Does virtualization drive the future?
September 29, 2006
Does virtualization drive the future?. Check it out:(EDN Via Thomson Dialog NewsEdge) Over the 50 years since the first tabloid issue of
Electrical Design News
, underlying forces
have driven the evolution of the electronics industry. Since manufacturers
first fabricated transistors using photolithography, the inexorable shrinking
that process enabled has changed the world. Since it first became viable to put
a stored-program computer on a few chips, the shift of functions from hardware
to software has changed the world, as well.
These forces have been obviouswith obvious results. But consider
a more abstract and less obvious driving force that has, arguably, also been
important, and in the future may unleash a revolution as great as those of the
IC and microprocessor.
You could call that underlying trend "virtualization." The word is not
susceptible to a one-line definition, so let's digress for a moment. When you
use electrical quantities to perform physical work or release light, you say
the system is electrical. When you use the same quantitiescharge,
current, or voltageto convey information rather than merely to do work,
you say that the system is electronic. Virtualization is, in this sense, a step
beyond electronics. A systembe it a physical process, an object in the
real world, or an imaginary personis virtualized when it has undergone
three key steps. First, a boundary must isolate the system from its
environment. Second, designers identify the inputs and outputs that cross the
boundary, along with the transforms that produce the outputs, thus modeling the
system. Third, designers produce a functionally equivalent blockone
that accepts the same inputs and produces the same outputs under the same
circumstanceswith an electronic system.
From at least the mid-1960s, engineers have used electronic systems to
virtualize physical thingseither components of the electronic system
itself or objects in the outside worldand incorporate those models in
place of the real objects. This virtualization has made it possible for
electronic systems to behave as if they had hardware that they did not have. It
has also allowed systems to behave as if they were interacting with a world
from which they were isolatedeither by distance or by the fact that
that world didn't exist. These capabilities have accelerated the growth of
electronics and in the future are likely to lend electronic systems
capabilities that in the past were the province of humans alone.
In the beginningOne of the earliest exercises in virtualization waslike many a
breakthrough that later became standard practice in computer
architecturean advance in the IBM (
www.ibm.com
) 360 mainframe family. Before that
time, machine-code instructions in computers referenced memory through physical
addressesnumbers representing physical locations on the surface of a
drum or, after the development of magnetic cores, physical locations within the
array of small ferrite cores.
The development of virtual memory rested on the idea that the addresses
that machine instructions created needn't be the last word. If arithmetic
hardware were fast enough, it could translate addresses from the computer
program on the fly into physical addresses using some prearranged mapping. This
feature allowed a program that was assembled to run at one location in physical
memory to execute in another locationeven if the programmer had not
made all the memory references relative to the contents of a base register.
More important, it also meant that programs could run on a machine whose
physical memory was many times smaller than the virtual-address range the
program used. A portion of the operating systema well-developed concept
by this timecould allocate portions of the physical memory as necessary
for the immediate needs of the program, swapping blocks of information onto and
off of disk drives as necessary. By extension, this ability meant that a
modest-sized machine could concurrently run a number of large programs,
convincing each of them that it had access to all the physical memory it wanted
when in fact it was borrowing small blocks of memory on an as-needed basis.
Severing the link between the program's address spacewhich now became
virtualand the physical-address space was a huge and vital step in the
creation of modern data processing. But it was far from the last one.
At first glance, it might appear that this scenario has little to do
with the definition of "virtualization." However, the process executes all of
the steps in virtualization. IBM's designers isolated physical memory from the
rest of the mainframe system. They identified the inputsaddresses and
write dataand the outputstiming signals and read
datathat characterized the system. And they constructed a combination
of hardware, which would become a memory-management unit, and software, which
would become the virtual-memory manager that created a virtual main memory.
Virtualizing the IT worldRich Lechner, vice president of IBM Virtualization (
www-03.ibm.com/systems/ virtualization
), defines
the term as "the logical representation of resources not constrained by
physical devices." He points out that, when you use virtualization in this way,
it can "either treat one physical resource as if it were many or treat many,
possibly dissimilar, resources as if they were one." Lechner traces the
beginnings of virtualization to the 360 family's virtual-memory-system debut 40
years ago. But he says the practice has become far broader today than simply
virtualization of memory, which is now a common practice even in
microprocessors. "At one level, we can gather all of the storage assets
available to a network into a single pool of storage," Lechner says. In this
way, any program executing in the environment has access to all of the storage
assets of the network through a single interface.
