⏱ 4 min read
Computer Operator Paper II and job-knowledge MCQs regularly ask about the CPU, memory, storage, the motherboard, booting and basic troubleshooting. This note collects those points in one place.
1. Main hardware parts
| Part | Role |
|---|---|
| CPU (processor) | The “brain”: ALU does arithmetic and logic, CU controls operations, registers hold data being processed. |
| Motherboard | Main circuit board connecting CPU, RAM, storage and expansion cards. |
| SMPS | Switch Mode Power Supply: converts AC mains to low-voltage DC for parts. |
| RAM | Main working memory; volatile. |
| Hard disk / SSD | Permanent storage of files and the operating system. |
| GPU / graphics card | Processes images and video for the display. |
| NIC | Network Interface Card for LAN connection. |
2. Memory
- Primary memory: RAM and ROM, directly accessed by the CPU.
- RAM is volatile (data lost when power is off). Types: SRAM (faster, used for cache) and DRAM (cheaper, used as main memory).
- ROM is non-volatile. Types: PROM, EPROM (erased with UV light), EEPROM (erased electrically; flash memory is a type of EEPROM).
- Cache memory sits between CPU and RAM to speed up access.
- Registers are the fastest memory, inside the CPU.
- Virtual memory uses part of the hard disk as extra RAM.
- Speed order: Registers > Cache > RAM > SSD > Hard disk.
3. Memory units
| Unit | Size |
|---|---|
| Bit | 0 or 1 |
| Nibble | 4 bits |
| Byte | 8 bits |
| Kilobyte (KB) | 1024 bytes |
| Megabyte (MB) | 1024 KB |
| Gigabyte (GB) | 1024 MB |
| Terabyte (TB) | 1024 GB |
| Petabyte (PB) | 1024 TB |
4. Storage devices
- Magnetic: hard disk, floppy disk, magnetic tape (sequential access, used for backup).
- Optical: CD (about 700 MB), DVD (4.7 GB single layer), Blu-ray (25 GB single layer).
- Flash / solid state: pen drive, SSD, memory card; no moving parts.
- Hard disk speed is measured in RPM (e.g. 5400, 7200).
5. Booting and BIOS
- Booting is the process of starting a computer and loading the operating system.
- Cold boot: starting from power off; warm boot: restarting (e.g. Ctrl+Alt+Del or Restart).
- BIOS (Basic Input Output System) is stored in ROM/flash on the motherboard; newer systems use UEFI.
- POST (Power-On Self Test) checks hardware at startup; beep codes signal errors.
- CMOS stores BIOS settings and the clock; a small CMOS battery keeps it powered.
6. Basic troubleshooting
| Problem | Likely cause / first check |
|---|---|
| No power, no lights | Power cable, socket, UPS or SMPS |
| Beeps and no display | RAM not seated properly or faulty; reseat RAM |
| Wrong date and time every start | Weak CMOS battery |
| Very slow computer | Too many startup programs, low RAM, full disk or malware |
| “Operating system not found” | Boot order wrong or hard disk failure |
| No internet | Cable, Wi-Fi, router, IP settings; try ping |
| Printer not printing | Power, cable, driver, paper jam, print queue |
| Blue screen (BSOD) | Driver or hardware error in Windows |
- Use Task Manager (Ctrl+Shift+Esc) to end non-responding programs.
- Disk Cleanup removes temporary files; defragmentation rearranges file pieces on a hard disk (not needed for SSD).
- Keep antivirus and system updates current; take regular backups.
- A UPS gives backup power and protects against sudden power cuts.
7. Types of computers by size
| Type | Feature | Use |
|---|---|---|
| Supercomputer | Fastest and most powerful | Weather forecasting, research |
| Mainframe | Serves many users at once | Banks, large organisations |
| Minicomputer | Medium size | Small businesses |
| Microcomputer | Personal use | Desktops, laptops |
8. Storage devices compared
- Hard disk (HDD): large and cheap, but slower and has moving parts.
- Solid state drive (SSD): faster, with no moving parts.
- Pen drive: small and portable flash storage.
- Optical discs (CD, DVD): read by a laser.
9. How this topic is asked in the exam
Objective questions ask the types of computers, the difference between HDD and SSD and examples of storage devices.
📌 Key points to remember
- CPU = ALU + CU + registers; motherboard connects everything.
- RAM volatile, ROM non-volatile; SRAM for cache, DRAM for main memory.
- Fastest memory: registers, then cache.
- 1 byte = 8 bits; 1 KB = 1024 bytes; nibble = 4 bits.
- BIOS runs POST at startup; CMOS battery keeps date and settings.
- Cold boot from power off; warm boot = restart.
- Beeps with no display often mean a RAM problem; wrong time means a weak CMOS battery.
📝 Quiz
Test yourself: Computer Hardware, Memory and Troubleshooting for Computer Operator
Practise Main hardware parts, Storage devices and Basic troubleshooting with 50 questions. Each attempt picks 25 at random.
Loading quiz...