Computer Fundamentals and Hardware
Core concepts
A candidate must be fluent in number systems and data representation (binary, octal, hexadecimal, two's complement, BCD, ASCII vs Unicode), the stored-program (von Neumann) model, and the fetch-decode-execute cycle. Know the CPU's parts - ALU, control unit, registers (PC, IR, MAR, MBR, accumulator), cache levels - and how clock speed, word length, and bus width affect performance. Storage hierarchy (registers → cache → RAM → SSD/HDD → optical → tape) and the volatility/speed/cost trade-offs are frequently tested. Input/output devices, ports, and memory types (SRAM vs DRAM, ROM variants, flash) round out the fundamentals.
Traps to watch
Questions love mixing units: 1 KB is 1024 bytes in binary convention, but storage vendors use 1000. Two's complement range for n bits is −2^(n−1) to 2^(n−1)−1, not symmetric. Distinguish RISC (few simple instructions, more registers, pipelining) from CISC. Do not confuse cache with virtual memory; do not call ROM "read-only" when flash is rewritable. Latency vs throughput and clock speed vs actual performance (IPC) are classic distractors.
Worked example / rule of thumb
To convert decimal 45 to binary, repeatedly divide by 2 and read remainders bottom-up: 45→22 r1, 22→11 r0, 11→5 r1, 5→2 r1, 2→1 r0, 1→0 r1, giving 101101. Quick check: 32+8+4+1=45. Rule of thumb: when a question mentions "fastest memory," answer registers, then cache, then RAM - never hard disk.