检测usb的U盘的盘符,适用于移动硬盘，可用于U盘编程。-U-test usb disk drive letter, for mobile hard disk, U disk can be used for programming.

Delphi:Delphi判断驱动器类型，可判断出所选择的驱动器是否是可移动磁盘、硬盘、或软盘、光驱等类型，选择任意一个驱动器后，点击“判断驱动器”按钮，即可在Label处显示该驱动器的类型。 -Delphi: Delphi determine drive types, you can determine the selected drive is a removable disk, hard disk, or floppy disk, CD-ROM, such as type, selec