Sample BARC Interview

The attendant opened the door for me, there were five members including the Chairman sitting around a circular desk. My seat was opposite to the Chairman's and I had two Members on either side. It was more of a discussion desk rather than an interview desk. Let us call the members as CM, M1, M2, M3 and M4.

Candidate : May I come in Sir?

CM : Come in, come in.

Candidate : Good morning Mr.Chairman, good morning sirs.

CM : Good morning, please take your seat.

Candidate : Thank you sir.

CM Asked few questions on schooling and my Btech to make me feel comfortable.

Candidate : Answered.

CM Write down your 5 favourite subjects on the paper.

Candidate : I wrote Computer Networks,Operating System , Automata ,C and Data Structures,Algorithms.

CM : Shall we begin?

Candidate : Yes sir.

CM : Tell me how to dynamically declare a 2D matrix ?

Candidate : I wrote:
int **arr = (int **)malloc(r * sizeof(int *));
for (i=0; i < r; i++)
arr[i] = (int *)malloc(c * sizeof(int));

CM : Why are there 2 stars (*) for rows and only one for column.?

Candidate : We can create an array of pointers dynamically using a double pointer. Once we have an array pointers allocated dynamically, we can dynamically allocate memory and for every row.(I took a long long time for this one because they cross questioned at every point)

CM : Hmmmm.. where are they allocated in memory and draw a stucture of memory allocating the memory.

Candidate- I draw some boxes with pointers and 2 of them started laughing to make me nervous.

M1 : How do memory segmentation fault happens.?

Candidate : A segmentation fault occurs when a process attempts to access memory in a way that the operating system and processor cannot or will not allow.

M1 : Reasons for segmentation fault?

Candidate : The most common cause is reading from or writing to memory that the process is not authorized to so access. For example, processes do not have access to the page of memory beginning at 0x0 and thus dereferencing the NULL pointer results in a segmentation fault.

M2 : If you are an OS developer how will you ensure that segmentation fault does'nt occur?

Candidate : I suggested some approaches but they were not convinced and some were smiling on my answer that made me nervous.So I asked for water.

M3 : Should we switch to CN?

Candidate : Yes Sir!!

M4 : Tell us how a connection starts from a device to another device.

Candidate : I explained the whole TCP/IP model and they were convinced.

CM : How will you ensure in the connected devices one device will not write in other device's memory,or will not harm other process running on that system.

Candidate : Explained about Ports and their roles in the connection.

CM : Lets switch to algorithms

Candidate : Ok Sir.

CM : Tell me about quick sort complexity.

Candidate : Explained the whole concept and how it works.In which case it is n(logn) and in which case it is n2

CM : How can you ensure that you are not constructing flat BST.. ie All elements are in a line like a linked list

Candidate : We can use Balanced binary trees and balance the nodes at each step.

M3 : M3 gave me some numbers and told me to construct a balanced BST showing each balancing step.Show left rotations and right rotations.

Candidate : Got stuck.. :(

M3 : Difference between AVL and Red Black tree.

Candidate : I had some idea so told them what ever I knew.

M4 : How do you convert a balanced BST into a linked list.

Candidate : Suggested some recursive program.

M1 : To lighten the interview they asked me why do you want to come to BARC.

Candidate : I like the research and productive environment plus it is govt associated so gives me pleasure.

M1 : Ok nice.

CM : Write the DP of Knapsack.

Candidate :
0 if i = 0 or w = 0
c[i,w] = c[i-1, w] if wi ≤ 0
max [vi + c[i-1, w-wi], c[i-1, w]} if i>0 and w ≥ wi

M1 : Differnce between Fractional and 0-1 Knapsack??

Candidate : In fractional Knapsack you can take portion of the whole to maximise the cost while in 0-1 knapsack we either take the complete product or dont take it at all.

M1 : Design a DFA for accepting even number of zeros and odd number of ones.

Candidate : I got stuck but finally drew it.

CM : Ok You may go.

