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I still can’t believe that I am writing a success story after reading GATE success stories of others.

Hi everyone! I am Amit Kumar. I appeared for ISRO interview on 2nd August 2018 and secured AIR-17 in the selection panel. It was like a dream come true when I logged into ISRO careers page on the day result was out.

People asked me to share my interview experience, so I was keen to write it on gateoverflow as I have gained ample of knowledge from here.

Just a little background:

I belong to Patna, Bihar. I did my B.Tech in CSE from DIT School of Engineering (now Amity), a private college in Greater Noida affiliated to DR APJ Abdul Kalam Technical University. I am 2016 batch pass out.

My only dream was (in fact is) to get a single digit rank in GATE. But in spite of my all hard wok I have only the following statistics:

GATE 2016 : AIR-1269

GATE 2017 : AIR-546

GATE 2018 : AIR-1457

I was devastated after seeing my rank in 2018 at GO site before the result was actually announced. I didn’t even bothered to check my GATE result after that. I prepared for GATE 2018 along with job at Wipro.

Now my only hope was BARC and ISRO.

I prepared for BARC and cleared its written but was not selected in the interview in spite of an interview of around 1 hours 15 minutes. Another failure for me.

Coming to ISRO now:

Written Exam:

I got 124 out of 234 marks in the written. Just got shortlisted for the interview :P . Before that I made a blunder in filling up the OMR sheet. I did not filled and bubbled the center code at all. But I had a lucky escape.

Interview Experience:

Date: 2nd August 2018.

Venue: DOS staff Housing, Antariksh Vihar, Dwarka, New Delhi.

Time: 8.00 AM.

I reached at the venue at 7.30 AM. At 8.00 AM, document verification started. I was assigned a serial no. 4 luckily. I was asked to go upstairs and wait there for my turn outside the committee room. I was restless there, only thinking that it would be my last chance for this year. Suddenly, the doorbell rang and my name was announced.

My interview started at 10.10 AM. As I entered the room there was a U-shaped big table with around 10-12 (didn’t dared to count :P) scientists (P1, P2…P10) seated, with the panel head (PH) at the center.

I greeted them with a smile at my face and little fear in my heart.

PH: (smiling) Amit Kumar right….

Me: Yes sir

PH: Have a seat.

Me: Thank you sir.

PH: (looking at my bio data) so Amit u are 2016 pass out.

Me: Yes sir.

PH: What were u doing since then?

Me: Sir, I am working as a project engineer in Wipro Technologies.

PH: What is your job there?

Me: I am working as a JAVA developer there.

PH: What project have u done in your B.Tech ?

Me: Apparel recommendation Engine sir.

PH: Can u tell your favorite subjects?

Me: (I was expecting this question after reading interview experiences and was well prepared with GATE subjects) Computer Networks, DBMS, OS, DS, C Programming.

PH: Ok Amit. thats fine. You tell one subject from advanced computer science that u have studied in 4th year of B.Tech.

Me: (Shocked….  I had read many interview experiences. But none of them talked about this. I was cursing my luck. I thought that its all over for me…… but I thought for 20-30 seconds and then replied) Data Mining and Warehousing Sir (So that i will be able to relate it with DBMS).

PH: that’s good.

Then he asked one of the panel members to continue.

P1: So Amit, u mentioned computer networking. Bandwidth is 1 Mbps. What is the value of M here?

Me: Sir its 2^20.

P1: u know IPv6 ?


P1: If I use 1 million IPv6 addresses per second then how long would it take to exhaust all the addresses?


P1: Can you tell some error controlling techniques used in computer networking?


P1: Can u write the CRC-32 polynomial ?

Me: Sir i dont remember the exact polynomial.

P1: What are the requirements of a network?


P1: What are the factors that limits network capability?


There were some other questions which I don’t remember exactly.

Panel head then asked the other panel member to continue

P2: So Amit u mentioned Data Mining and warehousing. What is a data warehouse?


P2: How is it different from normal database?


P2: What is OLAP and OLTP?


P2: How these 2 differ and where are they used?


P2: What is Big Data? How is it different from normal data?


P2: What are the steps involved in Data mining?


P2: What is a data cube? How is it constructed?


P2: Give an example of data cube and how its used in data mining?


