Computer Fundamentals and Hardware
What the exam tests
This domain supplies a large block of one-mark questions: the block diagram of a computer, generations, the memory hierarchy, number systems and logic gates. Definitions are marked strictly, and small conversions must be worked by hand without a calculator.
Core concepts
- Von Neumann block diagram: input unit → CPU (control unit, arithmetic logic unit, registers) → memory unit → output unit, joined by the system bus (address, data, control).
- Memory hierarchy: registers (fastest, inside the CPU) → cache → RAM → secondary storage. RAM is volatile working memory; ROM is non-volatile and holds firmware such as the BIOS. HDD, SSD, optical disc and pen drive are non-volatile, cheaper per byte and slower.
- Units: 1 byte = 8 bits; 1 KB = 1024 bytes = 2^10; 1 MB = 1024 KB; 1 GB = 1024 MB; 1 TB = 1024 GB.
- Ports and buses: USB, HDMI, VGA, RJ-45 Ethernet, audio jacks. A bus is a group of parallel conductors carrying signals.
Worked example
Convert decimal 45 to binary. Divide repeatedly by 2, recording remainders: 45÷2 = 22 remainder 1; 22÷2 = 11 remainder 0; 11÷2 = 5 remainder 1; 5÷2 = 2 remainder 1; 2÷2 = 1 remainder 0; 1÷2 = 0 remainder 1. Read the remainders from bottom to top: 101101. Check with place values: 32 + 8 + 4 + 1 = 45. Six bits fit in one byte, padded with two leading zeros.
Traps
- Calling ROM strictly 'read only' is only partly right: flash ROM can be rewritten, yet it stays non-volatile.
- In this syllabus 1 KB is 1024 bytes, not 1000.
- A bit is a binary digit; a byte is 8 bits - never interchange the two in an answer.
- Cache is faster than RAM, and RAM is faster than SSD; reverse order loses the mark.