But if you are not careful, you will face chaos. The location of stored
data does make a differencein access time, cost, persistence, and
coherence. So, for storage, virtualization has come to mean more than just
providing a mapping from a single mass-storage API (application-programming
interface) to a diverse set of storage devices. "The next level involves the
routine cleansing and deduplicating of the storage system," Lechner explains.
The virtualization system must make sure to remove stale copies of data,
propagate updates, eliminate duplicate data sets, and keep data in a place that
is most convenient to its clients. "This all by itself is a significant
benefit," Lechner says. "Our field studies indicated that, before
virtualization, the average midsized enterprise stores the same data in at
least 20 places around the network."
The process does not stop with storage systems. In just the same way,
system programmers can identify the computing resources in a network, give them
wrappers that present a common API, and hence virtualize them. In this way, the
computing power available to an application becomes a slice of the entire
computing community on the network, not simply the power of the machine on
which the application happens to be running.
The next step in this process is even a bit more abstract. You can
virtualize storage devices and servers, but what about applications? In exactly
the same way, system programmers can draw a wrapper around each application,
provide it with a set of APIs, and make it available to the network as a
virtual applicationsay, a virtual database. Thus, when an application
program executes in the network, it may be interacting with virtual-storage
devices on a number of storage networks, running on a virtual processor when
parts of the code are executing on a half-dozen servers around the network, and
calling virtual applications that may be data-bases from different vendors with
different organizations.
IT to embedded computingAll this virtualization might seem to be irrelevant to anything outside
the IT (information-technology) world. But if you think of a multicore embedded
systembased on the IBM Cell processor, for exampleas a
heterogeneous collection of computing resources, storage assets, and
interconnects, perhaps the relevance becomes more clear. As has so often been
the case, the IT solution of today is the SOC (system-on-chip) solution of
tomorrow. Virtualization may be the concept that makes SOCs with diverse
computing sites usable in real applications.
In fact, we are already seeing indications that this is the case. At
IMEC (Interuniversity Microelectronics Center,
www.imec.be
) in Leuven, Belgium, researchers
have created a virtual model of a runtime-configurable, multicore-computing
system for software-defined radio. Antoine Dejonghe, a principal scientist at
IMEC, describes the situation: "IMEC's M4 project is creating a radio system
that can be agile in real time across wireless protocols and media types," he
says. "We believe that technology scaling by itself won't be enough to bridge
the energy gap between what our configurable architecture requires and what
batteries will be able to provide. So, the viability of the system depends on
being able to model the entire system, from analog front end through the
media-access-controller software, in terms of its energy consumption. We will
use this model to establish the optimum trade-off between energy and quality of
user experience at runtimeperhaps as often as every 10 msec."
Today, the models are under constructionusing the same sequence
of stepsto create a virtual software-defined radio. Designers have
theoretically modeled the analog front end, for instance, with approximately 11
control bits as inputs, along with theoretically calculating output power,
distortion, and energy consumption. The designers are now calibrating these
models against actual silicon measurements. They will construct similar models
to predict the performance and energy consumption of the configurations of
IMEC's ADRES (architecture-for-dynamically
reconfigurable-embedded-system)-computing cores in the radio project.
The result will be a virtualization of the radio that should execute in
software, consuming less than 5% of an ARM9 and continually optimizing the
radio for current traffic, link quality, and application variables (Figure 1
). This process, Dejonghe believes, can bridge
the gap between what batteries can deliver and what battery life users will
demand.
Creating a virtual worldIMEC's work creates a virtualization of a physical system. However,
designers are virtualizing larger and more complex systems. Another easy place
to find excitement in virtualization is in the world of electronic games.
Traditionally, that virtualization did not exist. Most video games today have a
lot more in common structurally with a Walt Disney cartoon than with a
simulation of the physical world. Games, like cartoons, have story lines. The
choices of the player do not directly interact with the world of the game;
players merely choose story lines, and the game proceeds down one of the paths
the scriptwriters designed for it.
