Skip to content


Repository files navigation

Project Description

Build status

DiscUtils is a .NET library to read and write ISO files and Virtual Machine disk files (VHD, VDI, XVA, VMDK, etc). DiscUtils is developed in C# with no native code (or P/Invoke).

Implementation of the ISO, UDF, FAT and NTFS file systems is now fairly stable. VHD, XVA, VMDK and VDI disk formats are implemented, as well as read/write Registry support. The library also includes a simple iSCSI initiator, for accessing disks via iSCSI and an NFS client implementation.

Note: this is a fork of, which itself is a fork of


See more up to date documentation at the Wiki

Implementation in this repository

This repository has performed a few changes to the core DiscUtils library. For starters, all projects have been converted to .NET Core, and are targeting .NET 2.0 through 5.0, in addition to .NET Standard 2.0 (thanks Quamotion).

The DiscUtils library has been split into 25 independent projects, which can function without the others present. This reduces the "cost" of having DiscUtils immensely, as we're down from the 1 MB binary it used to be.

To work with this, four Meta packages have been created:

  • DiscUtils.Complete: Everything, like before
  • DiscUtils.Containers: such as VMDK, VHD, VHDX
  • DiscUtils.FileSystems: such as NTFS, FAT, EXT
  • DiscUtils.Transports: such as NFS

Note on detections

DiscUtils has a number of detection helpers. These provide services like "which filesystem is this stream?". For this to work, you must register your filesystem providers with the DiscUtils core. To do this, call:


Where assembly is the assembly you wish to register. Note that the metapackages have helpers:

SetupHelper.SetupComplete(); // From DiscUtils.Complete
SetupHelper.SetupContainers(); // From DiscUtils.Containers
SetupHelper.SetupFileSystems(); // From DiscUtils.FileSystems
SetupHelper.SetupTransports(); // From DiscUtils.Transports

How to use the Library

Here's a few really simple examples.

How to create a new ISO:

CDBuilder builder = new CDBuilder();
builder.UseJoliet = true;
builder.VolumeIdentifier = "A_SAMPLE_DISK";
builder.AddFile(@"Folder\Hello.txt", Encoding.ASCII.GetBytes("Hello World!"));

You can add files as byte arrays (shown above), as files from the Windows filesystem, or as a Stream. By using a different form of Build, you can get a Stream to the ISO file, rather than writing it to the Windows filesystem.

How to extract a file from an ISO:

using (FileStream isoStream = File.Open(@"C:\temp\sample.iso"))
  CDReader cd = new CDReader(isoStream, true);
  Stream fileStream = cd.OpenFile(@"Folder\Hello.txt", FileMode.Open);
  // Use fileStream...

You can also browse through the directory hierarchy, starting at cd.Root.

How to create a virtual hard disk:

long diskSize = 30 * 1024 * 1024; //30MB
using (Stream vhdStream = File.Create(@"C:\TEMP\mydisk.vhd"))
    Disk disk = Disk.InitializeDynamic(vhdStream, diskSize);
    BiosPartitionTable.Initialize(disk, WellKnownPartitionType.WindowsFat);
    using (FatFileSystem fs = FatFileSystem.FormatPartition(disk, 0, null))
        // do other things with the file system...

As with ISOs, you can browse the file system, starting at fs.Root.

How to create a virtual floppy disk:

using (FileStream fs = File.Create(@"myfloppy.vfd"))
    using (FatFileSystem floppy = FatFileSystem.FormatFloppy(fs, FloppyDiskType.HighDensity, "MY FLOPPY  "))
        using (Stream s = floppy.OpenFile("foo.txt", FileMode.Create))
            // Use stream...

Again, start browsing the file system at floppy.Root.

Development releases

Automated CI builds are available on Myget. Add this source to your nuget configuration:

.. or add this to a NuGet.Config file (Casing important on linux), in your repository:

<?xml version="1.0" encoding="utf-8"?>
    <add key="DiscUtils" value="" />