05-13-2011 10:51 AM
- I should know this by now but I thought I'd ask....
Can someone explain how smartphone memory works? I know there is ROM, RAM, and the SD card; but ... please were applications are stored and how the performance of a smartphone depends on the memory capacity.
Please correct me if I am wrong is how I think memory in a smartphone works:
In ROM, the OS and applications are stored.
In RAM, when the smartphone has booted up, the OS and applications that are started are stored there.
On the SD card, applications and other files can be stored.
Here is another question: Which Android smartphones has the more internal memory?
Thanks in advance for all replies.
gabato05-12-2011 10:16 PM
- 05-13-2011 08:58 AM
- Every phone is different, and as mentioned, you would need to read the specs on the phone to get the details. But, In general, the way Android refers to its memory is:
- Internal Flash memory
- SD Card
Just like on any other computer, RAM is where apps are executed and where any data an app is using at the moment is stored. (Or said simply: when you open an app, it's read from storage into RAM and then executed.) RAM is not permanent and is routinely cleaned up by the OS as programs are closed. Every OS, be it Windows, OS-X, or Android, handles the details in vastly different ways, but in general this is how it works.
This is why the general rule-of-thumb is "The more RAM you have, the more apps you can run simultaneously". The keyword is "run". The amount of RAM has no bearing on how many apps you can install. You can install 100's of gigabytes of apps if you want; you just probably won't be able to run them all at the same time!
Internal Storage (aka Internal Memory)
The internal storage is flash memory, just like your SD Card. Only it's built-in and can't be changed. In general terms, Android divides the internal memory into two partitions:
- One partition will be marked as read-only by the system. This "read-only" partition is where the Android OS actually lives. Programs and users can't modify this without "rooting" the phone. (This read-only system partition is also referred to as ROM, but this is actually a misnomer as the memory is technically R/W.)
-- The other partition of the internal memory is used to store the apps you install plus their data. This partition is also locked down, but not quite as heavily as the system partition. Each app can modify its own files, but in general, can't access or see other apps. The user doesn't have direct access here, either, without rooting their phone. (Which is why backup programs usually require ROOT access in order to backup the app and all of its data)
So remember, even if the phone's specs say "2GB of internal memory" some or half of that will be unusable by the user.
This is the little SD memory card you install in the phone. It's marked as "public" storage by the system. Meaning anyone, be it an app or the user, can write, read, delete, and modify any of the files on this card. On stock Android, apps can also be installed here, but only if the developer enables this. The SD Card is used by the user to store anything they want. In general, all your photos, music, and movies will be stored here.
[SECURITY NOTE: An app has to declare that it will use the SD Card. For security, this declaration will be displayed and you have to accept it before you can even install the app.]05-13-2011 10:51 AM
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