This scenario is true even at the macro level. When you slip around the
corner and level the four-eyed alien from the planet Grr
with your super halitosis blaster, you unleash a
sequence of animation frames, in which the Grrien satisfyingly rips open,
tumbles through the air, and lands as a puddle of unfamiliar proteins. This
sequence is almost the reverse of motion estimation in video-compression
algorithms: It begins with a set of key frames and animates incremental motions
of objects against a relatively fixed back ground. To the player, the result is
much the same no matter which way he triggers the sequence, unless he
misses.
As games become richer and players become more sophisticated, this
situation causes a problem, according to Manju Hegde, chief executive officer
and chairman of gaming "physics-engine" developer Ageia. He has a vested
interest in this problem because Ageia supplies software and hardware
accelerators for performing the dynamic computations necessary for eliminating
the animation sequences and computing the trajectories of the spinning Grrien
bits.
No oneleast of all, the animatorswould dispute that it
is better to do a dynamics-based simulation of the objects in the game world
than to rely on animation sequences. However, the greatest benefit would be to
the game architects. Because of the labor involved in producing animation
sequences from key frames, a game can have only a limited number of animation
sequences. So, architects must confine the action of the game so that only a
limited number of outcomes are possible at any time. The art of game design
today is to make the game feel rich and unscripted without causing an
exponential explosion in the number of key frames that developers must
prepare.
Hegde illustrates with a rather less violent example: a basketball game.
"If you want a realistic slam-dunk sequence in your game, you start out by
rigging lights all over your star player and then you record him doing some
dramatic dunks," Hegde explains. "Then, back in the lab, you extract from the
recording key frames and interpolate the movement of the image edges to produce
animation. This animation can look natural on the screen, but, any time you
push the slam-dunk button in the right context, you are going to see the same
sequence."
The alternative approach is to build a physics-based model of our
herothat is, to virtualize him. "We create a physics-based model of the
body," Hegde says. "Today, it can be as detailed as having approximately 200
bones connected by six kinds of joints. We then model each of these bones and
joints according to the laws of physics. You apply forces to them, and they
respond. Now, the dunk becomes the dynamics of the individual bones and joints
in the model person. If you view a game from a distance during fast action, a
game might use just 20 bones to reduce the calculations, but it looks 'right.'"
Hegde thus describes a scenario that fits this article's definition of
virtualizationin this case, of a basketball forward.
This virtualization has so many advantages over conventional animation
that manufacturers wouldexcept for a couple of issuesproduce
all games in this way. One of these issues goes back to scripting. If the
outcome of the player's input depends on both physics and the game script, the
sequence of play can quickly become unmanageable. What if physics dictates that
the player breaks his wrist on the rim of the basket and leaves the court
writhing in pain? Game architects who employ physics-based models often
intervene in the simulation to direct it to allowable outcomes, so that the
game stays within its script. This delicate business blends physical simulation
and animation.
A more brutal problem is the amount of computing requirements. "Today,
an AMD FX-62 dual-core CPU running at 2.8 GHz may be able to handle a couple of
characters with extensive bone models," Hegde says. "But you couldn't do
physics-based simulation with a large number of characters on the screen at
once. The bursts of computation necessary to support a number of characters all
running, for instance, would overwhelm the processors."
Microsoft's Robotics Studio (
www.microsoft.com/robotics
) is developing a
similar application, also using Ageia's technology. Rather than playing games,
the Microsoft group provides a virtual-development environment for the
programmingand, eventually, the designof robots. Tandy Trower,
general manager of the group, says that the need for such an environment is
obvious across the spectrumfrom industry to education. On one end, with
a KUKA (Keller und Knappich Augsburg) Robotics (
www.kuka.com
) robotic arm selling for more than
$100,000, industrial developers need a low-cost environment in which to develop
and test programs. At the other extreme, robotics has proved to be one of the
few endeavors that can attract US students to engineering and mathematics. Even
simple robots, however, are far beyond the reach of most secondary schools,
even though students have proved capable of programmingand even
designingthem. So an affordable virtualization of a robot and its
surroundings would be a big win, and Microsoft is attempting to achieve that
goal.
