Computer Hardware
Computer Hardware tests your knowledge of what sits inside the system unit, how the memory hierarchy works, which port carries which signal, and whether you can diagnose a performance complaint logically instead of guessing.
Inside the system unit
- CPU: ALU performs arithmetic and logic, CU fetches–decodes–executes, registers hold the operands in use. Clock speed is in GHz; each core is an independent processing unit.
- Motherboard: sockets, chipset, RAM slots, PCIe expansion slots, firmware (BIOS/UEFI).
- Memory hierarchy fastest to slowest: registers → cache → RAM → SSD/HDD.
- RAM is volatile and holds running programs; ROM is non-volatile and holds startup firmware.
- Storage: HDD is magnetic with moving platters; SSD is flash with no moving parts.
- SMPS converts AC mains to regulated DC; a UPS stores energy in batteries and supplies backup AC - different devices.
- Ports: USB, HDMI (digital video + audio), VGA (analog video), RJ-45 Ethernet, 3.5 mm audio.
- Peripherals: input (keyboard, scanner, mic), output (monitor, printer, speaker), both (touchscreen, modem).
Worked example
A laptop with 500 GB free disk slows to a crawl when 20 browser tabs are open. Diagnosis: RAM is exhausted, so the OS pages data to disk (swap), which is far slower than memory. Fix: add RAM, not disk. Reasoning: free disk affects storage capacity, not how many programs stay resident in memory.
Traps that cost marks
- Saying RAM stores files permanently or that ROM is volatile.
- Confusing cache size with RAM size.
- Describing a UPS as a converter - it also stores energy.
- Mixing HDMI (digital) with VGA (analog).