Computer Science Quick Revision
Key concepts, definitions, and important points for computer science competitive exams
Select Revision Category
Topic-wise Revision Points
Computer Fundamentals
- Generation of computers (1st to 5th)
- Types of computers (Analog, Digital, Hybrid)
- Input/Output devices and their functions
- Memory hierarchy (Registers, Cache, RAM, ROM, Secondary)
Operating Systems
- Functions of OS (Process management, Memory management, File management)
- Types of OS (Batch, Time-sharing, Distributed, Real-time)
- Process states (New, Ready, Running, Waiting, Terminated)
- Scheduling algorithms (FCFS, SJF, Round Robin, Priority)
Programming Concepts
- Data types (Primitive, Non-primitive)
- Control structures (Sequence, Selection, Iteration)
- OOP concepts (Encapsulation, Inheritance, Polymorphism, Abstraction)
- Algorithm complexity (Big O notation)
Networking
- OSI model layers (7 layers with functions)
- TCP/IP model
- Network devices (Hub, Switch, Router, Gateway)
- IP addressing (IPv4 classes, subnetting)
Database Management
- DBMS vs RDBMS
- Normalization (1NF, 2NF, 3NF, BCNF)
- SQL commands (DDL, DML, DCL, TCL)
- Keys (Primary, Foreign, Candidate, Super)
Memory Aids & Mnemonics
OSI Model: Please Do Not Throw Sausage Pizza Away (Physical, Data Link, Network, Transport, Session, Presentation, Application)
TCP/IP Model: Army Navy (Application, Transport, Internet, Network Access)
Computer Generations: Vacuum Tubes, Transistors, ICs, Microprocessors, AI
Important Formulas & Rules
CPU Utilization = 1 - pⁿ (where p = I/O wait probability, n = number of processes)
Throughput = Number of processes completed / Time unit
Turnaround Time = Completion Time - Arrival Time
Waiting Time = Turnaround Time - Burst Time
Revision Strategy
First Pass (30 minutes)
Quickly scan all topics. Identify areas where you feel less confident. Mark them for focused revision.
Deep Revision (60 minutes)
Study marked topics thoroughly. Write down key points. Create your own mnemonics for difficult concepts.
Practice (45 minutes)
Solve 10-15 questions from this category. Apply the formulas and techniques you just revised.
Final Review (15 minutes)
Go through mnemonics and formulas one more time. Note down any remaining doubts for later clarification.