> For the complete documentation index, see [llms.txt](https://help.iodd.kr/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.iodd.kr/bootable-virtual-drive/virtual-drive-vhd/advanced-vhd-tool-functions.md).

# Advanced VHD Tool++ Functions

**VHD Tool++** is a **Windows-exclusive application** for managing fixed-size VHD files used by IODD virtual drive features. Beyond simple VHD creation, it includes maintenance tools for keeping ISO, VHD, and disk image workflows compatible with IODD boot and mount requirements.

Use these advanced functions when you need to convert a raw image, increase an existing VHD size, remove file fragmentation, or upload a virtual drive image to the IODD without breaking mount compatibility.

## Available Functions

* **\[Convert]**: Converts a general disk dump image file into a fixed-size VHD file.
* **\[Extend]**: Increases the size of an existing fixed VHD file.
* **\[Defragment]**: Specifically defragments a single file on the IODD to ensure it is contiguous (0 fragments).
* **\[Upload]**: Copies a file from your PC to the IODD while ensuring it remains unfragmented during the transfer.
* **\[Write To HDD] (Expert Only)**: Performs a sector-to-sector physical duplication of an image file to the internal HDD. **Note**: This function only supports the **NTFS**, **exFAT** file system.

## Write To HDD Warning

{% hint style="danger" %}
**WARNING**: This will permanently delete ALL data on the internal drive. It is only recommended for advanced users performing raw disk operations.
{% endhint %}