Preparing for the ISRO Technical Assistant (Computer Science) examination? Solving previous year question papers is one of the most effective ways to understand the examination pattern, identify important computer science subjects and improve problem-solving skills.
The ISRO Technical Assistant Computer Science Previous Year Question Paper 2021 is a valuable practice resource for candidates preparing for technical recruitment examinations conducted by the Indian Space Research Organisation (ISRO).
This question paper contains 80 multiple-choice questions covering several important areas of Computer Science and Information Technology, including Data Structures, Algorithms, Operating Systems, Computer Networks, Database Management Systems, Computer Architecture, Programming Languages, Digital Logic, Software Engineering and Mathematics.
Unlike examinations that focus mainly on theoretical definitions, this paper includes conceptual questions, programming output problems, numerical calculations, algorithm-based problems and practical applications of computer science fundamentals.
In this article, you can download the ISRO Technical Assistant Computer Science question paper PDF, understand the complete subject-wise coverage, explore important topics, analyse the question types and prepare an effective strategy for upcoming ISRO examinations.
ISRO Technical Assistant Computer Science Question Paper 2021 – PDF Download
Candidates preparing for ISRO Technical Assistant Computer Science recruitment can use the previous year question paper to practise actual examination-style questions.
| Exam Information | Details |
|---|---|
| Organisation | Indian Space Research Organisation (ISRO) |
| Post Name | Technical Assistant |
| Discipline | Computer Science |
| Post Number | 1427 |
| Paper Language | English and Hindi |
| Question Type | Multiple Choice Questions (MCQs) |
| Total Questions | 80 |
| Available Resource | Previous Year Question Paper PDF |
ISRO Technical Assistant Computer Science Exam Analysis
The question paper covers a broad range of Computer Science subjects. It tests both fundamental knowledge and the ability to solve technical problems.
The following are the major subject areas identified from the 80 questions.
1. Data Structures and Algorithms
Data Structures and Algorithms are important areas of this paper. Several questions require candidates to understand data organisation, searching techniques, sorting algorithms, tree operations and algorithmic complexity.
Important topics covered include:
- Binary Search Tree (BST)
- AVL Tree and Tree Rotations
- Hashing and Collision Resolution
- Linear Probing
- Bubble Sort
- Heap and Max-Heap
- Stack Operations
- Circular Linked Lists
- Binary Tree Traversals
- Merge Sort
- Minimum Spanning Tree
- Shortest Path Algorithms
- Greedy Algorithms
- Dynamic Programming
- Backtracking
Examples of questions from the paper:
- Question 2: Hash table insertion using a given hash function and linear probing.
- Question 4: Finding the postorder traversal from a given BST preorder traversal.
- Question 8: Identifying Bubble Sort from a given C++ program.
- Question 12: Identifying impossible search sequences in a Binary Search Tree.
- Question 13: Calculating single and double rotations in an AVL Tree.
- Question 70: Converting an array into a Max-Heap.
- Question 72: Matching algorithms with their design techniques.
- Question 80: Calculating comparisons required for optimal merging of sorted sequences.
Preparation Focus: Practise tree construction, AVL rotations, hashing, heap operations, sorting complexity, stack permutations and algorithm design techniques. Do not restrict your preparation to algorithm definitions.
2. C and C++ Programming
Programming fundamentals are another important part of the examination. Questions test the understanding of programming language concepts and the ability to analyse code without executing it.
Important topics include:
- C and C++ fundamentals
- Constructors and Destructors
- Default Constructor
- Copy Constructor
- Inline Functions
- Virtual Functions
- Runtime Polymorphism
- Function Overloading
- Operator Overloading
- Pointers and Pointer Arithmetic
- Arrays and Pointers
- Function Arguments
- Recursion
- Switch Statements
- Control Flow
- Output Prediction
Examples from the question paper:
- Question 1: Identifying the nature of
coutin C++. - Question 3: Identifying an operator that cannot be overloaded.
- Question 5: Understanding the default constructor.
- Question 6: Identifying inline functions.
- Question 7: Understanding runtime polymorphism.
- Questions 25–31: Predicting the output of C programs involving pointers, arrays, functions and pointer arithmetic.
Preparation Focus: Give special attention to pointers, arrays, recursion, function calls, object-oriented programming and code-output questions. Practise tracing programs line by line.
3. Operating Systems
Operating Systems is an important subject for technical recruitment examinations. The paper includes questions from process scheduling, memory management, virtual memory and disk scheduling.
