# Resident and Virtual memory on Linux: A short example

DevFeed: [Resident and Virtual memory on Linux: A short example](<https://devfeed.tech/articles/resident-and-virtual-memory-on-linux-a-short-example-35454.md>)

Original publisher: [Read original article](<https://darkcoding.net/software/resident-and-virtual-memory-on-linux-a-short-example/>)

Author: Graham King

Published: 2012-10-03T05:29:42Z

Content type: tutorial

Language: en

Sources: [Graham King](<https://devfeed.tech/sources/graham-king.md>)

Topics: [Linux](<https://devfeed.tech/topics/linux.md>), [Processes](<https://devfeed.tech/topics/processes.md>), [Kernel](<https://devfeed.tech/topics/kernel.md>), [C](<https://devfeed.tech/topics/c.md>)

Tags: [c](<https://devfeed.tech/tags/c.md>), [kernel](<https://devfeed.tech/tags/kernel.md>), [linux](<https://devfeed.tech/tags/linux.md>), [memory](<https://devfeed.tech/tags/memory.md>), [memory-management](<https://devfeed.tech/tags/memory-management.md>), [processes](<https://devfeed.tech/tags/processes.md>), [software](<https://devfeed.tech/tags/software.md>), [unix](<https://devfeed.tech/tags/unix.md>)

## AI overview

This tutorial explains the difference between resident memory (RES), which represents physical RAM used by a process, and virtual memory (VIRT), which represents the memory the process believes it has available. A short C program demonstrates that requesting memory does not allocate physical memory until the program uses it, so virtual memory can greatly exceed resident memory.

## Source excerpt

Demystifying memory: RES is real, VIRT is virtual.