[linux-elitists] Virtualization

J. Paul Reed preed@sigkill.com
Wed Feb 23 15:47:12 PST 2005


On 23 Feb 2005 at 14:35:25, Greg KH arranged the bits on my disk to say:

> But it can happen, right?  And it _never_ will happen with the current
> vmware modules, right?  That's my point.

No, it could happen with the current VMware modules too.

> No, my main point was that people are trying to work toward a common
> virtual device layer, so that there is no need for vmware modules in the
> future.  You seem to dispute this fact.  Other people at vmware would
> disagree with you.

I dispute this fact because you're confusing host modules with guest
modules; presenting a common virtual device layer has NOTHING to do with
the host-OS modules you're complaining about.

So I'm disputing your (mis-)understanding of how (hosted) virtualization
platforms work.

A common virtual device layer may be something there is collaboration on; I
don't know. But that has to do with *guest* OS kernel modules, and even
then, the ones VMware provides don't have anything to do with device
drivers (like disks, USB, etc.); you can run any modern Linux distro out of
the box with Workstation, without any modules. You claim this isn't true,
and you're just wrong.

Also, if you want to use the "I know people who know more about this than
you who disagree with you"-ploy, feel free to send me the names offline;
I'd be genuinely interested to know if there's some development in that
area I don't know about.

> But real life customers do care about this, as it breaks their service
> contracts.  I'm not talking "purity" here, I'm talking big money.

That's actually an untrue claim as well. It's not a given that it *will*
break their service contract.

> And "have the source" is quite different from "open source", as you well
> know.  Look at the top of the vmware kernel modules.  That explicitly
> states that that code is not "open source" in any form of the word.

And again, this is a values difference; go troll the Debian forums if you
want to complain about the semantics (which, BTW, I completely understand;
I just don't care about them.)

> > It is not used for any of the things you mention.
> > 
> > In some sense, it's a glorified boot loader.
> 
> So it controls access to the hardware under the esx os?

Nope.

> Where does the actual, write the bits out to the scsi controller happen
> from?  Each guest os?

Nope. In ESX, the vmkernel does it; it has its own drivers, which translate
SCSI stuff from the virtualized device layer (which is a BusLogic SCSI
driver, I think) to whatever actual SCSI driver you're using (from the
vmkernel).

When I said "ESX is its own, proprietary kernel that was developed     
entirely in house, and has nothing to do with a 2.4.9 kernel," I meant...
ESX is its own, proprietary kernel that was developed entirely in house,
and has nothing to do with a 2.4.9 kernel.  

> I'm complaining about the fact that the vmware modules will never be in
> the main kernel tree.  And because of that, they are a leach on the
> kernel development process.  They take from our development effort and
> give nothing back.

That's a subjective call; lots of people would disagree with you and would
actually find the position absurd. VMware (or other companies; think nVidia
or some such) don't distract kernel developers from doing their work; sure,
we piggyback on the "platform" that is the OS, but if you're complaining
that entities "piggyback" on the Linux platform, then you should not wonder
why there aren't more Linux users.

You can't say "Hey, Linux is really great; you should use it," and then
when companies port software to it that isn't completely open source, say
"Hey, get the hell out of here, you capitalist assholes."

That's just asinine.

> > What else would you like them to do?
> 
> Work together with other groups to get a common virtual device driver in
> the kernel that everyone can use.  Barring that, move their existing
> drivers into the mainline kernel tree.  Give something back to the
> community, as it is, they are not giving anything.

And this, again, IS JUST COMPLETELY FALSE. You linked to the open source
tarball yourself.

> Their kernel modules are not licensed under the GPL.  That is not legal
> as per the GPL.  Now I'm not going to get into the whole "Linus made an
> exception for kernel modules" argument, as that:
> 	- was for old drivers that were written before Linux existed.
> 	- necessary for connectivity to legacy systems that Linux users
> 	  wanted to connect to (like AFS).
> 	- has been withdrawn in the past few years by Linus himself, and
> 	  explicit stated that it is _not_ what a number of core kernel
> 	  developers want to have happen to their code.
> Remember, loading a module into the kernel is "linking."  See the GPL
> for what that means you have to do with your code if you link.

If you feel so strongly about it, put your money where your mouth is and
file a complaint. People who merely whine for the sake of whining are
annoying.

> > So... why exactly are you complaining again?
> 
> Closed source leaches.  That's why :)

And you people wonder why there's not more commercial software for Linux.

Later,
Paul
------------------------------------------------------------------------
J. Paul Reed -- 0xDF8708F8 || preed@sigkill.com || web.sigkill.com/preed
Math, my dear boy, is nothing more than the lesbian sister of biology.
                                            -- Peter Griffin, Family Guy



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