Is VMware's ESX server derived from Linux?

There nothing like a huge IPO and being described as the hottest tech stock since Google to attract attention to your company, and it seems that this is what's happened to VMware.  Writing on VentureCake blog, Linux guru Mike MacCana is claiming that VMware's ESX server application is derived from Linux, and because of this cannot legally be redistributed as proprietary software.

The issue, as MacCana describes it, is that when a system running ESX boots up, the kernel is Linux.

Here’s how MacCana sees the problem:

Proprietary drivers for Linux kernel have an interesting licensing situation. Unlike the license for higher level libraries, which allow those libraries to be used by both Open Source and proprietary software, the license for the Linux kernel specifies that software based on the Linux kernel must be licensed under the same license.

So the core of MacCana’s argument is that if the kernel relies on Linux, it has to be open source, yet ESX is not.  If the kernel didn’t require Linux to load it could be considered to be derivative and therefore could be legally distributed.

The problem goes back a fair while.  Back in August 2006 there was a post on the Linux kernel mailing list made by the Linux SCSI storage maintainer, Christopher Helwig in which he responds to a post from VMware's Zachary Amsden:

Until you stop violating our copyrights with the VMWare ESX support nothing is going to be supported. So could you please stop abusing the Linux code illegally in your projects so I don't have to sue you, or at least piss off and don't expect us to support you in violating our copyrights. I know this isn't your fault, but please get the VMware/EMC legal department to fix it up first.

There was no reply from Amsden.

VMware has drawn attention to itself.  it’ll be interesting to see where this goes.