Candidate : Thank you sir,

The result was in my favour.Interviewers were cool and will ask you tough questions and will make you nervous but in the very next moment all of them will become friendly and calm you down. My Advice would be to brush up your basics and don't try to be over smart in the interview.Be confident and answer specifically otherwise they will frame new questions from your answer.

Must read books for the preparation


Interview Questions

  • Program to check number is prime or not.
  • Given a string,in which anything except digits are treated as separators, and between each set of separators,there is some substring. count number of separators and substrings and return it with only 1 return statement.(They will provide u hint throughout ur attempts.)
  • Program to validate date given in any format like dd/mm/yyyy or dd-mm-yy etc .
  • DFS
  • BFS
  • String Reversal(w/o lib function)
  • String Concatination
  • Which compiler did you use for c programming and which version?
  • Which shortcut is used for compiling and running the program on this?
  • Can you explain the process of compilation?? (May ask many things concerned with compilation process like preprocessing, linker , libraries , assembler. In other words you can say the real fight starts.)
  • Fibonacci
  • Factorial(Explaiin EVERYTHING in the programs asked)
  • Explain recursion?
  • Write the syntax for the declaration of array and structure. What is actually passed when we pass array and structure in a function?
  • Everything about POINTERS and DOUBLE POINTERS

  • DS:
  • Why do you use DS.
  • Some non linear data structures.
  • Uses of tree DS.
  • Why to prefer Linked list over array when array has constant access time and I have no problems with efficiency of running time( deletion,insertion) in array and when array can be allocated dynamically too.
  • Program to compute height of tree.
  • Is tree used in any of routing algos?
  • What actions are performed when a function is called and returned ?
  • What is a linked list ?
  • What are the advantages of linked list over array(static data structure) ?
  • Can we apply binary search algorithm to a sorted linked list,why ?
  • What do you mean by free pool ?
  • What do you mean by garbage collection ?
  • What do you mean by overflow and underflow ?
  • What are the disadvantages array implementation of linked list ?
  • What is a queue ?
  • What is a priority queue ?
  • What are the disadvantages of sequential storage?
  • What are the disadvantages of representing a stack or queue by a linked list ?
  • What is dangling pointer and how to avoid it ?
  • What are the disadvantages of linear list ?
  • Define circular list ?
  • What are the disadvantages of circular list ?
  • Define double linked list?
  • Is it necessary to sort a file before searching a particular item ?
  • What are the issues that hampers the efficiency in sorting a file ?
  • Calculate the efficiency of sequential search ?
  • Is any implicit arguments are passed to a function when it is called ?
  • Parenthesis is never required in Postfix or Prefix expressions, Why?
  • List out the areas in which data structures are applied extensively?
  • What are the major data structures used in the following areas : network data model & Hierarchical data model.
  • If you are using C language to implement the heterogeneous linked list, what pointer type will you use?

  • OS:
  • Which OS do you use and what is difference between MAC and Windows.
  • Can we install MAC on intel machine and windows on mac machine. yes or no. if no why.
  • What is semaphore?
  • What are the conditions of deadlock?
  • Can you explain Banker’s Algorithm?
  • What is thrashing? How to get rid of it?(Working-set model concept)
  • Paging.
  • Segmentation
  • Complete file system FAT Tables inodes etc
  • Difference between paging and segmentation
  • Internal and external fragmentation.
  • Good choice of page size and page size in windows.
  • If virtual address is not in range of valid address what happens.
  • After trap,what is state of process and they asked will, after trap, process become ready??
  • Only size is sufficient for checking valid address range of process???
  • What is there in page table entry.
  • In which conditions,you will not allow a page to cached??

  • Automata:
  • Why study automata.
  • Automata practical use( compiler construction).
  • Formal description of FA and questions with each tuple of it.
  • Determinism vs non determinism.
  • Any Problem concerning languages and representations

  • DBMS
  • What are the advantages of DBMS?
  • How consistency and non-redundancy is ensured by DBMS?(Normalization)
  • What is the role of DBA?
  • Do you know SQL?
  • Queries for insertion, updating, adding attribute and changing attribute.
  • 2 Phase locking. How it ensures concurrency control?
  • What are disadvantages of 2PL?
  • Conflict serializability?

