The way Android describes its file system is an absolute dog's breakfast and is thoroughly confusing.

There is, as you rightly say, the phone's core storage area sometimes called "Phone Internal Storage". This is where the operating system and configuration files live. In normal usage, you won't directly have anything to do with this.

Then there is what is sometimes referred to as the "SD Card". This is where it starts to get stupid. This isn't the removable SD card you may have in your phone (I have a 64GB one in mine). This is really just more internal storage built into the phone. This is called "SD Card" for historical reasons. This is the default storage location for almost everything apart from the OS. All your apps and their data, your music, your photos etc. will all be stored there by default.

Finally, there is the "External SD Card". This is the removable one. What you store here is largely up to you. You have to change configuration settings in various apps to tell them to store data on the removable SD card but this is worth doing if you know how because it frees up a lot of space on the internal "SD Card" memory, which isn't very big on the S4.

 

PS Don't get me started on the actual file system path names (which you won't normally need to know) - these are even more of a bugger's muddle than the nomenclature I was talking about above.

 

lotus49, I think I have just read the most accurate, susinct and eloquent description of the dogs breakfast that is Android's file system.

 

A) you can use the built in file manager. For hidden folders and files you'll need to be rooted and use a third party file manager (I recommend Root Explorer).

B)Yes, they can be cut, moved, copied and pasted.

C) Somewhere deep in a folder I would imagine. I don't actually know, but you would need a third party file manager to find them.

D) You can't, that is down to the developer of the app in question to give you the option. Folders and files created by an app can be copied/pasted to anywhere, but the app that created them will not be able to see them or wrote to a new folder you create yourself if they are in a different location.

 

Some apps allow you to specify where some of their data are stored, but otherwise you cannot change it.

Call log, sms are stored in /data/data/com.android.providers.telephony/databases. You'll need root to see the contents of that folder, and they are stored in sql database files, and cannot be moved.

Yes, downloaded apps are stored in internal memory. I believe Samsung added the ability to move apps to SD back to the S4 after being caught out by mainstream media misleading people about this, but don't have one to confirm. It only moves part of the app anyway.

 

I'm not in a position to check this myself but if you have tried a file manager and it said permission denied to access that folder, I don't believe you can. However, there are apps that can access the data. One I have used is called SMS Backup & Restore (there's a similar one for call data by the same chap).

When an app is moved to the SD card, the associated data usually doesn't move. Since the data is often large (e.g. games, satnav apps etc.) but the apps themselves aren't, being able to move the small bit isn't very useful.

 

It moves the apk file and and shared object library files, but not the dex files (dalvik cache) or other components of the installed app. So how much of the app it moves depends on the app - can be significant for some, for others only a small fraction.

As lotus says, if a folder needs root permissions to read it that's it.