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Re: [Xen-users] RE: Does it legal to analysize XEN source code and write a book about it

  • To: echo@xxxxxxxxxxxx
  • From: Tao Shen <taoshen1983@xxxxxxxxx>
  • Date: Mon, 17 Sep 2007 06:11:14 -0600
  • Cc: xen-users@xxxxxxxxxxxxxxxxxxx, Simon Crosby <simon@xxxxxxxxxxxxx>
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  • List-id: Xen user discussion <xen-users.lists.xensource.com>

Tim Post wrote:
3. In other words, you have a non-GPL'd controller application wrapped around an opensourced Xen hypervisor running on a GPL'd but custom Linux distribution made by XenSource. It's crazy how many people on this list say "oh Xen is GPL, but XenEnterprise is not" As Tim Post almost made an impression that XenEnterprise is a complete beast compared to Xen.

Xen is free software. XenExpress, XenEnt, XenServer are not free
software. At what point did I call it a beast?
Tim, I missed a word. "a completely different beast"...and it's my interpretation of what you said about XenSource maintaining two different source trees and etc. Tim, you also are too strict on the following three terms, free, GPL, open source as if you are an IP lawyer. Of course Xen is free, and XenEnterprise is not. The point I am making is that XenEnterprise is 85% based on the core Xen which is free, GPL'd, and source made available by XenSource, and is marketed as if it's a different beast.
XenEnterprise's non-GPL portion is much smaller compared to the GPL'd portion.

Define smaller? Lines of code or cost of development? :) Both must be
considered. Just looking at the screenshots of XenEnt (and the rest) I
can tell you (off the top of my head) your looking at development costs
in the millions.
My definition of smaller is based on perceived value and perceived function. The core free Xen Hypervisor has more perceived value and function than the XenEnterprise the wrapping GUI application. To most people that is. To prove my point, if the Xen Hypervisor is designed correctly, everything you can do in XenEnterprise in a GUI environment, you should be able to do in a command line environment. If you look at the development costs in the millions, it's actually cheap. Development cost really depends on who's developing. People in the US get paid 5 times as much as people in India for example. In the US, 1Mil gives you about 20 programmers for a year on average, maybe 10 good ones for a year. I am sure Xen the hypervisor which is free, had way more programmer-years than the non-GPL'd GUI. And some of the functions that's in the Xen Hypervisor is not enabled in the XenExpress as if XenExpress arbitrarily limit functionality of the core Xen Hypervisor to promote higher priced Server/Enterprise versions even though the Xen Hypervisor hasn't changed.
4. The issues with closed source Windows Paravirtualization is this: whether or not it's merged to the Xen Server/Enterprise source tree(the controller and UI parts, which is not GPL'd) or it's interfaced to the Xen hypervisor source tree(which is GPL'd). From a practical point of view, I don't see how a paravirtualized driver can be non-dependent on the GPL'd Xen Hypervisor.

Someone other than me has to explain to you how hypercalls and program
API's work.
Yes, that's the question you and I both need answers to.
If it's indeed interfaced into the hypervisor, then the windows paravirtualization driver should be open sourced, GPL'd.

That's up to XenSource. They are under no obligation to make those
drivers free. GPL software is not 'open source', every time you say that
I have to ask you to stop.
Ok, Timster. You are correct on that "They are under no obligations to make it free" My statement uses the words "should be" as merely suggestive that perhaps a open standard, API for the windows paravirtualization driver is of more utility and beneficial to both Microsoft, XenSource, and the end user. Of course XenSource doesn't see it that way, and they see it as another way to make money. Legal for sure. Alienating potential customers for sure. Actually I see Xen having a common API for paravirtualization drivers. Then whatever OS you install in a Xen DomU, the OS writer then becomes responsible for writing the Xen DomU paravirtualization driver. For example, Microsoft can be making a Windows XP-Xen Edition with the Xen drivers...etc. But of course if you are XenSource, you would like to have a monopoly of the paravirtualization driver development and charge people for it.

Ok Tim, I got to get 1 hour of sleep before I have to wake up again :) We shall continue the discussion in another time.

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