This key facts covers How Virtual Memory Works within Virtual Memory for GCSE Computer Science. Revise Virtual Memory in Memory & Storage for GCSE Computer Science with 15 exam-style questions and 16 flashcards. This topic appears less often, but it can still be a useful differentiator on mixed-topic papers. It is section 3 of 9 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 3 of 9
Practice
15 questions
Recall
16 flashcards
How Virtual Memory Works
The Process:
- Memory fills up: You open too many programs - Chrome with 20 tabs, Word, Excel, Spotify, Photoshop. Physical RAM (8GB) is now full.
- OS intervenes: Operating system identifies less-used data in RAM (e.g., a background program you haven't touched in 10 minutes).
- Paging out: OS copies this data from RAM to the page file on the hard drive, freeing up RAM space.
- New program loads: The freed RAM is now available for the new program you want to run.
- Paging in: When you switch back to that background program, OS swaps it back from hard drive to RAM (paging in) and may page out something else.
Key Terms:
- Page file / Swap space: Reserved area on hard drive used as virtual memory extension
- Paging: The process of swapping data between RAM and hard drive
- Page: A fixed-size block of data (typically 4KB) that gets moved
- Page fault: When a program tries to access data that's been paged out - OS must page it back in
- Thrashing: When the system spends more time paging than executing programs (severe slowdown)