Memory Types Flashcards
What are the 2 types of memory?
Main Memory
Secondary Storage
What is Main Memory?
Is any memory that is directly accessed by the CPU
Give 2 example of Main Memory
Random Access Memory (RAM)
ROM chips
What is Secondary Storage used for?
Is used for holding large amounts of data and programs long-term, but can only be accessed relatively slowly
Give 2 examples of Secondary Storage
Hard Disks
Flash Memory
What happens to Volatile Memory when power is switched off?
It is cleared whenever the supply of power is lost
What happens to Non-Volatile Memory when power is switched off?
It will continue to hold anything it was storing even if it is not receiving any power
Is Main Memory Volatile or Non-Volatile?
Volatile (Except ROM chips)
Is Secondary Storage Volatile or Non-Volatile?
Non-Volatile, as the programs and data that are held there are meant to be kept long-term
Give some examples of Volatile Memory
RAM
Cache
CPU Registers
What does RAM store?
Temporarily stores program instructions and data
What 2 types of RAM are there?
DRAM (Dynamic Random Access Memory)
SRAM (Static Random Access Memory)
Why is DRAM often used for Main Memory?
Because it’s relatively inexpensive
Why is SRAM often used for cache?
Because it is much faster to access than DRAM
State 5 things about DRAM
Volatile Memory Used in RAM modules Less expensive than SRAM Slower to access than SRAM Requires a refresh signal to retain its data intact
State 5 things about SRAM
Volatile Memory Used in the cache More expensive than DRAM Faster to access than DRAM No refresh signal needed
Why does DRAM continuously need a ‘refresh signal’?
To keep its capacitors charged, otherwise it will lose the data it is holding
How many bytes are in 1KB
1024
What does ROM stand for?
Read Only Memory
Why is ROM a type of Main Memory?
Because it is directly accessed by the CPU
What is a key difference between ROM and RAM?
ROM is Read Only which means that it cannot be changed, overwritten or removed, whereas RAM is read/write memory which means that the contents can be altered
Is ROM Volatile or Non-Volatile?
Non-Volatile
What is ROM used to store?
Basic computer hardware settings
Is Virtual Memory Volatile or Non-Volatile?
Volatile
What is Disk Thrashing?
Is a problem that may occur when virtual memory is being used. As main memory fills up, then more and more pages need to be swapped in and out of virtual memory. This swapping leads to a very high rate of hard disk access leading to wear and tear on the disk and a slow-down in overall performance
