Computer and ICT Basics
Topics covered
Introductory computer questions test hardware and software basics, number systems, memory units, input-output devices, operating systems, internet concepts, and basic office applications.
Core concepts
Hardware: CPU (ALU, control unit, registers), primary memory (RAM volatile, ROM non-volatile), secondary storage (HDD, SSD), and peripherals. Memory units: 1 byte = 8 bits; 1 KB = 1024 bytes; 1 MB = 1024 KB; 1 GB = 1024 MB; 1 TB = 1024 GB. Number systems: binary, octal, decimal, hexadecimal; practise conversion between binary and decimal. Software: system software (OS, utilities) vs application software. Internet: IP address, URL, HTTP/HTTPS, browser, search engine, email protocols. Office: spreadsheet formulas, cell references, and word-processing basics.
Common traps
Confusing bits and bytes; assuming 1 KB = 1000 bytes (in most exam contexts it is 1024); mixing ROM with RAM; confusing the internet with the World Wide Web; and misidentifying which device is input vs output (a touchscreen is both). In number-system conversion, forgetting to read remainders in reverse order when converting decimal to binary.
Worked example
Convert decimal 13 to binary. 13 ÷ 2 = 6 remainder 1; 6 ÷ 2 = 3 remainder 0; 3 ÷ 2 = 1 remainder 1; 1 ÷ 2 = 0 remainder 1. Reading remainders bottom-up: 1101. Check: 8 + 4 + 0 + 1 = 13. Rule of thumb: divide repeatedly by the base and read remainders in reverse.
Practice habit
Memorise the 1–16 binary table and the power-of-two values up to 2¹⁰.