General Knowledge
Computer Memory
Learn the memory hierarchy, units, primary/secondary storage and common exam comparisons.
Study progress
1. Memory Hierarchy
Registers and cache are very fast and close to the CPU; RAM is primary working memory; secondary storage is larger and persistent.
2. RAM and ROM
RAM is generally volatile working memory. ROM is non-volatile memory used for firmware or persistent instructions.
3. Cache
Cache stores frequently used data/instructions to reduce CPU access time.
4. Units
Bit is the smallest binary unit; 8 bits = 1 byte. Larger units include KB, MB, GB, TB.
5. Secondary Storage
HDD, SSD, optical media and other persistent storage retain information after power is removed.
Memory Tricks & Quick Recall
Speed ladder: Register → Cache → RAM → Secondary. Memory trick: “Nearer to CPU = faster; farther away = larger and slower.”