Enable USB Mass Storage on Pandaboard running android 4.4.2
Aashish Patel
Aashish Patel
I did some more digging and found out that google has removed UMS support after honeycomb and uses MTP and PTP for file transfer instead.
Earlier Android used to have /data partition for app data and /sdcard for movies, music and rest. Say you are an app freak and have installed lots of apps, what happens in /data fills up but still you can't use space from your /sdcard as it's a separate partition. Now what Google has done is used unified file system. So that you can share space between /sdcard and /data. USB mounts storage on host and gives entire block level access to the host. If this is done the partition is unmounted from your phone. It was fine when /sdcard was separate now since both /data and /sdcard reside on same partition Android can't afford to allow full block access to another host.
I also found out that Microsoft holds patents for long file name support on FAT filesystem. That's one patent for which they demand royalties from OEM's. If you use USB mount, you need to format your /sdcard as FAT because most users use windows. If you use FAT, you need to pay MS or risk a lawsuit. With MTP, Google can use ext3/4 btrfs whatever they please and there is no risk of lawsuit.
Finally, formatting filesystem with ext3/4 instead of FAT gives lots of read/write improvements since Android uses linux kernel.
Also MTP is still in developing phase like other features and has issues with larger files.