Important topics include:
- CPU Scheduling
- Shortest Job First (SJF)
- Process Scheduling
- Waiting Time Calculation
- Pipeline and Process Dependencies
- Demand Paging
- Page Faults
- Memory Allocation
- Best Fit and Worst Fit
- Thread Pool
- Deadlock and Process Management Concepts
- Disk Scheduling
- Shortest Seek Time First (SSTF)
Examples from the paper:
- Question 32: Performance problems in pipeline processors.
- Question 33: Average waiting time using non-preemptive SJF.
- Question 34: Calculating page faults in a demand paging system.
- Question 35: Total head movement using SSTF disk scheduling.
- Question 37: Understanding the advantages and disadvantages of thread pools.
- Question 38: Memory allocation using Best Fit and Worst Fit policies.
Preparation Focus: Practise CPU scheduling numerical problems, page replacement and page fault calculations, disk scheduling algorithms and memory allocation problems. Understand the difference between preemptive and non-preemptive scheduling.
4. Computer Organization and Architecture
Computer Organization and Architecture is another significant technical area. The paper tests knowledge of processor design, cache memory, instruction execution and memory organisation.
Important topics include:
- RISC Architecture
- Harvard Architecture
- Von Neumann Architecture
- Instruction Pipeline
- Pipeline Stages
- Pipeline Hazards
- Cache Memory
- Cache Mapping Techniques
- Set-Associative Mapping
- Direct Mapping
- LRU Replacement
- Memory Addressing
- RAM Organisation
- Interrupt Handling
- Interrupt Service Routine
- Immediate Operand Calculation
- Full Adder
Examples from the paper:
- Question 39: Calculating tag bits in a set-associative cache.
- Question 43: Calculating the maximum immediate operand value.
- Question 47: Identifying characteristics of RISC processors.
- Question 48: Calculating total clock cycles in an instruction pipeline.
- Question 51: Calculating propagation delays in a full adder.
- Question 52: Identifying the architecture that uses separate data and instruction buses.
- Question 53: Understanding CPU interrupt handling.
- Question 55: Calculating the number of RAM chips required for a memory system.
- Questions 56–58: Cache mapping, LRU and virtual memory.
Preparation Focus: Focus on cache memory numerical problems, address calculations, instruction pipeline performance, RISC architecture, interrupts and memory organisation.
5. Computer Networks
Computer Networks questions cover networking protocols, routing, data transmission, error detection and TCP mechanisms.
Important topics include:
- TCP and UDP
- TCP Congestion Control
- TCP Window Size
- Network Throughput
- Routing Tables
- IP Addressing
- Subnet Masks
- Ethernet
- Bandwidth and Latency
- Data Transmission Time
- Error Detection
- Cyclic Redundancy Check (CRC)
- Hamming Code
- SSL Handshake
- SMTP and PPP
- OSI Reference Model
Examples from the paper:
- Question 21: Understanding Hamming Distance and error detection/correction.
- Question 42: Identifying network topology.
- Question 63: Arranging SSL handshake steps in the correct order.
- Question 65: Matching networking protocols with OSI layers.
- Question 66: Calculating TCP throughput using window size and round-trip time.
- Question 67: Finding the correct router interface using a routing table.
- Question 68: Calculating file transmission time.
- Question 69: Understanding TCP congestion avoidance.
- Question 71: Identifying error detection techniques at the data link layer.
Preparation Focus: Practise subnetting, routing table problems, TCP throughput, transmission delay, propagation delay, error detection and OSI layer-based questions.
6. Database Management Systems (DBMS)
DBMS is an essential subject for Computer Science recruitment examinations. The paper includes SQL query interpretation, relational algebra, database constraints, indexing and transaction management.
Important topics include:
- Relational Database Model
- Primary Key and Foreign Key
- Referential Integrity
- SQL Queries
- SQL Joins
- INTERSECT Operation
- Aggregate Functions
- GROUP BY and HAVING
- Nested Queries
- Database Indexing
- B+ Tree Index
- Clustered and Unclustered Index
- Transaction Management
- Database Recovery
- Join Operations
Examples from the paper:
- Question 73: Maximum and minimum size of a relational join.
- Question 74: Referential integrity constraints involving primary and foreign keys.
- Question 75: Understanding SQL INTERSECT queries.
- Question 76: Identifying conditions that may cause irrecoverable database errors.
- Question 77: Analysing GROUP BY and HAVING clauses.
