Computer Fundamentals and Hardware
What this domain tests
Computer Fundamentals and Hardware covers the stored-program model, CPU organisation, memory hierarchy, motherboard components, ports and storage. Questions often ask you to distinguish primary from secondary memory, identify a device by function, or calculate capacity and addressable memory.
Core rules
- Von Neumann cycle: fetch → decode → execute → write back. The program counter holds the next instruction address; the instruction register holds the current instruction.
- Memory: RAM is volatile and holds programs/data in use; ROM is non-volatile firmware. Cache is faster and smaller than RAM; secondary storage is persistent.
- Buses: address bus carries addresses (width limits addressable locations), data bus carries contents, control bus carries read/write and timing signals.
- Capacity: 1 byte = 8 bits; 1 KiB = 2^10 bytes; 1 MiB = 2^20 bytes; 1 GiB = 2^30 bytes.
- Ports: USB, HDMI, VGA, Ethernet, audio; input devices send data in, output devices present results.
Worked example
A machine has a 32-bit address bus and byte-addressable memory. Addressable locations = 2^32 = 4,294,967,296 bytes = 4 GiB. If RAM is advertised as 4 GB using decimal units, that is 4,000,000,000 bytes, slightly less than 4 GiB. The reasoning: address-bus width gives the number of distinct addresses; byte addressing means one address selects one byte.
Traps
Do not call ROM volatile or cache a replacement for disk. Do not mix GB (10^9) with GiB (2^30). A faster clock does not by itself guarantee faster execution; cores, cache and instruction mix matter. Firmware is software stored in hardware.