VMDK Descriptor

What is the maximum possible length of a disk descriptor file?

        Dim ae As New System.Text.ASCIIEncoding()

        Dim ar() As Byte = New Byte(1312) {}

        Dim i As Integer

        For i = 0 To 1200

            ar(i) = readFs.ReadByte()

        Next

        Console.Write(ae.GetString(ar, 512, 800))