1.5 Primary Storage (Memory)
Primary Storage is internal storage that can be directly accessed by the CPU - so access speeds are very quick.
Storage is split into two types - volatile and non-volatile.
Volatile memory is temporary (data is lost whenever the power is turned off).
Non-volatile memory saves the data even when not being powered, so it can be accessed when the computer is next on and can be stored long-term.
There are four main types of memory:
Read Only Memory (ROM)
Random Access Memory (RAM)
What is RAM?
What is ROM?
ROM is non-volatile storage that cannot be changed - which is why it is called 'read-only'.
ROM stores the start-up instructions for when the computer is switched on. It is vital that these instructions are stored in ROM so they cannot be accidentally changed or the computer won't start up properly.
RAM is volatile (temporary) storage that stores all programs that are currently running as well as the operating system.
RAM is made up of storage locations that are identified with a unique address. RAM holds instructions that are fetched as part of the FDE cycle.
What is stored in RAM?
Currently Running Programs & the Operating System
What is stored in ROM?
What is Cache Memory?
What is Flash?
What is stored in Cache?
Flash memory is used to permanently store data as it is non-volatile and not deleted when power is lost.
Flash memory can be edited and is used in portable devices like USB sticks and camera memory cards.
Cache memory is volatile (temporary) storage that stores data that is frequently accessed. It is very quick to access because it is closer to the CPU than other types of memory like RAM.
Frequently Accessed Data
What is stored in Flash?
Images, Videos, Files
a. What is the difference between volatile and non-volatile storage?
a. What is the difference between primary and secondary storage?
b. For each of the four types of primary memory, describe its role and give an example of what it can store.