Computer Knowledge and Basics
Fundamentals
- Computer generations: first used vacuum tubes, the fifth is associated with artificial intelligence.
- Hardware versus software; system software versus application software.
- CPU = ALU + control unit + registers; RAM is volatile, ROM is non-volatile.
- Memory units: 1 byte = 8 bits; 1 KB = 1024 bytes; 1 MB = 1024 KB.
Office tools and shortcuts
- Word: Ctrl+S save, Ctrl+P print, Ctrl+Z undo, Ctrl+F find.
- Excel: every formula begins with =; cells are referenced like A1; common functions are SUM, AVERAGE, IF.
- PowerPoint: F5 starts the slide show.
Internet and security
- URL, HTTP versus HTTPS (secure), browser, search engine, email fields To/Cc/Bcc.
- Network types LAN and WAN; an IP address identifies a device on a network.
- Threats include virus, worm, phishing and ransomware; a firewall filters incoming and outgoing traffic.
Worked example
Convert binary 1101 to decimal. Expand from the rightmost bit, which is 2⁰: 1×8 + 1×4 + 0×2 + 1×1 = 8 + 4 + 0 + 1 = 13.
Traps that cost marks
- Choosing 1000 bytes for 1 KB - the standard exam answer is 1024.
- Claiming RAM stores data permanently; it is ROM that retains data without power.
- Confusing Cc (visible copy) with Bcc (hidden copy).
- Treating a compiler and an interpreter as the same thing.
- Mixing input devices (keyboard, scanner) with output devices (monitor, printer).