Information Technology Fundamentals and Computer Systems
This domain tests whether you can explain what a computer is made of, how it stores and processes data, and how an operating system manages the machine. Expect questions on hardware versus software, the memory hierarchy, storage units, number systems and basic OS functions.
Core rules
- A computer follows the IPO(S) cycle: input → processing → output, with storage.
- Hardware is physical; software is the set of instructions. System software (OS, device drivers, utilities) runs the machine; application software does user tasks.
- The CPU has an Arithmetic Logic Unit (ALU), a Control Unit (CU) and registers. Clock speed in GHz is only one factor in performance.
- Primary memory: RAM (volatile, working area), ROM (non-volatile, firmware), cache (fastest, smallest). Secondary storage: HDD, SSD, pen drive, DVD - non-volatile and cheaper per GB.
- 1 byte = 8 bits; 1 KB = 1024 bytes; then MB, GB, TB, PB.
- An OS manages processes, memory, files and devices, and provides the user interface.
Worked example
Convert binary 1011 0110 to decimal and hexadecimal. Place values left to right: 128, 64, 32, 16, 8, 4, 2, 1. Set bits: 128 + 32 + 16 + 4 + 2 = 182. For hex, split into nibbles: 1011 = 11 = B, 0110 = 6, so the answer is B6 in base 16. Reasoning: binary-to-hex is quick because each hex digit is exactly four bits.
Traps that cost marks
- Writing 1 KB = 1000 bytes; in this syllabus it is 1024.
- Mixing Mbps (megabits per second, network speed) with MB (megabytes of storage); divide by 8.
- Calling an SSD 'memory' - it is secondary storage.
- Saying ROM is volatile, or that a GUI is an operating system.
- Confusing the ALU (does arithmetic and logic) with the CU (directs operations).