Simple Disk Imager

The goal of this project is to provide a simple Windows program that write USB disk images to USB thumb drives.

Prebuilt binaries are avail in the GitHub Release page.

Unlike Win32 Disk Imager, this program will slightly modify the contents of image before writing. Specifically, GPT partitions headers will be updated based on the drive geometry. Additionally the partitioning information information is only written to the disk after all data has been written, which prevents Windows from trying to automatically mount the disk before the imaging is complete.

Unlike Rufus, this tool will not try to modify an CD ROM image (a.k.a. ISO image) to work correctly on a USB thumb drive.

Screenshot

Supported partition formats

• Master Boot Record (MBR)
• GUID Partition Table (GPT)

Supported disk images formats

• Raw
• Virtual Hard Disk (VHD)

The disk image loading code is based on ZFS Sharp, so several more formats could be potentially ported over, such as VHDX and VDI.

Building

Requires Visual Studio 2019 or later. Run build.cmd. If you are using a Visual Studio Command Prompt, it will use the compilers from that, otherwise it will locate the latest version of Visual Studio to build.

TODO

• Set up automated build and release system.
• Prevent Windows from trying to mount the device by using FSCTL_LOCK_VOLUME. This is a little difficult as FSCTL_LOCK_VOLUME operates on volumes. Zero or more volumes can be on each disk.
• Add support for writing ISO images to thumb drives. At least for EFI-based ISO images like Windows and Ubuntu, it is merely necessary to format the thumb drive as FAT and extract the files from the ISO to the FAT drive. There is the added wrinkle that FAT32 can't support files larger than 4GB, so large files like the install.wim in Windows installations have to be dealt with. There is a proof of concept of extracting and splitting files in ConvertEfiIsoToFat program. The main downsides to this approach are:
  • It will only work with ISO images that support booting on EFI.
  • The resulting image will no longer have the ability to boot on a BIOS system (if it had it before).
  • The approach of formatting and extracting files does not cleanly fit into the current application architecture. It would probably require more platform-specific code to do the partitioning and mounting of a volume to enable mounting. Alternatively, I could create a temporary disk image of a FAT file system and then write that instead of the given ISO. Currently DiscUtils does not support long file names in FAT, which makes this harder.
• Use custom COM type instead of those generated by TLBIMP.exe. Currently several types are marked with ComConversionLossAttribute. This blocks querying drive letters. There may also be a stack corruption problem with _VDS_ASYNC_OUTPUT.
• Implement the drive add/remove event on top of the COM interface instead of listening for Windows messages. This would make the library easier to use in new GUIS.
• Research if there is a way to get a round the apparent single-threaded nature of VDS. Currently if there is a "clean all" operation ongoing, every query to VDS blocks.
• Gracefully handle errors during device enumeration. Currently if a device is stuck in "clean all", pulling out the device will result in an exception in blocked call to IEnumVdsObject.Next.
• Use something like ILMerge to create a single file executable.
• Consider using a system like MVVM to move the GUI logic out of the GUI itself.
• Consider supporting operating systems other than Windows.