- Question 78: Writing a query to identify theatres with maximum capacity.
- Question 79: Selecting an appropriate database index for a query.
Preparation Focus: Practise SQL queries, joins, subqueries, aggregate functions, indexing and transaction schedules. Pay particular attention to query-based questions rather than memorising SQL syntax alone.
7. Mathematics and Discrete Mathematics
The paper also contains mathematical and analytical questions that require logical reasoning and numerical problem-solving.
Important topics include:
- Probability
- Relative Error
- Linear Algebra
- Matrices
- Eigenvalues
- Null Space
- Column Space
- Matrix Inverse
- Series
- Number Systems
- Mathematical Expressions
- Binary and Base Conversion
Examples from the paper:
- Question 9: Relative error calculation.
- Question 10: Properties of invertible matrices.
- Question 11: Probability of obtaining two heads in three coin tosses.
- Question 14: Evaluation of an infinite series.
- Question 15: Sum and product of eigenvalues.
- Question 16: Properties of a rotation matrix.
- Question 18: Properties of inverse matrices.
- Question 23: Number system and base conversion.
Preparation Focus: Revise probability, matrices, eigenvalues, number systems and basic mathematical concepts. Practise numerical questions to improve calculation speed.
8. Software Engineering and Compiler Design
The paper also tests software development concepts and compiler-related fundamentals.
Important topics include:
- Software Testing
- Error Seeding
- Estimation of Undetected Errors
- Cyclomatic Complexity
- Compiler Phases
- Syntax Checking
- Type Checking
- Symbol Table Management
- Runtime Memory Allocation
- Algorithm Analysis
Examples from the paper:
- Question 45: Estimating undetected software errors using seeded errors.
- Question 46: Calculating cyclomatic complexity after sequential integration of modules.
- Question 49: Identifying activities not performed during compilation.
Preparation Focus: Understand software testing techniques, error estimation, McCabe’s cyclomatic complexity, compiler phases and the distinction between compile-time and runtime activities.
9. Digital Logic and Boolean Algebra
Digital Logic questions test the fundamentals of logic gates, Boolean expressions and digital circuit design.
Important topics include:
- Boolean Algebra
- Boolean Expression Simplification
- Logic Gates
- Half Adder
- Full Adder
- Propagation Delay
- Combinational Circuits
- Logic Circuit Interpretation
Examples from the paper:
- Question 51: Full adder implementation and propagation delays.
- Question 59: Simplifying a Boolean expression.
- Question 60: Identifying the Boolean function represented by a logic circuit.
Preparation Focus: Practise Boolean algebra simplification, truth tables, logic gates and combinational circuit problems.
Most Important Topics to Focus on for ISRO Technical Assistant Computer Science
Based on the coverage of this question paper, candidates should prioritise the following topics while preparing for future examinations.
| Subject | High-priority topics |
|---|---|
| Data Structures | Trees, BST, AVL, Hashing, Heap, Stack |
| Algorithms | Sorting, Searching, Greedy, Dynamic Programming |
| C/C++ | Pointers, Recursion, OOP, Output Questions |
| Operating Systems | CPU Scheduling, Paging, Disk Scheduling |
| Computer Architecture | Cache, Pipeline, RISC, Memory |
| Computer Networks | TCP, Routing, Subnetting, CRC |
| DBMS | SQL, Joins, Indexing, Transactions |
| Mathematics | Probability, Matrices, Eigenvalues |
| Software Engineering | Testing, Cyclomatic Complexity |
| Digital Logic | Boolean Algebra, Adders, Logic Gates |
These priorities are based on the topics appearing in the uploaded paper. They should not be interpreted as a guaranteed topic-wise weightage for future ISRO examinations.
What Type of Questions Are Asked in the ISRO Technical Assistant Exam?
The paper demonstrates that candidates need more than theoretical knowledge. Questions can broadly be classified into the following categories.
1. Conceptual Questions
These questions test fundamental knowledge of Computer Science.
Examples:
- What is a virtual function?
- Which operator cannot be overloaded in C++?
- Which architecture uses separate instruction and data buses?
- What is the role of a page table?
2. Numerical Questions
These questions require calculations and the application of formulas.
Examples:
- CPU scheduling waiting time.
- Page fault calculation.
- Disk head movement.
- Cache tag bits.
- TCP throughput.
- Transmission time.
- Probability and matrix calculations.
3. Programming Output Questions
Candidates must analyse the given program and identify its output.
