Computer Fundamentals and Networking Basics
Computer Fundamentals and Networking Basics
This domain tests hardware, operating systems, number systems, networking models, IP addressing and basic cyber hygiene. Questions are often definitional but include small calculations.
Core rules
- Units: 1 byte = 8 bits; 1 KB = 1024 bytes in binary convention; distinguish MB (megabyte) from Mb (megabit).
- CPU: ALU performs arithmetic/logic; control unit directs; registers hold current data.
- Memory: RAM is volatile; ROM is non-volatile.
- OS: manages processes, memory, files and devices; provides a user interface.
- OSI: Physical, Data Link, Network, Transport, Session, Presentation, Application. TCP/IP collapses these into four layers.
- IP: IPv4 is 32-bit; IPv6 is 128-bit. Private ranges are 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16; loopback is 127.0.0.1.
- Devices: hub = Layer 1; switch = Layer 2; router = Layer 3.
- Protocols: DNS resolves names; DHCP assigns addresses; TCP is connection-oriented; UDP is connectionless.
Worked example
Convert 1101₂ to decimal: 1×2³ + 1×2² + 0×2¹ + 1×2⁰ = 8 + 4 + 0 + 1 = 13. A /24 IPv4 network has 2⁸ = 256 addresses, of which 254 are usable after network and broadcast addresses.
Traps
Mixing bits and bytes; calling a switch a Layer 3 device; confusing TCP with UDP; using public IP ranges as private; forgetting to subtract two usable hosts in a subnet; and treating phishing as a hardware fault.