The CPU (Central Processing Unit) is the brain that executes instructions. RAM (Random Access Memory) provides temporary storage for running programs. ROM (Read Only Memory) stores permanent instructions like BIOS. Storage devices like hard drives and SSDs keep data permanently.
Input devices include keyboard and mouse. Output devices include monitor and printer
First generation (1940s-1950s) used vacuum tubes. Second generation (1950s-1960s) used transistors. Third generation (1960s-1970s) used integrated circuits. Fourth generation (1970s-present) uses microprocessors.
Fifth generation (present-future) focuses on artificial intelligence. Memory Units
SSC CGL frequently asks about computer generations, memory units conversion, basic components, and famous personalities in computing. Questions often test the difference between RAM and ROM, input-output devices classification, and historical developments. Memory Conversion Shortcut: Remember the sequence - Bit, Byte, KB, MB, GB, TB. Each step multiplies by approximately 1000 (exactly 1024). For quick calculations, use 1000 instead of 1024 for rough estimates.
Use the conversion 1 GB = 1024 MB
Divide 2048 by 1024
2048 ÷ 1024 = 2
Therefore, 2048 MB = 2 GB Another quick method: Since 2048 = 2 × 1024, we get 2 GB directly. Operating System Basics: Windows, Linux, and MacOS are popular operating systems. They manage hardware resources, provide user interface, and run applications. DOS (Disk Operating System) was an early command-line system. Network Fundamentals: LAN (Local Area Network) connects computers in small areas. WAN (Wide Area Network) covers large geographical areas. Internet is the largest WAN. Protocols like TCP/IP govern data transmission. Programming Languages: Machine language uses binary code. Assembly language uses mnemonics. High-level languages like C, Java, and Python are human-readable. Compilers convert high-level code to machine code.
Students often confuse RAM with storage capacity. RAM is temporary memory that gets erased when power is off. Storage (hard drive) is permanent memory that retains data.
Also, many mix up input and output devices - remember input goes INTO the computer, output comes OUT of it.
15graded MCQs · easy to hard · full solution & trap analysis