Memory concepts in Linux OS

[KUPI]

Hello Everyone,

These concepts are little confusing..
Most of them looks same. But actually they are not.

Can someone explain me to understand these concepts. Every time i am getting confused.

Virtual memory,
Swap memory,
Paging,
Heap memory,
Cache,
Buffer.

Thanks in advance.

 

[kc1di]

Hello @KUPI,
these pages may help your understanding.

Understanding memory information on Linux systems - Linux Audit

Linux memory management is an extensive subject. This guide helps you understanding the how to analyze it and obtain availabile memory information.

linux-audit.com

Concepts overview — The Linux Kernel documentation

 

[Brickwizard]

this may not be the technical answer but its the way I see it

Virtual memory,
Swap memory,

not usually a part of Linux, these are Windows add hock applications to cover a short fall in system resources [insufficient built in ram], Linux has the option of installing a swap partition [ this is often discussed across the net, as to if it is necessary
with modern kit] if you do opt for a swap partition, it should be at least the same size as the ram installed.

Paging,

this is the way Linux Kernel handles blocks of data

Heap memory,

again is part of the Kernal, and is the way the Kernel makes temporary memory available when needed and is a fluid memory, constantly changing in volume subject to demand

Cache,

this is most often associated with applications such as browsers, where cache pages are held in memory to speed up loading when called for

Buffer.

can be either a built-in memory on a component [GPU, CPU, sound card etc] or allocated by the kernel, it is a short term memory used to level out the transmission of information between components, applications and your machine. to make it run smoother.

so there you go my non techno interpretation

 

[osprey]

Brickwizard wrote:

this may not be the technical answer but its the way I see it

Virtual memory,
Swap memory,

not usually a part of Linux, these are Windows

I'm not sure I follow that text in post #3. Virtual memory is a central part of the linux kernel:

Concepts overview — The Linux Kernel documentation

Swap memory is described here:

Swap Management

There shouldn't be any confusion between "swap" and "virtual memory". The latter is a fundamental mechanism of the kernel, the former, optional.

The terms in linux kernel matters often have particular meanings with nuances that differentiate them from the meaning of the terms in ordinary speech. For example:

Strictly speaking, Linux does not swap as “swapping” refers to coping [sic] an entire process address space to disk and “paging” to copying out individual pages. Linux actually implements paging as modern hardware supports it, but traditionally has called it swapping in discussions and documentation. To be consistent with the Linux usage of the word, we too will refer to it as swapping.

From: https://www.kernel.org/doc/gorman/html/understand/understand014.html

 

[KUPI]

Hello @KUPI,
these pages may help your understanding.

Thank you.

 

[KUPI]

this may not be the technical answer but its the way I see it

not usually a part of Linux, these are Windows add hock applications to cover a short fall in system resources [insufficient built in ram], Linux has the option of installing a swap partition [ this is often discussed across the net, as to if it is necessary
with modern kit] if you do opt for a swap partition, it should be at least the same size as the ram installed.

this is the way Linux Kernel handles blocks of data


again is part of the Kernal, and is the way the Kernel makes temporary memory available when needed and is a fluid memory, constantly changing in volume subject to demand

this is most often associated with applications such as browsers, where cache pages are held in memory to speed up loading when called for

can be either a built-in memory on a component [GPU, CPU, sound card etc] or allocated by the kernel, it is a short term memory used to level out the transmission of information between components, applications and your machine. to make it run smoother.

so there you go my non techno interpretation

Thanks for the details.

 

[KUPI]

Brickwizard wrote:


I'm not sure I follow that text in post #3. Virtual memory is a central part of the linux kernel:

Concepts overview — The Linux Kernel documentation

Swap memory is described here:

Swap Management

There shouldn't be any confusion between "swap" and "virtual memory". The latter is a fundamental mechanism of the kernel, the former, optional.

The terms in linux kernel matters often have particular meanings with nuances that differentiate them from the meaning of the terms in ordinary speech. For example:

From: https://www.kernel.org/doc/gorman/html/understand/understand014.html

Thank you