IT Fundamentals and Computer Hardware
Domain 1 tests whether you can map a symptom to the hardware component responsible and reason about capacity, speed and volatility rather than recite shopping specifications.
Core blocks
- CPU - cores run threads concurrently; clock speed is cycles per second, but cache size and instructions-per-clock often matter more. L1/L2 cache is per core, L3 is shared.
- RAM vs storage - RAM is volatile working memory; storage is non-volatile. SSD: fast random I/O, finite write endurance, no moving parts. HDD: cheaper per terabyte, strong for sequential bulk.
- Firmware - BIOS/UEFI initialises hardware, runs POST, then hands off to the bootloader. POST failure appears as beep codes, diagnostic LEDs or no display.
- Power and ports - the PSU must cover peak CPU plus GPU draw with headroom. USB-C is a connector, not a speed: it may carry USB 2.0, USB4, Thunderbolt or DisplayPort.
Worked example
A user says "my PC is slow, I need a bigger hard drive." Task Manager shows disk at 100% and 8 GB RAM with 6 GB in use, so the machine is paging. Reasoning: extra capacity would not reduce latency, because the bottleneck is memory pressure plus slow random reads. More RAM removes the paging and an SSD cuts the wait. Diagnose the bottleneck before recommending any purchase.
Traps that cost marks
- Treating "memory" as storage - a 128 GB phone has 128 GB of storage, not RAM.
- Mixing GB (10^9 bytes) with GiB (2^30); a 1 TB drive reports about 931 GiB.
- Assuming more cores always helps; single-threaded work gains little.
- Confusing throughput (MB/s) with capacity (TB).