  • Computer Networks
  • Name the layers of OSI layer and explain the function of each layer.
  • What are repeaters, switches, bridges, routers, gateways?
  • What is CSMA/CD?
  • What is the distance vector routing?
  • Congestion COntrol
  • Flow Control
  • TCP/IP
  • PING,TRACERT and how they work
  • CRC,Checksum etc
  • IP layer

Must read books for the preparation



Tips for BARC interview

1 : The whole interview is technical so don't focus much on HR skills

2 : They don't look for dress or English speaking skills or your expression but yes you should be confident.

3 : Although the interview has a panel of four-five awesomely talented people and questions asked are also mediocre or tough, the environment is friendly and they provide help if you are thinking in the right direction.

4 : Prepare five subjects from GATE syllabus well and their basics should be on the tips.

5 : Prepare Sofware Engineering and one programming language well .Even if they are not in your top five.


Selection to OCES/DGFS is a two-step process:
screening to short-list potential candidates followed by interview of the short-listed candidates.

Screening for the Engineering disciplines is based on two alternative methods :

(a) GATE Score: Cutoff is set and who so ever got a GATE score above it is selected for interviews.
(b) Written Test: A written test is conducted in each of the seven Engineering disciplines (Mechanical, Chemical, Metallurgical, Electrical, Electronics, Computer and Instrumentation Engineering) except Civil Engineering for short-listing candidates for interview. Candidates who do not opt for GATE or who do not qualify on the basis of GATE Score may take the Written Test.

The screened students and then interviewed and then based on the interview final list of students is prepared.

Must read books for the preparation


BEL detailed Syllabus

Detailed syllabus of BEL Probationary Engineer (CSE) Entrance Exam

Quantitative Aptitude

  • Area
  • Average
  • Boats and Streams
  • Calendar
  • Chain Rule
  • Compound Interest
  • Data Interpretation
  • Fraction
  • Height and Distance
  • Partnership
  • Probability
  • Problems on Trains
  • Square Root and Cube Root
  • Time and Work
  • Percentage
  • Allegation of Mixture
  • Clock
  • Number Series
  • Decimals
  • Permutation and Combination
  • Pipes and Cistern
  • Problems on Ages
  • Problems on H.C.F and L.C.M
  • Profit and Loss
  • Ratio and Proportion
  • Simple Interest
  • Simplification
  • Time and Distance

General Awareness

  • Awards
  • Books and Authors
  • Economy
  • Business
  • Sports
  • Current events
  • Important Dates
  • National and International affairs
  • Important Personalities
  • Science and Technology

Reasoning Ability

  • Analogy
  • Analytical Reasoning
  • Arithmetic Reasoning
  • Blood Relation
  • Character Puzzles
  • Classification
  • Data Sufficiency
  • Direction Sense Test
  • Letter and Symbol Series
  • Logical Problems
  • Logical Sequence of Words
  • Seating Arrangement
  • Series Completion
  • Verbal Classification

General English

  • Correcting Sentences
  • Ordering
  • Word Usages
  • Comprehension
  • Verbs
  • Synonyms
  • Preposition
  • Sentence formation
  • Tenses

Technical Aptitude

Digital Logic

  • Computer Arithmetic
  • Logic functions
  • Minimization
  • Number representation
  • Computer Organization
  • Addressing modes
  • Cache memory
  • Combinational Circuits
  • Hardwired and micro-programmed control
  • I/O interface
  • Instruction pipelining
  • Machine instructions
  • Memory interface
  • Secondary storage
  • Sequential circuits
  • Serial communication

Theory of Computation

  • Context free languages
  • Finite automata
  • Pushdown automata
  • Recursively enumerable sets
  • Regular languages
  • Turing machines
  • Un-decidability

Operating Systems

  • Classical concepts
  • Concurrency
  • Deadlock
  • Processes
  • Inter-process communication
  • CPU scheduling
  • File systems
  • Protection and security
  • Synchronization
  • Threads
  • Memory management
  • I/O systems

