how to safely remove usb storage? My android 2.3 tablet supports usb. It mounts all usb drives. However there is no mechanism for unmounting in the settings menu.

On direct unplugging usb devices, i get notification " usb mass storage device removed unexpectedly

Is there is an app for unmounting usb storage devices?
It should normally be located within settings>storage>unmount USB storage. Otherwise look within whatever file explorer you are using on the tablet for USB storage, this should indicate that a usb stick etc is using the drive, and hence give you the option to remove/unmount.

There are apps available but these require root access to my knowledge.