read-and-write benchmarking damages usb disk and usb port

[xym]

"Read and write benchmarking" in "disk utility" requires to work on a completely empty disk.
1. I tried to format the only volume of the usb disk, "Read and write benchmarking" does not accept this type of "empty".
2. I tried to format the entire driver of the usb disk, this time "Read and write benchmarking" can work on the usb disk.
3. I repeat step 2 to benchmark the second usb disk.
4. I found that neither benchmarked usb disks can be used to create bootable disk.
5. I found that data saved to both usb disks might disappear.
6. I found that if reboot into Windows, any usb disks (including both above-mentioned usb disks and any other usb disks) plugged into the usb ports would cause Windows reboot.

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: gnome-disk-utility 2.32.1-0ubuntu4
ProcVersionSignature: Ubuntu 2.6.38-11.50-generic 2.6.38.8
Uname: Linux 2.6.38-11-generic i686
Architecture: i386
Date: Tue Sep 27 18:06:05 2011
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Release i386 (20110427.1)
ProcEnviron:
 LANGUAGE=zh_CN:en
 PATH=(custom, no user)
 LANG=zh_CN.UTF-8
 SHELL=/bin/bash
SourcePackage: gnome-disk-utility
UpgradeStatus: No upgrade log present (probably fresh install)