Compiler Design

  • Code generation
  • Code Optimization
  • Lexical analysis
  • Linking
  • Parsing
  • Runtime environment
  • Syntax directed translation


  • Relational model
  • ER-model
  • Tuple calculus
  • Integrity constraints
  • Normal forms
  • File structures
  • Sequential files
  • Concurrency control
  • Relational algebra
  • Database design
  • Query languages
  • Indexing
  • Transactions

Data Structures

  • Binary search tree
  • Connected components
  • Design techniques
  • Graph
  • Hashing
  • Heap
  • List
  • Queue
  • Searching
  • Sorting
  • Stack
  • String
  • Tree
  • Spanning trees
  • Traversals in tree and graph

Computer networks

  • Application layer protocols
  • Data encoding and transmission
  • Data link control
  • Ethernet
  • Gateways
  • ISO/OSI stack
  • LAN systems and Architecture
  • Network devices
  • Network security
  • Packet switching
  • Routing protocols
  • Sliding window protocols
  • Switches
  • TCP / UDP
  • Token ring

Other than this, one can also expect questions on web technologies like HTML, JSP, XML, JSP, etc from fundamental areas of client-server computing. Students can make use of online study materials and reference books for exam preparation.

There are three rounds for the selection:

  • Written Exam/GATE EXAM
  • Technical Interview
  • HR Interview
Academic Criteria:
  • B.Tech
  • 70 % in Graduation , X and XII.
  • No backlogs.

  • Must read books for the preparation


Interview Tips

  • Dress formally

  • Listen
    Good communication skills include listening and letting the person know you heard what was said. Observe your interviewer, and match that style and pace.

  • Don't Talk Too Much
    Telling the interviewer more than he needs to know could be a fatal mistake.

  • Don't Be Too Familiar
    Your level of familiarity should mimic the interviewer's demeanour. It is important to bring energy and enthusiasm to the interview and to ask questions, but do not overstep your place as a candidate looking for the most prestigious job in the country.

  • Use Appropriate Language
    It's a given that you should use professional language during the interview. Be aware of any inappropriate slang words or references to age, race, religion, politics or sexual orientation -- these topics could send you out the door very quickly.

  • Don't miss any opportunities
    When interviewers ask for an example of a time when you did something for example, they are asking behavioural interview questions, which are designed to elicit a sample of your past behaviour. If you fail to relate a specific example, you not only don't answer the question, but you also miss an opportunity to prove your ability and talk about your skills.

  • Don't Appear Desperate
    When you interview with the "Desperate to crack" approach, you appear less confident. Reflect the three Cs during the interview: cool, calm and confidence. You know you can do the job and you have cleared previous tough rounds; make sure the interviewer believes you can, too.

Must read books for the preparation


Lateral Thinking Puzzles

Sometimes the interviewer may ask some puzzle which require thinking out of the box here are a few examples of that.

What starts with an E, ends with an E and usually contains only one letter? ENVELOPE.

Which word, if pronounced right, is wrong, but if pronounced wrong is right? Wrong!

What belongs to you but other people use it more than you? Your name!

What kind of cheese is made backwards? EDAM cheese (made backwards is edam)

Can you find a five letter word, which, when typed in upper-­-case, reads the same upside down? SWIMS.

What happens only in the middle of each month, in all of the seasons, except summer and happens only in the night, never in the day? The letter N.

If there are forty cups on the table and one cup breaks, how many tea cups are left?

We started with 4 tea cups (forty cups) and one broke.

"This is an unusual paragraph. I'm curious how quickly you can find out what is so unusual about it? looks so plain you would think nothing was wrong with it! In fact, nothing is wrong with it! It is unusual though. Study it, and think about it, but you still may not find anything odd. But if you work at it a bit, you might find out! Try to do so without any coaching!" Answer: There is no letter E anywhere in it!

In which sport do winners move backwards and losers move forwards? Tug-­-of-­-war.

What common word has 4 vowels, one after the other? Queue!

