What are the differences among Internal storage, external storage, sd card and removable storage?

Question

From the official documentation:

Using the External Storage

Every Android-compatible device supports a shared \"external storage\" that

Answer 1

The Internal and External Storage terminology according to Google/official Android docs is quite different from what we think.

According to official Android docs:-

Internal Storage: By default, files saved to the internal storage are private to your application and other applications cannot access them. When the user uninstalls your application, these files are removed/deleted. Your app user also can't access them using file manager; even after enabling "show hidden files" option in file manager. To access files in Internal Storage, you have to root your Android phone. So, this is NOT what we think as internal memory of the phone - Nexus 5's 32 GB internal memory.

External Storage:

This can be a removable storage media (such as an SD card) or an internal (non-removable) storage

That means, both storage types like Nexus 6P's 64 GB internal memory and removable microSD card which we insert in phone's card slot are considered as External Storage.

Removable Storage means just microSD card storage, not the internal memory.

To store your app files in SD card, you may use File[] getExternalFilesDirs (String type) method in Context class. Generally, second returned path would be the storage path for microSD card (if any).

Note: I have edited - made my answer more useful after @Tunaki's comment.