Demo for PowerShell script to create ISO using IMAPI COM component, as a simplification for StackOverflow answer http://stackoverflow.com/a/8325316/223837

createiso-demo.ps1

# Inspiration from
#
#   http://blogs.msdn.com/b/opticalstorage/archive/2010/08/13/writing-optical-discs-using-imapi-2-in-powershell.aspx
#
# and
#
#   http://tools.start-automating.com/Install-ExportISOCommand/
#
# with help from
#
#   http://stackoverflow.com/a/9802807/223837

function WriteIStreamToFile([__ComObject] $istream, [string] $fileName)
{
	# NOTE: We cannot use [System.Runtime.InteropServices.ComTypes.IStream],
	# since PowerShell apparently cannot convert an IStream COM object to this
	# Powershell type.  (See http://stackoverflow.com/a/9037299/223837 for
	# details.)
	#
	# It turns out that .NET/CLR _can_ do this conversion.
	#
	# That is the reason why method FileUtil.WriteIStreamToFile(), below,
	# takes an object, and casts it to an IStream, instead of directly
	# taking an IStream inputStream argument.

	$cp = New-Object CodeDom.Compiler.CompilerParameters             
	$cp.CompilerOptions = "/unsafe"
	$cp.WarningLevel = 4
	$cp.TreatWarningsAsErrors = $true

	Add-Type -CompilerParameters $cp -TypeDefinition @"
		using System;
		using System.IO;
		using System.Runtime.InteropServices.ComTypes;

		namespace My
		{

			public static class FileUtil {
				public static void WriteIStreamToFile(object i, string fileName) {
					IStream inputStream = i as IStream;
					FileStream outputFileStream = File.OpenWrite(fileName);
					int bytesRead = 0;
					int offset = 0;
					byte[] data;
					do {
						data = Read(inputStream, 2048, out bytesRead);  
						outputFileStream.Write(data, 0, bytesRead);
						offset += bytesRead;
					} while (bytesRead == 2048);
					outputFileStream.Flush();
					outputFileStream.Close();
				}

				unsafe static private byte[] Read(IStream stream, int toRead, out int read) {
				    byte[] buffer = new byte[toRead];
				    int bytesRead = 0;
				    int* ptr = &bytesRead;
				    stream.Read(buffer, toRead, (IntPtr)ptr);   
				    read = bytesRead;
				    return buffer;
				} 
			}

		}
"@

	[My.FileUtil]::WriteIStreamToFile($istream, $fileName)
}

# Constants from http://msdn.microsoft.com/en-us/library/windows/desktop/aa364840.aspx
$FsiFileSystemISO9660   = 1
$FsiFileSystemJoliet    = 2


$fsi = New-Object -ComObject IMAPI2FS.MsftFileSystemImage

$fsi.FileSystemsToCreate = $FsiFileSystemISO9660 + $FsiFileSystemJoliet
$fsi.VolumeName = "demo image"
$fsi.Root.AddTree("my folder", $true)

WriteIStreamToFile $fsi.CreateResultImage().ImageStream "demo.iso"

Under which license is this code?

@newkit Apologies for the delay, I missed this comment completely. This code is in the public domain.

Doesn't work in PS 6.2.2:

Add-Type : A parameter cannot be found that matches parameter name 'CompilerParameters'.
At E:\work\MSPV\New_ISOfile.ps1:19 char:11
+     Add-Type -CompilerParameters $cp -TypeDefinition @"
+              ~~~~~~~~~~~~~~~~~~~
+ CategoryInfo          : InvalidArgument: (:) [Add-Type], ParameterBindingException
+ FullyQualifiedErrorId : NamedParameterNotFound,Microsoft.PowerShell.Commands.AddTypeCommand

Unable to find type [My.FileUtil].
At E:\work\MSPV\New_ISOfile.ps1:52 char:2
+     [My.FileUtil]::WriteIStreamToFile($istream, $fileName)
+     ~~~~~~~~~~~~~
+ CategoryInfo          : InvalidOperation: (My.FileUtil:TypeName) [], RuntimeException
+ FullyQualifiedErrorId : TypeNotFound

Corresponding (see just above) question on Stack Overflow:
https://stackoverflow.com/questions/57754249/code-works-perfectly-in-powershell-5-but-not-in-powershell-6

@illusive-man see here
https://gist.github.com/AbdElraoufSabri/bb202bdea4e19db0e4c5e4a2f12917ae

@AbdElraoufSabri, thanks. That's good. More universal approach. I'll give it a go.

As for above it's working as well. We only need to check PS Version and use corresponding Compiler Options/Parameters. Works like a charm and pretty fast.

 $PSV = $PSVersionTable.PSVersion.Major

    if ($PSV -ge 6) {
        $cp = "/unsafe"
        Add-Type -CompilerOptions $cp -TypeDefinition $typedef
    }
    elseif ($PSV -le 5 -and $PSV -ge 3) {
        $cp = New-Object CodeDom.Compiler.CompilerParameters             
        $cp.CompilerOptions = "/unsafe"
        $cp.WarningLevel = 4
        $cp.TreatWarningsAsErrors = $true
        Add-Type --CompilerParameters $cp -TypeDefinition $typedef
    }
....
  Write IStream to File here.
....