Primary Storage (Memory): Computer Science OCR: GCSE (9:1)

Secondary

This type of storage cannot be read directly by the CPU. It's non-volatile and much bigger than primary. Examples are Hard Disk, USB Flash Drive, SSD, CD

Primary

This type of storage is also known as main memory or primary memory. It is volatile and can be accessed directly by the CPU

Random Access Memory

Primary Storage we can write to, also known as main memory. All data in use and instructions currently running are stored here. It is volatile.

Read Only Memory

Cannot be changed. Non-volatile semiconductor primary memory, contains the start-up instructions for the computer known as the BIOS

Volatile

Forgets all contents when powered off, RAM is this type

Non-volatile

Remembers all contents when powered off, ROM is this type

Write

We can do this to RAM but not ROM, it means change the contents

BIOS

The startup instructions for a computer, stored in ROM. It stands for Basic Input Output System

Virtual memory

Space in secondary storage that acts like extra RAM, so we can run more processes simultaneously

Process

Any part of a program that is currently running, this will need to be in primary memory so the CPU can execute it

Swapping

Moving a process from RAM to virtual memory to make more room in RAM for a new process

Thrashing

Constantly swapping processes between RAM and virtual memory because there is not enough RAM. Causes slow performance.

Running

Currently executing. (A process must be loaded in RAM before it can be executed)