Can you name three consecutive days without using the words Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, or Sunday? Yesterday, Today, and Tomorrow!

Why are 1998 dollar coins worth more than 1997 dollar coins? Because there are more of them!

Kevin's mother has three children. The first was called Alpha, the second was called Beta. What was the name of the third? Kevin, since it was Kevin's mother and Kevin's brothers were Alpha and Beta.

What word is the same backwards and upside down? NOON. What can go up a chimney down, but can't go down a chimney up? An umbrella.

There's one sport in which neither the spectators nor the participants know the score or the leader until the contest ends. What is it? Boxing

What has roads but no cars, rivers but no water and hills but no trees? A map!

I have a large money box, 10 inches square and 12 inches tall. Roughly how many coins can I place in my empty money box? Just one, after which it will no longer be empty!

Why did the inventor of man-­-hole covers choose round ones, since square ones were easier to make? A circular cover is the only shape that cannot fall through its own hole and, therefore, cannot be accidentally dropped into the hole.

Only four words in Standard English begin with the letters "dw". Name two of them: dwarf dwell dweeb dwindle

In Aberland, you cannot take a picture of a man with a wooden leg. Why not? You cannot take pictures with a wooden leg, you use a camera.

How far can a horse run into a forest? Half way : after which it would be running out!

What does this represent: mce, mce, mce? Three Blind Mice: they have no I's!

A man looks at a photograph and says, "Brothers and sisters have I none, but this man's father is my father's son." How is the man in the photograph related to him? "My father's son" is himself (since he has no siblings), so he's saying that he is "this man's father", which means that he is looking at a photograph of his son.

A murderer is condemned to death. He has to choose between three rooms. The first is full of raging fires, the second is full of assassins with loaded guns, and the third is full of lions that haven't eaten in 3 years. Which room is safest for him? The third. Lions that haven't eaten in three years are dead.

There are two plastic jugs filled with water. How could you put all of this water into a barrel, without using the jugs or any dividers, and still tell which water came from which jug? Freeze them first. Take them out of the jugs and put the ice in the barrel. You will be able to tell which water came from which jug.

There is a mute who wants to buy a toothbrush. By imitating the action of brushing one's teeth he successfully expresses himself to the shopkeeper and the purchase is done. Now if there is a blind man who wishes to buy a pair of sunglasses, how should he express himself? He just has to open his mouth and ask!

You are running in a race. You overtake the second person. What position are you in? If your answer is first, then you are absolutely wrong! If you overtake the second person and you take his place, you are second!

If you overtake the last person, what position are you in? If you answered second last, then you are wrong again. How can you overtake the LAST person?!

Take 1000 and add 40 to it. Now add another 1000. Now add 30. Add another 1000. Now add 20. Now add another 1000. Now add 10. What is the total? Did you get 5000? The correct answer is actually 4100.

Mary's father has five daughters: 1. Nana, 2.Nene, 3. Nini, 4. Nono. What is the name of the fifth daughter? Nunu? NO! Of course not. Her name is Mary.

A man walks up to you and says : "everything I say to you is a lie." Is he telling you the truth or is he lying? He's lying. Even though he's lying when he says "everything" he says is a lie, some of the things he says can be a lie, and this is one of them.

A woman has 7 children, half of them are boys. How can this be possible? All the children are boys, so 1/2 half are boys and so is the other half.

A farmer and his hired help were carrying grain to the barn. The farmer carried one sack of grain and the hired help carried two sacks. Who carried the heavier load and why? The farmer's load was heavier. His hired help only carried two sacks, while the farmer carries one sack, but his sack is a sack of grain. The hired help only carried 2 sacks : both empty.

A boy was at a carnival and went to a booth where a man said to the boy, "If I write your exact weight on this piece of paper then you have to give me $50, but if I cannot, I will pay you $50." The boy looked around and saw no scale so he agrees, thinking no matter what the carny writes he'll just say he weighs more or less. In the end the boy ended up paying the man $50. How did the man win the bet? The man did exactly as he said he would and wrote "your exact weight" on the paper.

