512MB RAM???

[QkiZ]

In white paper of Xperia J is written that smartphone have 512MB of RAM. But when I run shell command 'free'  via ADB i get 380MB. I found other topics about this issue but they do not explain the memory usage. Regardless of how much memory is used up, the 'free' command should show the list of whole, free and consumed memory. For example:

root@android:/ # free
             total         used         free       shared      buffers
Mem:        389780       382172         7608            0        10672
-/+ buffers:             371500        18280
Swap:            0            0            0

If the Xperia J had to actually 512MB command 'free' should show:

root@android:/ # free
             total         used         free       shared      buffers
Mem:        524288       382172         142116            0        10672
-/+ buffers:             371500        18280
Swap:            0            0            0

 Maybe the memory is somehow locked to, for future use in case of an update.

[Rickard]

The phone has 512MB RAM but not all of that is available for apps and Android. Some memory is for example used for the graphics and some for the kernel. The command free will not show you the total amount of RAM the phone has.

[QkiZ]

I'm not asking about the memory available for applications. If the remaining memory (132MB) would be visible to the kernel, it can be see in /proc/meminfo summary. But it is not.

Unless it is a 132MB graphics memory, that I'll understand.

[Rickard]

I don't know how much RAM that is reserved for the graphics alone but from what i've been able to find there are also other parts that uses memory that you can't see like the kernel and other hardware parts. 

[QkiZ]

If kernel use that "hidden" memory I could be able to see it via standard linux commands. I have rooted Xperia J. What other hardware can use that memory?

[Rickard · Accepted solution]

I don't have details about what hardware that has RAM reserved but i do know that some is reserved for GPU and in some models also for the camera.

If you want more detailed information about the use of memory i think you need to use the developer channels (http://developer.sonymobile.com/about/how-do-i-get-in-contact/).

[QkiZ]

Thanks for informator 🙂

[QkiZ]

*information