Hardware, software and operating systems
What this domain covers
This domain covers the components of a computer system and how software and operating systems manage them. Candidates should know the roles of CPU, RAM, storage (HDD, SSD, NVMe), motherboard, PSU, GPU and peripherals, and the input-process-output-storage model. Understand the fetch-decode-execute cycle, cache and virtual memory, and why RAM is volatile. On the software side, know the difference between system software (operating systems, drivers, utilities) and application software, and the functions of an operating system: process and memory management, file systems, device drivers, user management, security and interfaces.
Concepts to know
- Buses and interfaces: USB, Thunderbolt, SATA, PCIe, HDMI, DisplayPort; connector and speed differences.
- Storage: capacity, speed, durability; RAID levels and their trade-offs.
- Operating systems: Windows, macOS, Linux, mobile and embedded; 32-bit versus 64-bit; file systems such as NTFS, FAT32, exFAT, ext4, APFS.
- Installation and configuration: partitioning, drivers, updates, licensing, imaging and cloning.
- Virtualisation and cloud: hypervisors, virtual machines, containers.
Traps
Common traps include confusing RAM with storage, assuming more RAM always speeds up a slow disk-bound machine, and muddling 32-bit and 64-bit memory limits. Another trap is thinking a driver is application software. RAID questions often test that RAID 0 has no redundancy, RAID 1 mirrors, and RAID 5 tolerates one disk failure. Also remember that formatting does not securely erase data.
Worked example / rule of thumb
Rule of thumb: diagnose by bottleneck. If a user reports slow boot and slow file copies but low CPU use, suspect storage rather than CPU or RAM, and propose an SSD upgrade. If a machine freezes with many applications open and high memory use, suspect insufficient RAM and check virtual memory settings.
Study tip
Draw a labelled system diagram and annotate each component's function. Explaining why a component matters is more valuable than listing specifications.