P2: Consider a layered architecture of a database. Lets say 3 tier architecture of DBMS. Where the validation testing will be done?


P2: Who will do it at all the 3 layers?


P2: What is Business logic?


He went too deep in the 3 layer architecture, validation testing and the roles of various stakeholders in the validation testing at all the 3 layers. He also gave some scenarios and asked my approach.

I am skipping that to keep the length of the post in check.


Then came Programming language

PH: So Amit. Which programming language are u comfortable with?

Me: C programming sir.

PH: But U work as a java developer in Wipro. Why not JAVA?

Me: Sir I have implemented most of the data structures and algorithms in C programming that’s why.

Then panel head asked other panel member to continue.

P3: Can u write a program to compute the area of any given polygon?

Me: yes sir.

He asked me to go to white board and draw a polygon and tell the approach to find its area.

I drew this:


Image result for triangle

P3: How do you find its area?

Me: half * base * height.

P3: Draw a polygon with more sides.

I drew this :                                                                                                                                                                                                                                                                                                                                                                                                                     

Image result for rectangle

P3: (Smiling) How will u find its area?

Me: Length* Breadth.

P3: Draw a random and complex polygon.

I drew this:


Image result for rectangle triangle shape

P3: How will u find its area?

Me: (Smiling) Area of rectangle + Area of Triangle.

All of them started laughing.

Then one of the panel member got up and said humorously: arrey yaar kya kar rahe ho (What are u doing). He took marker from me and said: Aankh band kro or koi sa bhi polygon bana do (Close your eyes and draw the polygon).

He drew something like this:

Image result for irregular polygon

Then they asked my approach of finding its approximate area. They gave a hint: keep it simple.

I started thinking about it. Then they asked to think loud. I told them various approaches using numerical techniques. And thank god they look satisfied and said : GOOD.

Then came Data Structures:

P4: What are linear and nonlinear data structures?

Answered (the most expected question of any DS interview).

P4: Do you know Dictionary DS?

Answered and explained about it.

P4: How can we implement it?

Me: Using hash table.

P4: How can we detect a cycle in a graph?

Me: DFS and BFS

P4: How to detect it using DFS in C?




Next came Operating System

P5: What is fragmentation?


P5: What is internal and external fragmentation?


P5: How can we resolve the problem of fragmentation?


P5: What is compaction? How will we do it?


Then the Panel head asked me to leave.

My interview lasted for around 20 minutes. It was like a rapid fire round.

Result: Success.

Prepartion Tips:


  • I followed NPTEL and youtube lectures.

  • However reading standard books are equally important and along with solving their exercises.

  • Above wont work alone if we don't practice from GO PDF (The Brhamashtra).


I Would like to wish all the best to ISRO and GATE aspirants. However I am still a GATE aspirant and working for a single digit rank.

I would like to thank GATEOVERFLOW specially Arjun Suresh sir, Bikram Ballav sir and all others who are selflessly working to guide computer science students to their dreams.

Thank you 


posted Sep 5, 2018 in Interview Experience
edited Sep 5, 2018 by


Congratulations Amit.. Wish you achieve all your dreams :)  :)
Congratulations for ISRO. :)
Hi Amit,first of all congratulations on your succes.I am the one who was talking with you in document verification hall and outside interview room.Since declaration of result I was finding you on facebook to congratulate you.All the Best!!!
Thank you everyone :)
@Sagar Yes i do remember sagar. Thanks for your wishes. I wish u all the best :)
congratulation bro...starting question was really amazed, thanks for sharing your experience
Hi Amit... Congratulation... how much percentage you have in your B.Tech??
@swaraj its 75
@Amit Bro how much you got in the interview???
@Swaraj i got 74.22 %

@Amit- Many Congratulations to you :)

Scoring such GATE ranks, BSNL, BARC and then ISRO is amazing. Moreover, you did this all while serving WIPRO with all dedication. You are an inspiration for many. You truly have Better Intelligence :)

@Mamta- Thanks.. I am highly obliged to receive a congrats from AIR 1 :)

And thanks for highlighting the important words specially all dedication, so that i get the sarcasm straight away. Now coming to the word Better intelligence, it took almost 2 years to achieve AIR-17 in my case...intelligent are the people who just take 3 months to top the list so that they need not press ctrl+F and get interviewed as a Topper:)