Must read books for the preparation



Tips for BEL interview

1 : There are two interview rounds one is purely technical and other is HR so be prepared for both

2 : If you have GATE basics right, then you can clear it easily.

3 : The interview is mainly focussed on whether you will join the company without any second thoughts if a call letter is given, and whether you are eager to learn new work.(HR)

4 : Prepare five subjects from GATE syllabus well and their basics should be on the tips.

5 : Prepare Sofware Engineering and one programming language well .Even if they are not in your top five.

Sample Interview

There were four interviewer. One interviewer acting like head, was sitting in middle.. Next right to him was a HR and next to HR was a technical person.. In the right of HEAD was another technical interviewer Head:describe yourself.

Candidate: I described my Btech,Schooling and other such stuff

M1Explain your Btech Project. Your Role in it?

Candidate : I explained it.

In middle of explanation M1 asked to write a program to display the day by getting Date from system in JSP.

HR "Who was team leader in this Project?"

Candidate: The Work load was equally divided among the teammates.

Head Tell us your favorite subjects.

CandidateCore Java1.5 & computer network.

M1 Tell the name of all layers of OSI.

Candidate I Explained with the diagram

M2 Explain TCP/IP model.

Candidate I Explained with the diagram

What is IP address?

Candidatea unique string of numbers separated by full stops that identifies each computer using the Internet Protocol to communicate over a network.

Head In which class we actually works in computer network (A, B, C, D or E)?

Candidate B

Head Tell the no of bits reserved for network address in B class.

Candidate 16 I guess

HR Tell your family bakckground?

Candidate Answered

HR Qualities of leader?

Candidate Take responsibility,think clearly,fearless,guide the team to success and motivates during failure.

HR Do you have these qualities?

Candidate Yes !!

HR Tell me one example where you had shown your leadership quality?

Candidate Explained..

HR Why less marks in fourth semester?

Candidate Explained..

HR Difference between percentage of topper and yours..

Candidate Explained..

HR What was your position in class during B.Tech?

Candidate Explained..

HR If I were ask your neighbors to describe you, what would they say?

Candidate Explained..

HR Why do you not want to Join BEL?

Candidate Explained..

HR Private companies give more money so why not BEL?

Candidate Explained..

HR Do you want to join public sector so that you get a relax job .where you don't have any work?

Candidate Explained..

HR Will you go Machlipatnam, BEL?

Candidate Explained..

HR If I give both offer (HCl & BEL), Which will you join and why?

Candidate Explained..

HR What is your opinion about moral and ethics?

Candidate Explained..

Head Tell about all phases of SDLC

Stage 1: Planning and Requirement Analysis
Stage 2: Defining Requirements
Stage 3: Designing the product architecture
Stage 4: Building or Developing the Product
Stage 5: Testing the Product
Stage 6: Deployment in the Market and Maintenance

M1 have you studied compiler Construction Subject..

Candidate Replied in positive but added that it is not my favorite.

M1 He further said "Are you comfortable with OS"?

Candidate Yes!!

M1 Explain swapping and paging and virtual memory..

Candidate Explained..

M1 What is the recommended size of paging in UNIX and on what basis we decide its size?

Candidate Explained..

Head Do you want to ask anything..

Candidate "When can I know my result?"

They replied very soon

The environment there was very cordial. Even after 35 minutes of interview I was feeling that I had been interviewed for few seconds.. Interview weigatage was 30% and written test 70%

Must read books for the preparation


IOCL Selection Process

The selection process of the company consists of 3 rounds. These rounds are as follows:
  • Written Exam
  • Technical Interview
  • HR Interview
Academic Criteria:
  • 60 percent or above in B.Tech , Class X and XII.
  • Gap of upto one year is allowed.

Exam pattern

Aptitude : 10 (Section consists of questions based on data interpretation, graphs, blood relations, statement reasoning, etc. Also, there are questions from basic mathematics like time, speed & distance, algebra, arithmetic, probability, geometry, permutation & combination, etc. Further, there are questions from English language like grammar usage, fill in the blanks, etc.)

