On my old Android phone (Mototola Droid 3), when I plugged my phone into the USB port, it mounted as an external HD, giving me a drive letter and full filesystem access. My new Samsung Galaxy S4 does not do that.
It took me awhile to realize this was an “enhancement” to the Android OS, and not a defect in my phone or the way I wa a using it.
For the old Android phones, I was using what’s called USB/UMS/MSC mode. That lets me mount the phone’s SD card as a full Windows drive. I get a drive letter. The SD card is inaccessible on the phone while it’s plugged into my USB port.
Theoretically, I could edit the SD card contents and mess up my phone, while it’s plugged into the USB port.
The new Android phones support MTP Transfer mode instead of USB mode. What’s the difference? I can still access the SD card while it’s mounted in Windows. However, I don’t get FULL access to the phone’s storage, only the bits that the Android OS chooses to allow. (Basically, I have access to everything except the protected OS directories.) Also, I don’t get a drive letter. Instead, it’s mounted as a generic Windows drive.
Why does this matter? I CAN’T EDIT TXT (notepad) FILES AND SAVE THEM DIRECTLY BACK TO THE PHONE!
On the old Android phone, I could open a text file in notepad (usually blog drafts), and then save them directly back to the phone.
With my new phone, I can open a text file in notepad. However, I CAN’T DIRECTLY SAVE IT BACK TO THE PHONE. I have to save it as a file on my local PC, and then copy it over to the phone!
However, I’m not sure if this is a bug in the Android OS, or a bug in Windows, or a combination of the two. I should be able to open a file in notepad, edit it, and save it directly back to the phone.
By removing USB mount mode and switching to MTP mode, I lost one of the big uses of my phone, easily preparing blog drafts! Now, I have to edit the file, save it to my PC, and then copy it back to the phone!
I also have a warning for any Samsung Galaxy S4 users. DON’T INSTALL THE DRIVER THAT COMES WITH THE PHONE! I tried that, and I wasn’t able to connect the phone via USB anymore! Instead, use the default Windows 7 driver.