---
title: "Memory and Storage: RAM, ROM and the Backing Store"
description: "Where a machine keeps things: fast memory that empties at power off for what is running now, permanent storage for what has to survive. Speed, size and cost pull against each other."
canonical: https://lightmysky.com/learn/computing/memory-and-storage-ram-rom-and-the-backing-store-mt_AiXGJioO_S
source: https://lightmysky.com/learn/computing/memory-and-storage-ram-rom-and-the-backing-store-mt_AiXGJioO_S.md
retrieved: 2026-09-12
---

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# Memory and Storage: RAM, ROM and the Backing Store

Where a machine keeps things: fast memory that empties at power off for what is running now, permanent storage for what has to survive. Speed, size and cost pull against each other.

Subject: Computing · Area: Computer Systems · Ages 15 to 16
Page: https://lightmysky.com/learn/computing/memory-and-storage-ram-rom-and-the-backing-store-mt_AiXGJioO_S

## Ready when they can

- Say what is lost when the power goes and what is not
- Explain why a program is copied from storage into memory before it runs
- Compare storage kinds on speed, capacity and durability for a stated use

## Lesson: Fast now, safe forever

Memory holds what runs right now and forgets at power off. Storage keeps files safe for weeks with no power at all. That split is why unsaved work dies with a dead laptop.

**Example.** A restart that cures a slow machine proves the point: it sweeps piled-up programs out of RAM and frees fast space. Nothing stored is touched, since storage never needed power to remember.

Nothing runs straight from storage. The processor copies the program into memory first, then works there. Games save progress to files for the same reason: memory only lasts while the program runs.

**Tip.** Shop the trade-off with open eyes. HDDs give more room per coin, while SSDs read and write faster with no moving parts. Whatever you pick, back up to a separate drive twice the size.

**Recap.** Memory serves the running moment and storage guards the future, so save often and back up apart.

## Practice

8 questions on this page, each with its working shown.

## Needs first

- [Where a File Lives: Folders, Names and Backups](https://lightmysky.com/learn/computing/where-a-file-lives-folders-names-and-backups-mt_UvLO9CA3BY)
- [Inside the CPU: Fetch, Decode, Execute](https://lightmysky.com/learn/computing/inside-the-cpu-fetch-decode-execute-mt_YT-FSWnUKR)

## Opens up

- [The Memory Hierarchy and Why Caching Works](https://lightmysky.com/learn/computing/the-memory-hierarchy-and-why-caching-works-mt_0f5ArFPlxP)
- [Packets and Protocols on a Network](https://lightmysky.com/learn/computing/packets-and-protocols-on-a-network-mt_IffXVDtfLX)
- [Registers, Buses and the Fetch-Execute Cycle in Detail](https://lightmysky.com/learn/computing/registers-buses-and-the-fetch-execute-cycle-in-detail-mt_yjy3eSStzH)