Describe the types of ROM (Mask ROM, PROM, EPROM, EEPROM, Flash).
Explain the difference between volatile and non-volatile memory.
Primary Memory: Two Families
Primary memory is the working memory the CPU can access directly.
⚡ RAM
Volatile: loses its contents when power is off.
Read and write. Holds the programs and data in use right now.
🔒 ROM
Non-volatile: keeps its contents without power.
Mostly read. Holds firmware and start-up instructions.
Volatile vs Non-Volatile: Sort It!
Click each memory type to assign it to the correct category.
VOLATILE
NON-VOLATILE
RAM: Characteristics
Volatile: data is lost when the power is turned off
Read-write: data can be read and changed
Random access: any location can be reached directly
Fast and temporary: used for active programs and data
More RAM lets you run more programs at once and work with larger files.
Two Kinds of RAM: SRAM and DRAM
Static RAM (SRAM)
Uses flip-flop circuits (6 transistors per bit). No refresh needed.
Very fast, expensive, low density.
Used for CPU cache.
Dynamic RAM (DRAM)
Uses 1 transistor and 1 capacitor per bit. The capacitor leaks, so it is refreshed thousands of times per second.
Cheaper, denser, slower than SRAM.
Used for main memory.
SRAM vs DRAM: Which is Which?
Click a property card. Select SRAM or DRAM, then reveal the answer.
Score: 0 / 0
DDR SDRAM Generations
Modern DRAM transfers data twice per clock cycle (Double Data Rate).
Generation
Transfer rate
Voltage
Year
DDR
200–400 MT/s
2.5 V
2000
DDR2
400–800 MT/s
1.8 V
2003
DDR3
800–1600 MT/s
1.5 V
2007
DDR4
1600–3200 MT/s
1.2 V
2014
DDR5
3200–6400+ MT/s
1.1 V
2020
Each generation is faster, uses less power, and holds more per module.
ROM: Characteristics and Types
ROM keeps its data without power and stores permanent start-up instructions.
Type
How it is written or erased
Typical use
Mask ROM
Written at the factory; cannot change
Mass-produced devices
PROM
Programmed once by burning fuses
Custom firmware
EPROM
Erased with UV light through a quartz window
Development and prototyping
EEPROM
Erased electrically, byte by byte
BIOS chips, settings
Flash
Erased electrically in blocks
SSDs, USB drives, phones
ROM Types: Name That Memory!
Read the description, then click the matching ROM type to reveal if you are correct.
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RAM vs ROM
Feature
RAM
ROM
Volatility
Volatile
Non-volatile
Operation
Read and write
Mostly read
Speed
Faster
Slower
Capacity
Larger
Smaller
Purpose
Active programs and data
Firmware and boot code
Without power
Data lost
Data kept
RAM vs ROM: Attribute Challenge
Each row shows an attribute. Click the correct winner — RAM or ROM.
Attribute
RAM
ROM
Score: 0 / 0
Memory in a Modern Computer
BIOS/UEFI: boot firmware in Flash ROM
CPU cache (L1, L2, L3): SRAM
System RAM: DDR4 or DDR5 DRAM
Storage: SSDs built on Flash memory
Boot sequence: power on → BIOS/UEFI runs from ROM → POST checks the hardware → bootloader and operating system load into RAM → applications run from RAM.
Boot Process: Order the Memory Steps!
Click the steps in the correct order from power-on to OS ready.
Your sequence (click to add):
Buying Tip: How Much RAM?
8 GB is a sensible minimum for office work and study.
16 GB is better for heavy multitasking, design, or programming.
Check whether RAM is soldered (no upgrades later) or in a slot.
Check the type: DDR4 and DDR5 modules are not interchangeable.
Key Takeaways
RAM is volatile and holds active work; ROM is non-volatile and holds firmware.
SRAM is faster and more expensive than DRAM, so it is used for cache.
Each DDR generation improves speed and efficiency.
Flash memory, a type of EEPROM, is the basis of SSDs and USB drives.
Different memory types work together in a hierarchy.
Exam Practice: Short Answer
Differentiate between RAM and ROM.
Differentiate between SRAM and DRAM.
What is flash memory? Where is it used?
Exam Practice: Long Answer
Explain the types of RAM and ROM.
Describe the role of RAM and ROM in the boot process of a computer.
Revise the chapter note before writing these answers.