Examples:
- Pointer arithmetic.
- Array indexing.
- Recursion.
- Switch-case execution.
- Function arguments.
- C and C++ programming behaviour.
4. Algorithm-Based Questions
These questions require candidates to execute or understand an algorithm.
Examples:
- BST traversal.
- AVL rotations.
- Hash table insertion.
- Heap construction.
- Sorting and merging algorithms.
5. SQL and Database Questions
Candidates need to understand relational database concepts and evaluate SQL queries.
Examples:
- SQL INTERSECT.
- GROUP BY and HAVING.
- Nested queries.
- Referential integrity.
- Database indexing.
Preparation Strategy for Upcoming ISRO Technical Assistant Examinations
Candidates should follow a structured preparation strategy instead of studying subjects randomly.
Step 1: Build Strong Fundamentals
Start with the core Computer Science subjects:
- Data Structures and Algorithms
- Operating Systems
- DBMS
- Computer Networks
- Computer Organization and Architecture
- C and C++ Programming
Understand the basic concepts before attempting advanced numerical problems.
Step 2: Practise Previous Year Questions
Solve previous year questions from ISRO and other technical recruitment examinations.
Practising PYQs helps you:
- Understand question patterns.
- Identify frequently tested concepts.
- Improve numerical problem-solving.
- Recognise common programming mistakes.
- Evaluate your preparation level.
Step 3: Focus on Numerical and Programming Questions
Do not ignore calculation-based questions.
Practise at least a few problems daily from:
- CPU Scheduling
- Cache Memory
- Computer Networks
- Probability
- Matrices
- Algorithms
- Pointer Arithmetic
Step 4: Attempt Subject-Wise Mock Tests
After completing each subject, attempt a subject-wise test to evaluate your understanding.
For example:
- Data Structures and Algorithms Mock Test
- Operating Systems Mock Test
- DBMS Mock Test
- Computer Networks Mock Test
- Computer Architecture Mock Test
- C and C++ Programming Mock Test
Step 5: Attempt Full-Length Mock Tests
After completing the syllabus, practise full-length mock examinations under timed conditions.
Analyse incorrect answers and revise the concepts behind them. Focus on improving accuracy, speed and time management.
Practise ISRO Computer Science Previous Year Questions and Mock Tests
Along with downloading the question paper, candidates should practise topic-wise MCQs and full-length mock tests.
CSE Study247 provides Computer Science preparation resources for candidates preparing for technical recruitment examinations.
You can explore:
- Computer Science Previous Year Questions.
- Data Structures and Algorithms MCQs.
- Operating Systems Practice Tests.
- DBMS MCQs and SQL Questions.
- Computer Networks Practice Questions.
- Computer Organization and Architecture MCQs.
- C and C++ Programming Questions.
- Full-Length Computer Science Mock Tests.
[Explore Computer Science Practice Tests – https://csestudy247.com/practice-test/]
Regular practice will help candidates identify weak areas and improve their overall examination preparation.
Frequently Asked Questions (FAQs)
1. Where can I download the ISRO Technical Assistant Computer Science Question Paper PDF?
You can download the question paper using the PDF download link provided in this article. The uploaded paper is for Technical Assistant (Computer Science), Post No. 1427.
2. How many questions are included in the ISRO Technical Assistant Computer Science paper?
The provided question paper contains 80 multiple-choice questions.
3. Which subjects are important for ISRO Technical Assistant Computer Science preparation?
Important subjects include Data Structures, Algorithms, Operating Systems, DBMS, Computer Networks, Computer Architecture, C/C++ Programming, Mathematics, Software Engineering and Digital Logic.
4. Are numerical questions included in the ISRO Technical Assistant examination?
Yes. The uploaded paper includes numerical problems involving CPU scheduling, page faults, disk scheduling, cache memory, TCP throughput, transmission time, probability and matrices.
5. Is C and C++ programming important for ISRO Technical Assistant preparation?
Yes. The paper contains questions on C++ concepts, constructors, virtual functions, pointers, arrays, recursion and program output prediction.
6. How should I prepare for the ISRO Technical Assistant Computer Science examination?
Build strong fundamentals in core Computer Science subjects, solve previous year questions, practise numerical problems, attempt subject-wise mock tests and regularly analyse your mistakes.
7. Should I solve previous year question papers for ISRO preparation?
Yes. Previous year papers are useful for understanding question styles, identifying important concepts and improving problem-solving speed.
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