Flash device name. This name is used to refer to the
device within the system. Flash operations get directed
to a device based on this name.
The system has a concept of a default device.
This would be the primary or most used device in case of
multiple devices. The system directs an operation to the
default device whenever a device name is not specified.
The device name is therefore mandatory except when the
operation is being done on the default device, or,
the system supports only a single Flash device.
The device name will always be available for a
removable device, even when the device has been removed.