.NET (Core and Framework)

Private Sub write(ByVal startpos As Long, ByVal lstream As Byte())
        Dim numberofBlocks As System.UInt32
        numberofBlocks = GetBlocksNumber(lstream.Length)
        TapeSeek(startpos)
        Dim arrayToWrite(numberofBlocks * BlockSize() - 1) As Byte
        Array.Copy(lstream, arrayToWrite, lstream.Length)
        m_stream.Write(arrayToWrite, 0, arrayToWrite.Length)
        m_stream.Flush()
        REM  Dim nbr As System.Int32
        REM nbr = 0
        REM retval = WriteFile(m_handleValue, arrayToWrite, 512, nbr, Nothing)
    End Sub

    Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click        
        Dim selecteddrive As String
        selecteddrive = "\\.\" + ComboBox1.SelectedItem.ToString
        TapeLoad(selecteddrive)
        Dim mediainfo As New DRIVE_INFO
        Dim msize As Integer
        Dim ptr As System.IntPtr
        Dim ptr2 As System.IntPtr
        Dim ptr3 As System.IntPtr
        Dim mediasize2 As New TAPE_MEDIA_INFO
        Dim mediasize As New TAPE_SET_MEDIA_PARAMETERS
        ptr = IntPtr.Zero
        msize = Marshal.SizeOf(mediainfo)
        ptr = Marshal.AllocHGlobal(msize)
        Dim deleteold As Boolean
        deleteold = True
        Marshal.StructureToPtr(mediainfo, ptr, deleteold)
        retval = GetTapeParameters(m_handleValue, GET_TAPE_DRIVE_INFORMATION, msize, ptr)
        Marshal.PtrToStructure(ptr, mediainfo)
        If mediainfo.FeaturesLow And TAPE_DRIVE_VARIABLE_BLOCK Then
            ptr2 = IntPtr.Zero
            msize = Marshal.SizeOf(mediasize)
            ptr2 = Marshal.AllocHGlobal(msize)
            mediasize.BlockSize = mediainfo.MaximumBlockSize
            Marshal.StructureToPtr(mediasize, ptr2, deleteold)
            retval = SetTapeParameters(m_handleValue, SET_TAPE_MEDIA_INFORMATION, ptr2)
            MsgBox("Setting Variable Tape Block Size to Maximum Value of: " + Str(mediainfo.MaximumBlockSize) + " Bytes")
            Marshal.PtrToStructure(ptr2, mediasize)
            Dim myblocksize As System.Int32
            myblocksize = BlockSize()
        End If
        MsgBox("Using Maximum Block Size of: " + Str(mediainfo.MaximumBlockSize) + " Bytes")
        Marshal.FreeHGlobal(ptr)
        Marshal.FreeHGlobal(ptr2)
        Marshal.FreeHGlobal(ptr3)
        Dim mystream(BlockSize() - 1) As Byte
        mystream(1) = 99
        mystream(511) = 99
        write(101, mystream)
        TapeDriveClose()
    End Sub