Ravi Arimilli, IBM Fellow and Chief Architect

Ravi Aarimilli
In 2000, IBM embarked on an ambitious strategy to boost
Unix server market share after years of watching its sales suffer at the
hands of rivals HP and Sun Microsystems.

The company trotted out its first Power4 machines in 2001 and
promptly set about devouring market share from its rivals, watching its plot
in the Unix land grow from 15 percent to 25 percent between 2000 and 2004,
according to IDC.

But that wasn’t enough. Big Blue continued to advance its processor
roadmap, bringing it more closely into alignment with its company-wide
initiative to provide computing resources on-demand. Customers have been
asking vendors for such dynamic computing capabilities to help curb data center complexity.

The vendor unveiled
Unix servers based on its new Power5 processors with great fanfare and
competitive sniping
more than two weeks ago, promising “jaw-dropping” performance.

The machines, available to
the public August 31, were developed under the
auspices of IBM Fellow and Chief Architect Ravi Arimilli. The engineer
discussed the fruits of four years of labor on the Power5 with
internetnews.com, as well as what IBM has in store for the future.

Q: You were given the task of making up lost ground in the Unix
server market after years of being bested by HP and Sun. What is IBM
doing to set itself apart?

We’ll tie the technology and say things like ‘Is there any way we can do a
hybrid technology and add some silicon germanium into it?’ We’re always
pushing value-adds. We were the first to come out with SOI [Silicon on
Insulator]. My team also looks beyond the microprocessor core to other
details. For example, my team had meetings with customers where we listened
to them tell us how they needed Linux on Power to be better than Linux on
Power4 was. We spent literally three or four weeks at different moments in our days
with the Linux kernel team — Linus Torvalds, Andrew Morton. They had a gun
full of stuff that they wanted us to change and it was a great brainstorming

I want my team to be aware of how the bricks they are laying get
used up here by the Linux operating system guys, by the middleware guys, by
the WebSphere guys. I doubt the Sun or HP processor guys had meetings with
Linus Torvalds. We have the ability to have meetings with these guys to
improve the technology.

Q: Were these the meetings of the IT minds between IBM and customers?

Yes. On Power5, we really had time to use more technologies and sit back and
talk to, for example, the CIO from American Express, the CIO from State
Farm, the CIO from Home Depot. They’d get surprised because you’d walk in
and ask them what they want to see in their IT farm. They’re not used to
anyone doing that, except for individual component vendors meeting them like
a DB2 guy, or an Oracle guy.

We came in and hit them at a broad scope. The
new model at IBM as a company is outbound — we brainstorm with them. It
used to be that the operating system would adapt to whatever the hardware

Linux has to run on so many architectures, and I learned at these
meetings how difficult it is for an open source, multi-architecture system to
be good. When you see that, you realize you have to help these guys do what
they do better rather than them changing their design for you. So Power5 is
heavily optimized towards Linux.

Q: For Power5, you and your team came up with a lot of features you are
clearly proud of, including the micro-partitioning virtualization. VMware
gets a lot of praise for what they’ve been able to do on the Intel side. But
now you’ve been able to do something on the Unix side that no one has seen,
such as run as many as 10 virtual servers on a processor.

Let’s talk about VMware. If you look at what we’ve done on the hardware, we
have truly decoupled the operating systems. But while we say decoupled, I
think there is a misnomer here. For example, I can run
z/OS on my laptop and I can run Linux and Windows. You can run multiple
operating systems on one processor today on your laptop. That’s really what
I call the emulated model — not native to the metal model.

So many people
have done many emulated models where you can have three different Windows
systems on a PC. If you look at what VMware does, they do more of that kind of
thing, even though they talk about partitions per processor. They’re not
native on the hardware; they’re emulated. What we did is actually become
native on the hardware, so when you run a partition in this model vs. the
direct-attached model, you lose no performance. That is not the case with
VMware at all.

Q: So you’re saying they’re not true virtualization?

They’re not true virtualization in the way that I think it should be
defined. I have the same analogy for the many software vendors that make
software that runs on top of your laptop that can run z/OS. We actually made
microprocessor changes to allow many things to run native on the metal but
are invisible to which metal they’re on. And that’s true virtualization. If
you just peel it away, I can run 100 operating systems on one processor.
That’s not virtualization; that’s just emulated fashion.

Q: What features in the Power5 systems reflect the company’s broad strategy
of on-demand?

The major thing I’d day that ties into that is the virtualization. One is
the fact that we have micropartitioning. The other is the fact that we are
virtualizing the whole system. One thing we haven’t done, which is the next
step to on-demand, is something that will appear on Power5+ next year: Let’s
say I buy six SMP machines, with 20 partitions per SMP. Well, it’s great that
those partitions residing within the SMP are fully virtual, with all of the
I/O and memory and so forth. But the real idea of true, multi-system
virtualization is making those partitions run anywhere. Not just on a
physical SMP, but on any domain.

Now to do that, there are some obvious
rules. All of the stuff that the SMP connects into, like the storage and
network, must be twin-tailed to the other machine. It’s multi-system
virtualization, so active partitions migrate from one cluster to another.
That ties into on-demand in my view. Because on-demand needs to do all of
that stuff. We have done stepping stones to the pieces of it. But true
on-demand can run any place on the Internet. Also, on-demand has the model
of being network-based, which I think is its weakest link. That will go down
once we get to multi-system virtualization where there will be more seamless
migration. We’re getting closer and closer. It’s all coming. On-demand has
got a story outside of IBM. But inside IBM, we are making it better with the
Power5 story.

Q: Power5+ is up next on the menu. What can you do in Power6 and
Power7 beyond what you’ve done in Power5, which seems to be a pole-vault
over the Power4?

What we did on Power4 was a technology-driven design. On 5, we did
technology but we also went outside the company. The model we have right now
is what I call “real-time design changes into a roadmap of chips.” We have a
Power5+ in a laboratory running to be announced next year. It’s like 200
square millimeters on a 90 nanometer design. It’s a beautiful story, and the
costs will be virtually nothing. But what’s more important than that is that
second pass of Power5+ is still open. We talk to customers, ISVs. We are
putting in design changes in real time before the gate shuts for it. If we
can’t get features in before the gate shuts for Power5+, we’ll get them in
Power6. If we can’t do that, we’ll do it in Power7.

We really have a
dynamic, real-time mechanism of listening outside and trying to squeeze it
in where it makes sense. There are some things I learned from the life
sciences community I couldn’t quite get into Power5 — they’ll get into
Power5+. We’re just in the infancy stage of a huge stepping stone of
engineering. Customers are becoming a part of our design team. They have a
huge influence. If I were to show you all of the 30 features we added, you’d
think each one in itself was trivial. That’s not the hard thing. The hard
thing was spending the time outside and creating the answer, which was

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