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

[Tao Shen <taoshen1983@xxxxxxxxx>]

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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