Technical: 55 ( Syallabus same as BEL)

IOCL Interview Prep

HR Questions
1. Why did you apply for this particular job?
2. What is your greatest weakness?
3. Are you satisfied with your academic performance till date?
4. Tell me something about yourself.
5. Can you brief us about your hobbies and interests
6. Why IOCL why not BARC or ISRO?
7. Why not private companies?
8.What is team work and leadership?
9.Justify your performance in college
10.Who is your role model and why?

Technical Questions
1 - According to you which is the most important OSI layer?
2 -Can you name all the physical layers in networking?
3 -Tell me something about data mining?Where is it used? Can you tell its 3applications?
4 -Briefly describe the project that you have done in your training period?
5 - Find the only element in an array that only occurs once.
6 -Find the common elements of 2 int arrays
7 -Implement binary search of a sorted array of integers
8 - Implement binary search in a rotated array (ex. {5,6,7,8,1,2,3})
9 -Use dynamic programming to find the first X prime numbers
10 - Write a function that prints out the binary form of an int
11 - Implement parseInt
12 -Implement bubble sort
13 -Implement selection sort
14 -Implement insertion sort
15 -Implement merge sort
16 -Implement quick sort
what is database Schema?

Practice the Questions Mentioned in Sample Questions tab

Must read books for the preparation


ISRO Preparation

Old ISRO Exam Papers

  • ISRO - 2008

  • ISRO - 2009

  • ISRO - 2011

  • ISRO - 2013

  • ISRO - 2014

  • ISRO Selection Process

    The candidate should have First Class with minimum 65% marks in the Qualifying Degree ie, BE/B.Tech or equivalent.
    The written test will then be conducted in various cities.
    Based on the performance in the Written Test, candidates will be short-listed for interview.
    Written test is only a first level screening and written test score will not be considered for final selection process.
    Final selection will be based on the performance of the candidates in the Interview and those who secure minimum 60% marks in the interview will be eligible for consideration for empanelment in the selection panel, in the order of merit.

    ISRO Syllabus

    • Digital Logic: Logic functions, Minimization, Design and synthesis of Combinational and Sequential circuits -- Number representation and Computer Arithmetic (fixed and floating point)
    • Computer Organization: Machine instructions and addressing modes, ALU and Data-path, hardwired and micro-programmed control, Memory interface, I/O interface (Interrupt and DMA mode), Serial communication interface, Instruction pipelining, Cache, main and secondary storage.
    • Data structures: Notion of abstract data types, Stack, Queue, List, Set, String, Tree, Binary search tree, Heap, Graph --
    • Programming: C programming, Program control (iteration, recursion, Functions), Scope, Binding, Parameter passing, Elementary concepts of Object oriented, Functional and Logic Programming --
    • Algorithms: Tree and graph traversals, Connected components, Spanning trees, Shortest paths -- Hashing, Sorting, Searching -- Design techniques (Greedy, Dynamic Programming, Divide-and-conquer) --
    • Compiler Design: Lexical analysis, Parsing, Syntax directed translation, Runtime environment, Code generation, Linking (static and dynamic) --
    • Operating Systems: Classical concepts (concurrency, synchronization, deadlock), Processes, threads and Inter-process communication, CPU scheduling, Memory management, File systems, I/O systems, Protection and security.
    • Databases: Relational model (ER-model, relational algebra, tuple calculus), Database design (integrity constraints, normal forms), Query languages (SQL), File structures (sequential files, indexing, B+ trees), Transactions and concurrency control --
    • Computer Networks: ISO/OSI stack, sliding window protocol, LAN Technologies (Ethernet, Token ring), TCP/UDP, IP, Basic concepts of switches, gateways, and routers.

