  This bachelor thesis describes the implementation of an Android framework to
access mass storage devices over the USB interface of a smartphone. First the
basics of USB (i.e. interfaces, endpoints and USB On the go) and accessing USB
devices via the official Android API are discussed. Next the USB mass storage
class is explained, which was de- signed by the USB-IF to access mobile mass
storage like USB pen drives or external HDDs. For communication with mass
storage devices, most important are the bulk-only transfer and the SCSI
transparent command set. Furthermore file systems, for accessing directo- ries
and files, are described. This thesis focuses on the FAT32 file system from
Microsoft, because it is the most commonly used file system on such devices.
After the theory part it is time to look at the implementation of the
framework. In this section, the first concern is the purpose in general. Then
the architecture of the framework and the actual implementation are presented.
Important parts are discussed in detail. The thesis finishes with an overview
of the test results on various Android devices, a short conclusion and an
outlook to future developments. Moreover the current status of the developed
framework is visualized.
