VDI is a disk image format used by VirtualBox that can also be mounted and
used with diskimage.device. The main advantage of VDI over raw image formats
like HDF f.e. is that it supports sparse or dynamic disk images where only
blocks that actually contain data are stored inside the VDI file.

Installation:

Copy vditool SYS:C/

Usage:

vditool <command> <.vdi file> [options]
Commands:
  create          Create a new .vdi file
  info            List information about .vdi file
  compact         Compact a dynamic .vdi file
  convertfromraw  Convert raw (.hdf) to .vdi file
  converttoraw    Convert .vdi to raw (.hdf) file
Command syntax:
  vditool create <.vdi file> [fixed|dynamic] <size>
  vditool info <.vdi file>
  vditool compact <.vdi file>
  vditool convertfromraw <.vdi file> <raw file> [fixed|dynamic]
  vditool converttoraw <.vdi file> <raw file>

The create command creates an empty fixed or dynamic VDI file of the size
specified (in GiB).

To create a 30 GiB dynamic VDI file:
vditool create empty.vdi dynamic 30

The info command lists information about the VDI file like the type (fixed/
dynamic), sector size, disk size, block size, number of blocks and number of
blocks currently in use.

To list info about harddisk.vdi:
vditool info harddisk.vdi

The compact command removes any blocks in a VDI file that contains only zero
bytes and then resizes the file. This operation is done in place and is not
well tested at the moment so it is recommended to do a backup of the VDI file
first before attempting this.

To compact the VDI file system.vdi:
vditool compact system.vdi

In order for compacting to be of any real use you will also need a program
that writes zero to any sectors unused by the filesystem(s) (AFAIK no such
tool exists for AmigaOS yet).

To convert amigaos3.hdf to amigaos3.vdi:
vditool convertfromraw amigaos3.vdi amigaos3.hdf

Convert back to raw (.hdf) format:
vditool converttoraw amigaos3.vdi amigaos3.hdf

Changes:

1.2 (25-May-2011)
 - Improved progress displays for compacting
 - Added break signal checks for compacting
 - Added convertfromraw and converttoraw commands

1.1 (22-May-2011)
 - First released version