OCR · GCSE · Computer Science
Course version: J277 · Version from Sept 2022
Primary storage (memory): The purpose of RAM in a computer system
RAM (Random Access Memory) is volatile primary storage that temporarily holds data and instructions currently in use by the CPU.
Checked against the OCR J277 specification on .
- Point 4 of 6
- 3 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
RAM (Random Access Memory) is volatile primary storage that temporarily holds data and instructions currently in use by the CPU. Its purpose is to provide fast, directly accessible working memory so the processor can fetch and execute programs without waiting for slower secondary storage. When a program is opened, its instructions and associated data are copied from secondary storage into RAM. The CPU then reads from and writes to RAM as it processes. RAM is volatile, so its contents are lost when power is removed.
For example: A web browser, its open tabs and the operating system are held in RAM while the computer is running; increasing RAM capacity allows more programs to be held simultaneously, reducing reliance on virtual memory.
What earns the marks
- RAM is volatile, meaning its contents are lost when the power is turned off.
- RAM temporarily stores data and instructions currently being used by the CPU.
- RAM acts as fast primary storage that the CPU can access directly.
- Programs and data are copied from secondary storage into RAM before they can be executed.
- The CPU reads instructions and data from RAM and writes results back to RAM during processing.
- More RAM allows more programs or larger amounts of data to be held in memory at the same time.
Common mistakes and how to put them right
Thinking RAM permanently stores files.
Put it right by stating that RAM is volatile and only holds data temporarily while the computer is on; permanent storage is secondary storage.
Confusing RAM with ROM.
Put it right by explaining that RAM is read/write and volatile, while ROM is read-only during normal use and non-volatile.
Saying RAM stores the operating system permanently.
Put it right by clarifying that the operating system is stored on secondary storage and loaded into RAM when needed.
Exam tips
- Use the phrase volatile working memory and link it to the CPU fetching instructions and data during processing.
- Give a concrete example, such as a game or document being loaded from secondary storage into RAM before it can run.
- When comparing with ROM, mention both volatility and typical purpose to make the distinction clear.
Try the lesson
The start of the Primary storage (memory): The purpose of RAM in a computer system lesson, made from checked teaching notes for this specification point.
Have a go first
What is the main purpose of RAM in a computer system?
Listen
RAM (Random Access Memory) is volatile primary storage that temporarily holds data and instructions currently in use by the CPU. Its purpose is to provide fast, directly accessible working memory so the processor can fetch and execute programs without waiting for slower secondary storage. When a program is opened, its instructions and associated data are copied from secondary storage into RAM. The CPU then reads from and writes to RAM as it processes. RAM is volatile, so its contents are lost when power is removed. For example, a web browser, its open tabs and the operating system are held in RAM while the computer is running; increasing RAM capacity allows more programs to be held simultaneously, reducing reliance on virtual memory. A strong answer earns marks for these points. RAM is volatile, meaning its contents are lost when the power is turned off. RAM temporarily stores data and instructions currently being used by the CPU. RAM acts as fast primary storage that the CPU can access directly. Programs and data are copied from secondary storage into RAM before they can be executed. A common slip: Thinking RAM permanently stores files. Instead, stating that RAM is volatile and only holds data temporarily while the computer is on; permanent storage is secondary storage. Exam tip: Use the phrase volatile working memory and link it to the CPU fetching instructions and data during processing.
Key words
Say what each word means before you turn the card.
Primary storage
Try answering aloud or in your head before turning the card.
Volatile memory
Try answering aloud or in your head before turning the card.
CPU working memory
Try answering aloud or in your head before turning the card.
See every definition
- Primary storage
- Fast storage that the CPU can access directly, with RAM acting as this type of storage.
- Volatile memory
- Memory whose contents are lost when the power is removed, as is the case with RAM.
- CPU working memory
- Fast, directly accessible memory that temporarily holds data and instructions currently in use by the CPU.
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