System Memory Hierarchy

Revision Module: Volatile vs Non-Volatile Storage

01 // PRIMARY STORAGE

Primary memory is directly accessible by the CPU. It is categorized by its ability to retain data without power.

Type Full Name Volatility Function
RAM Random Access Memory Volatile (Lost on power-off) Holds open applications and the OS while the computer is running.
ROM Read Only Memory Non-Volatile (Permanent) Contains the BIOS/UEFI bootstrap instructions to start the computer.
02 // VIRTUAL MEMORY

Conceptual Mechanics

When RAM is full, the OS uses a portion of the hard drive as Virtual Memory. This prevents system crashes but significantly slows performance because the HDD/SSD is slower than physical RAM.

[ DIAGRAM: RAM overflow mapping to Secondary Storage ]
03 // SECONDARY STORAGE

Required for long-term storage of files. Categorized by physical medium:

Magnetic
Uses magnetised dots. High capacity, low cost.
Ex: HDD, Magnetic Tape.
Optical
Uses lasers to read pits/lands. Durable, portable.
Ex: CD, DVD, Blu-Ray.
Solid State
Uses flash memory (no moving parts). Extremely fast.
Ex: SSD, USB Flash Drive.
04 // KNOWLEDGE DIAGNOSTICS

Select the correct response for each system prompt to verify data retention.

PROMPT 01: Which type of memory is used to store the bootstrap instructions (BIOS/UEFI)?



PROMPT 02: What happens to data in Volatile memory when the power is cut?



PROMPT 03: Virtual Memory is a simulated extension of which component?