Computer Fundamentals and Hardware Concepts
What to know
Every item of data inside a computer is stored as a bit (0 or 1); eight bits form a byte, and byte multiples scale by 1024 in the binary convention (1 KB = 1024 B, 1 MB = 1024 KB, 1 GB = 1024 MB, 1 TB = 1024 GB). The processor (CPU) executes instructions using the arithmetic logic unit, control unit and registers; its throughput depends on clock speed, cores and cache, not on storage size. Memory is a hierarchy: registers, then cache, then RAM (volatile, working memory), then secondary storage such as SSD or HDD (non-volatile). ROM holds firmware such as the boot instructions. Input devices send data in, output devices send results out, and a touchscreen does both. The motherboard carries the buses that connect these parts.
Traps
Questions love to swap bit and byte (a 100 Mbps link delivers about 12.5 MB per second), to claim extra RAM speeds up the CPU, or to treat ROM as rewritable working memory. Watch for "which is volatile" and for units written without the B or b.
Worked example
Convert 2 GB into MB: 2 x 1024 = 2048 MB. If a photo is 4 MB and a drive holds 8 GB, the number of photos is 8 x 1024 / 4 = 2048, not 2000. Rule of thumb: as you move up the memory hierarchy, capacity falls and speed and cost rise.