Virtual Disk Image (VDI)

From ForensicsWiki
Revision as of 08:30, 25 February 2016 by Joachim Metz (Talk | contribs) (External Links)

Jump to: navigation, search

Information icon.png

Please help to improve this article by expanding it.
Further information might be found on the discussion page.

Image structure

All VirtualBox Virtual Disk Image (.vdi) files are structured in essentially the same way:

  • A header descriptor (512 bytes)
  • An image block map: If the (maximum) size of the virtual HDD is N MB, then this map is 4N bytes long.
  • Block alignment padding: The header format allows for padding between the image block map and the image blocks, and (as of version 1.6.2) the CreateVDI function adds padding after the map to ensure that the first image block begins on a 512byte sector boundary. Since the allocation unit on both NTFS and Ext3 file systems is 4096 bytes, you will therefore get slightly better performance (typically a few %) if you make your VDIs (1024N – 128) MByte long.
  • Up to N x 1MByte image blocks.

See Also

External Links

  • [1], All About VDI's (VirtualBox forums)