properties of transaction? (told about ACID property)
7. What is 2pl locking protocol? (told about its two phase and working)
8. How does It maintain the serializability? (told how 2pl block transaction requesting for conflict resource)
9. What is 2PL commit protocol? (I haven’t read about it, so told doesn’t know. this protocol is related to distributed system)

In the last they asked about if I am having question and It ended.

Result: declared shortlist on 14-July-2020. Not selected.

Score: 807, EWS

Takeaway:

• I think I should have clear priority of subject I have chosen. It gives them idea on my research interest.
• Apart from OS, I have been asked basic question. But for OS, I think if I have taken a deep breath and then answered the question, it would have helped me to present my answers beautifully. 
• System Call, BIOS working, some topics required reading books apart from Gate preparation.

I have read “Principles of Operating Systems” book by Naresh Chauhan. I liked the book as it has all the basic content.

Hello Everyone. I am Neelam Singh passed out in Aug 2021   from a private Engineering college in M.P Bhopal. I appeared for BARC written test in CSE on 25 Sept 2021 and interview on 11 Nov 2021 and by god grace ,I cleared the interview in  first attempt. 

How I prepared? 

I took guidance from Deepak Sir and Sachin Sir from GO classes. GO Classes helps me to clear my concepts and build my career . All the teachers explain in very detailed and nice manner and also have doubts classes at the end of every class. Sachin Sir and Deepak Sir are highly supporting ,knowledgeable and friendly. I will suggest every GATE and PSU aspirants to go through the free course of DM and C on GO Classes.You will love it . 

For written test , I went through the notes of GO Classes and Applied Gate .For interview I refered GO classes notes(for C, DS,Algo) , Geeksforgeeks articles(for C,DS, Algo, DBMS) and GateBook notes for CN .

What all subjects I chose for Interview?

I chose C, DS, Algo , DBMS ,CN . But they also asked OS . They consider one programming language and OS as almost  neccessary  .

what all questions they asked ?

C

1.Write C program to merge two sorted arrays into one and return new sorted array. 

2.Why you prefer C over other languages ?

3.Where global and static variables are stored ?

4.How will you return an array build inside a function? (Hint:- using malloc )

DS

1.State some uses of stack DS?

2.How System Stack works?

3.What all activation record contains?

4.What DS will you use to store variable length URL?

5.Write node structure for stack used for storing forward and backward links/URLs visited , while browsing?

6.How stack helps in storing /performing undo or redo operations on the URL visited?( Hint:- By maintaining 2 stacks )

7.Write code for push and pop in stack implemented using Linked List?

OS

1.What is OS?

2.What are all functionalities of OS?

3.What is process?

4.Draw process state diagram?

5.What happens when process is in new and end state in process state diagram?

6.What all resources are allocated to a process?

7.What PCB contains?

8.How PCB is implemented?

9.What is process synchronization?

10.How process synchronization is achieved ?

11.What is semaphore?

12.Write code for synchronization using semaphore?

13.How can 2 processes access same semaphore variable?

14.If suppose a process generate address corresponding to other process memory space , will it be allowed to access? If yes , How? if no, How?

15.What kind of addresses a process generate ?(Virtual or physical)

16.How much memory , a process think it have and it actual have and how mapping is done between two? (concept of virtual memory and pagetable ).

17.What is swap space?

CN

1.Explain how a process will send data to another process on host on another network ?x

2.How ARP protocol works?

DBMS

1.What is transaction?

2.State properties of transaction?

3.How isolation is achieved in transaction management?

4.What if we allow non-serial schedules?

5.What is normalization and explain its type?

6.Do normalization impact performance . If yes , How?

7.When should normalization be performed and when not?

ALGO

1.Suppose you are given a array, return N subarrays such that their sum (sum of elements of each subarray) difference is minimum . Suppose S1, S2,..Sn are n subarrays sum ,then |S1-S2| +|S1-S3|+….+|S1-Sn|+|S2-S3|+|S2-S4|+…. should be minimum . Give algorithm for it.

2.Give greedy algorithm for above problem?

TIPS:

1.Prepare one programming language and OS .

2.Explain in detailed manner, every question.

3.While preparing look at implementation side of every concept , espically in OS,DS.

4.Don’t mug up the concepts . Try GOClasses once.

