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I am familiar with USB Mass Storage mode . How exactly is USB Debug mode different from it ?

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up vote 3 down vote accepted

An Android device in "Mass Storage" mode behaves just like a USB flash drive: It presents itself as an block device that can be mounted (i.e "used") by the host PC. Just like an USB stick does.

Additionally "USB Debug Mode" can be enabled, which creates a new USB endpoint for the Android Debug Bridge (adb). This allows an user to get in-deep access to the connected Android device and furthermore it allows the debugging of Apps. This is the reason why you should never attach an Android device with Debug Mode enabled to an untrustworthy PC. As USB is able to provide more then one endpoint per USB device, this "services", Mass Storage and adb, can be used simultaneously.

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Thanks :) Can you elaborate a little on "endpoints" ? I do not know what they mean (in a technical context) . Does the concept of "USB Debug mode" exist for any USB device (like my ipod nano) ? – jsp99 Jan 5 '13 at 13:11
Debugging over USB is just a convenient way to do debug embedded devices of all types. But it's up to the device manufacturer how it's done (or if it all). A USB device can provide different "services" by announcing them on different endpoints. – Flow Jan 5 '13 at 13:16
Ohh .. In the Android world , does every device manufacturer provide a "USB Debug Mode" such that it can be accessed with "ADB" ? – jsp99 Jan 5 '13 at 13:22

USB Debug Mode is used by developers to test their apps. If they connect using USB Debug Mode, they will get debug information about how their app is working on the device.

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Thanks for the answer :) – jsp99 Jan 6 '13 at 3:59

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