VBoxRawdisk is a small utility that makes it a little easier to generate the raw disk (VMDK) file required to load a real disk drive into VirtualBox. It implements the steps described in Section 9 of the VirtualBox manual - 126.96.36.199 Access to entire physical hard disk.
When the utility is initiated it scans the physical drives attached to your Mac and presents a table similar to that used by Disk Utility. When a drive is selected, key attributes of that device are displayed, enabling you to determine which drive contains the data you wish to use in VirtualBox.
VBoxRawdisk also reads the VirtualBox registry to determine which virtual machines you have configured. When a disk has been selected, the menu of virtual machines is enabled and you can proceed with generating the VMDK file.
Note: While the software is classified as free, it is actually donationware. Please consider making a donation to help support development.