Hi all, I have had a very nominal performance in GATE 2021, current GATE score is ~740. I can’t afford a year-drop, so I started researching contingencies to MTech degrees at top IITs and IISc. Coincidentally I stumbled up these MS/MTech (Research) degrees. These are much more research-centric programmes offered by most IITs/IISc. I have made the following findings as of yet – 

IISc – MTech by Research in CSA. Details – https://www.csa.iisc.ac.in/academics/academics-prospectivestudents-regular.php

IIT Madras – MS. Details – http://www.cse.iitm.ac.in/docs/ms-criteria.pdf

IIT Hyderabad – 3 years MTech. Details – https://iith.ac.in/academics/post-graduate/

I am opening this thread of discussion for like-minded people to put in your inputs, so that we can all benefit from each other. I will also be putting in my inputs as and when I stumble upon new insights.

P.S – IIT M and IIT H seem to allow BTech graduates from all streams, but IISc allows students from Computer Science/Engineering, Electronics/Electrical Communication, Information Science/Technology background only. This is a sad news for me, as I am a Mechanical Engineering graduate.

hey guys,i have just written a post(or tried to write :D) on my IITM experience

REad it here

https://uddiptab.wordpress.com/blog/

Hi Everyone! 

This is Anmol Garg, I got a GATE CSE score of 749 (AIR 343) in 2022 and 742 (AIR 447) in 2021. I applied to IIT Bombay MS By Research program in CSE with my 2022 score, as I am a General candidate and knew I won’t be getting a direct offer from any top IIT.

The admission process is available here:
https://docs.google.com/document/d/e/2PACX-1vShA2OZKqslk08AYc7C5_Y-4rTMtQET5MddL0YtHnUA86wT2a2-3BBT0G2RM3LOXXUph778c-oHJMAO/pub

The process consisted of 2 rounds, 1^st round being a written test on Codetantra (pen-and-paper based) and 2^nd round being an Interview. I had chosen Computing Systems (CS) Stream for my test and interview.

ROUND 1 – WRITTEN TEST
---------------------------------------

As I had chosen CS stream, I had the option of attempting any 12 questions out of the following 3 panels:
1. Software Engineering, Compilers, Programming Languages
2. Systems Software
3. Hardware and Security

I mostly solved questions from Programming, DS & Algo, Computer Networks and Operating Systems.

Result :: SELECTED

ROUND 2 – INTERVIEW
---------------------------------

Before interview we were asked for our preferred stream (CS/TS/IS), and any RAP project (optional). I had chosen CS as my stream and Virtual Labs (https://docs.google.com/document/d/1op-KwA6B99WHKCoZOkMR3ULcIDPvvbboRWmBtT7QBNI/edit) project under Prof. Kameswari Chebrolu as RAP Project.

My interview panel consisted of Prof. Kameswari Chebrolu and Prof. Bhaskaran Raman

Initial questions were about my past projects and work experience, and the flagship projects I did when I was working.

I was then offered a choice between Computer Networks and Operating Systems as topic for Interview. I decided on Operating Systems as it is my strong suit.

OS questions were mostly from basics of Virtual Memory. I don't remember the exact questions, but some of them were like:

1. What is virtual memory?
2. In which cases is it used?
3. If you have an unlimited amount of storage, will virtual memory still be used?

After answering these questions, I was given a choice between TA & RAP. I chose RAP as the Virtual Labs project seemed very interesting.

As I have experience in Back-end and microservices development and deployment, I was mostly asked questions from that space. Some of the interesting questions were:

1. What is docker, and how does it work on a hardware level?
2. Suppose you are maintaining a set of microservices, and you notice they are getting slow. What steps will you take to mitigate it?
3. Do you know what AWS is? 
4. What can be a real-world example of implementation of feedback queue. Give examples from projects you have done previously

After answering these questions, I was told that they were done, and I was free to ask them any questions. I asked questions about the project, such as:

1. What’s the current state of the project
2. If I join, at what state do I have to start work from (from scratch or not)
3. What technologies were being used
4. What’s the current timeline for this project

I learned that the project’s back-end is being built using Django, in which I have around 1.5 years of experience, so I told them about my experience and all the projects I have done in it. It was clear that they were impressed by it.

Then they asked me that if I were to be offered admission, will I join IITB or do I have any other preference, and if I do join IITB, will I prefer TA or RAP.

I again answered that IITB is my top choice and I would prefer RAP as I wanted to work on such a large scale problem.

Then the interview ended. It lasted for around 45 minutes.

Result :: SELECTED FOR RAP IN 1^st ROUND

Hi fellow aspirants,
I want to share my Interview Experiences of Top IITs and IISc. These might be useful to some of you who will apply for MS admissions. 

Interview links: https://github.com/surajiitd/Blogs/tree/master

All the Best!!
Suraj Patni
MS by Research(CSE)
IIT Delhi(2021 entry)