    ISRO Interview Questions Asked in 2016

    Following is a list of frequently asked questions that were asked (at Delhi center) in ISRO interviews for Computer Science.
    • Why do you want to join ISRO?
    • Tell me something about your old job/Mtech (if applicable)
    • What are your favourite subjects. (they will ask questions from any subject they like not necessarily these)
    • How good are you in Maths? (they expect the answer to be YES)
    • What is the formula for sum of n terms of a GP
    • What is the condition on r if the sum is till infinity
    • Proof Pythagoras theorem
    • Proof (a+b)2 using geometry
    • Write an algorithm on the whiteboard behind you for finding the square root of a number and demonstrate your algorithm to find the solution of 16 i.e. 4 (they want to check if you are strong in Numerical Analysis subject and handle pressure situation with ease)
    • What is a Core in a CPU?
    • What is a multi core CPU?
    • Which condition is better : having 4 different CPUs or having 4 cores in a single CPU?(Many counter questions in this question)
    • What is parallelism?
    • What is pipelining?
    • How is pipelining achieved?
    • Instruction level parallelism?
    • Use of stacks.(or any other data structure)
    • Which is better RISC or CISC
    • Difference between any two OSs. ( windows/Mac or Windows/linux etc)
    • What is paging,segmentation and belady anomaly
    • Which OS do you use and why?
    • How can you make an app for both IOS and android?(if you have projects related to android in your resume)
    • Tell us about your Btech Project.(and every detail regarding it in form of counter questions.)
    • Can you tell us about Turing machines. (if Automata is mentioned in favorite subjects then only such questions are asked)
    • What are repeaters, switches, bridges, routers and gateways? Explain routing or forwarding in these devices? How are LANs connected?
    • ACID properties?
    • What is Graph database
    • How consistency and non-redundancy is ensured by DBMS?(Normalization and all questions related to normalisation may be asked if DBMS is in your favourites)
    • What are the advantages of DBMS?
    • Egg Break problem?
    • Questions from circles in maths like formulae for circumference, radius or questions to find an angle in a given circle.
    • Difference between any sorting algorithms?
    • Draw graph on the whiteboard for ex, log x and some trigonometric functions.
    • Other Questions can be checked in Sample Questions in PSUs Tab

    ISRO Interview Tips

    • If prepared for GATE then the round will sound easy.
    • Questions were mainly from major subjects of computer science namely Automata, OS, Algorithms.
    • Questions would be about your CV and the projects that you have done so be prepared.

    Words from an Interviewee

    The interview started at 9'o clock I am the third person for the interview.I had my seat they told me to introduce yourself and tell about your college and education.

    The interview started with some basic questions of computer science like Digitals,OS,C,C++ and Automata.

    The Interviewer ask basic questions, practical knowledge about all the concepts and what you learnt in Btech or postgrad. Mostly they stressed on college projects.

    I was very confident and used the board to explain certain answers.They also asked some coding questions on strings and pointers. In the Interview, I answered only 70% questions with confidence. Try to give answers citing some examples and if you don't know the answer then tell them Sir I don't know instead of tricking them with words.

    Must read books for the preparation


All About NIELIT

NIELIT Question Paper Scheme

  • The Written Examination shall be Objective type and OMR based.
  • There will be total of 120 objective type Questions consisting of 60 questions from Computer Science and 60 questions on Generic Area. The Generic Area will comprise of Logical, Analytical Reasoning Capabilities, Quantitative and Qualitative abilities and General Awareness and Aptitude.
  • Every Question will carry 1 (one) mark and there will be negative marking of 0.25 mark for each wrong answer.

NIELIT Selection Process

  • The final selection of eligible candidates for appointment to the post of Scientist-"B" will be based on the combined performance of the candidates both in the written examination and in interview. The weight-age of marks for written examination and interview will be in the ratio of 85:15. It is mandatory to appear in the interview for selection.
  • Only the shortlisted candidates for the post of Scientist "B" (based on merit position and reservation policy etc.), who have qualified the written examination, will be called for interview.
  • For the post of Scientific/Technical Assistant "A" there will be no interview.
  • Verification of requisite documents will be done at the time of the interview for the post of Scientist-"B". For the post of Scientific/ Technical Assistant "A" verification of documents will be done before joining.

Must read books for the preparation