Conservancy's compliance conclusions.  Christoph then began his own

   enforcement effort with legal representation from Till Jaeger.  Christoph has

   been unable to achieve compliance, either, through his negotiations in

   2014.  VMware's last offer was a proposal for a settlement agreement that VMware would

   only provide if Christoph signed an NDA, and Christoph chose (quite

   reasonably) not to sign an NDA merely to look at the settlement offer.</p>

 <p>Thus, this lawsuit comes after years of negotiations by Conservancy to

 achieve compliance — negotiations that ended in an outright refusal by

 VMware's lawyers to comply.  Those events were then followed by a year of

   work by Christoph and Till to achieve compliance in a separate action.</p>

 <p>Simply put, Conservancy and Christoph fully exhausted every possible

 non-litigation strategy and tactic to convince VMware to do the right thing

 before filing this litigation.</p>

  </dd>    

  <dt>What are VMware's primary defenses for their alleged copyright

    infringement?</dt>

  <dd>With the guidance of counsel, Christoph was able to provide Conservancy

  with a high-level summary of VMware's statement of defense, which we share

  in this FAQ.  Specifically, VMware's statement of defense primarily focuses

  on two issues.  First, VMware questions Christoph's copyright interest in

  the Linux kernel and his right to bring this action.  Second, VMware claims

  vmklinux is an “interoperability module” which communicates

  through a stable interface called VMK API.</dd>

  <dt>How did Christoph respond to VMware's statement of defense?</dt>

  <dd>Christoph's response discusses his extensive contributions to the Linux

  kernel and disputes the technical merits of VMware's assertions. The

  response points out that vmklinux is <strong>not</strong> an

  interoperability module, but rather an arbitrary separation of the Linux

  derived module from vmkernel.   Specifically, vmklinux is nonfunctional

  with any non-ESX OS, and vmklinux is tied intimately to a specific version

  of ESXi.  Vmklinux does not allow reuse of unmodified Linux drivers in

  binary or source form.  Christoph further points out that if the Court

  allows proprietarization of an arbitrary split portion of GPL'd computer

  programs, it could allow redistributors to trivially bypass the strong

  copyleft terms found in the GPL.  Finally, the response explains that

  vmkernel and vmklinux don't “communicate over an interface”,

  rather they run in the same process as a single computer program.  Thus,

  VMK API, as used by vmklinux, is not an “interface” as set

  forth in

  the <a href="http://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX:32009L0024&from=EN">EU

      Directive 2009/24/EC</a>.</dd>

  their kernel?</dt>

  <dd>

  <p id="diagram">

    Conservancy prepared this diagram to show the technical situation as we

    understand it.  The diagram compares the technical architecture of a full,

    running Linux kernel with a full, running VMware kernel:

    <p>

      <a href="/linux-compliance/linux-vs-vmkernel_en.png">

    <img class="inside-faq" alt="[Diagram of Linux and VMware running kernels]" src="/linux-compliance/linux-vs-vmkernel_en_scaled.png" /></a>

    </p>

    <p>If you want to download the diagram, it's available

    in <a href="/linux-compliance/linux-vs-vmkernel_en.svg">SVG

    (English)</a>, <a href="/linux-compliance/linux-vs-vmkernel_en.png">PNG

    (English)</a>, <a href="/linux-compliance/linux-vs-vmkernel_de.svg">SVG

    (German)</a>, and <a href="/linux-compliance/linux-vs-vmkernel_de.png">PNG

    (German)</a>.</p>

  </dd>

  <dt>Can you explain further in words (rather than a picture) about the central

  component in ESXi that the lawsuit alleges violates the GPL?</dt>

<dd>

    <p>The GPL violation at issue involves VMware's ESXi product.

    Conservancy independently reviewed ESXi 5.5 and its incomplete

      <abbr title="complete, corresponding source">CCS</abbr>

    release as part of our GPL enforcement efforts described above.</p>

    <p>Conservancy's preliminary investigation indicated that the operating

    system kernel of VMware ESXi product consists of three key components:

        <ul>

          <li> the proprietary component &ldquo;vmkernel&rdquo;, which is

            released in binary form only,</li>

            <li>the kernel module &ldquo;vmklinux&rdquo;, which contains modified Linux

Code, and for which (at least some) source code is provided.

            <li>other kernel modules with device drivers, most of which are

            modified Linux drivers, and for which (at least some) source code

              is provided.</li>

        </ul>

    <p>Conservancy examined the incomplete CCS alongside the

           binary “vmkernel” component.  Such examination indicates that functions

           in “vmkernel” do make function calls to Linux's kernel code

      in the usual way for a single program written in C.</p></dd>

    <dt>Doesn't VMware's &ldquo;shim layer&rdquo; insulate them from GPL

    obligations and allow them to keep certain code in their kernel

    proprietary?</dt>