Building a virtual world behind the Direct-X graphics environment, the
company has provided libraries of models for popular robots; primitives for
constructing physical objects, machines, and other robots; and a physics-driven
simulation engine to animate them. "There are two ways of creating entities,"
Trower explains. "Developers can write them directly as codein C,
Visual Basic, Python, and the likethrough a managed code interface or
assemble them from basic geometric shapes and assign them physical
characteristics, such as mass, hardness, and so on" (Figure 2
). Once you set them in motion, the robots,
which are themselves entities, can interact with other entities, including
other robots, in a world that physical laws govern.
Trower points out that, although Microsoft's work in this area is on one
level similar to the physics-based modeling that is starting to appear in
games, it differs dramatically at another level. "Games take place in a
well-defined environment," he says. "Robot simulation does not. You have to
work out everything that happens based on physics, because there is no script."
Trower says that the virtualization technology could move from the development
tool into the robots themselves. For example, you can blend the simulation with
real-world sensor data. A robot that can include an optionaland
expensivelaser range finder, for example, might instead have a
virtualized range finder; fusing other sensor inputs to generate the range
data. In the future, you may see the next step: robots virtualizing the world
around them, a scenario that Brooke Williams, DSP-automotive-vision-marketing
manager at Texas Instruments (
www.ti.com
), sees before his own eyes.
"We are starting to see automobile-safety systems fusing sensor data to
create a virtual model of the car's surroundings," Williams says. "This model
can either be presented to the driver as warning information, or it can be used
to take control of the vehicle." For example, TI is combining radar, a good
tool for detection and ranging but poor for forming images, with machine-vision
systems, which are great at finding edges and bearings but poor at ranging or
detection. This combination of tools will allow the creation of virtual models
of the objects surrounding a car. "The object is to predict a crash; prepare
the vehicle by tightening seat belts, arming air bags, and closing the windows,
for instance; and attempting to take evasive action," Williams says.
But to achieve this goal, simple proximity warning is insufficient. The
tools must identify objects from their surroundings and track and categorize
them; the insurance industry must know that the system can distinguish between
pedestrians and shrubbery, for instance. You want to neither turn away in panic
from a car that can't physically reach your trajectory nor mow down a
pedestrian to avoid destroying a hedge. "Manufacturers are even talking about
external air bags that could deploy to protect pedestrians in collisions,"
Williams says. Such decisions require not just a measurement, but also an
understanding of the car's surroundings.
Therein lies a possible endpoint for the trend of virtualization:
electronic systems that can not only sense, but also model and predict their
environment. Such systems exhibit artificial intelligence and also express
virtualization. These systems, protecting drivers from their own folly,
exploring the otherwise-inaccessible reaches of the physical world, and using
their virtual models to reason about their surroundings, represent another
major expansion in the role of electronics.
You can reach Executive Editor Ron Wilson at 1-408-345-4427 and
[email protected].
Software I/O, virtual I/O, or software-assisted I/O?By David Fotland, Ubicom IncTypical microprocessor families have dedicated hardware for each I/O
function. This difference leads to families of chips with the same CPU but
different I/O mixes. Cost is higher because the semiconductor company must make
many chip versions, and mask costs are high in state-of-the-art process
technology. The alternative is to create an SOC (system on chip) with all of
the I/O hardware on the same chip. This approach also leads to higher cost,
because the customer is paying for silicon to implement I/O that he won't use
in his application.
The solution to this problem is software I/O. Some 8-bit
microcontrollers use this technique, called "bit-banged" I/O. If the
microcontroller has on-chip memory and deterministic execution, the software
can directly control I/O pins to implement the I/O protocol. A simple example
is a UART. The start bit causes an interrupt, and software reads the input pin
to receive the data. While the data is arriving, the CPU cannot do anything
else, so this technique is useful only for I/O that is infrequent or
intermittent. The interrupt-response time limits the use of this technique to
low-speed I/O.
Some 32-bit processors, such as those from ARM (
www.arm.com
) or MIPS (
www.mips.com
), can't use software I/O because
code execution is far from deterministic. Pipeline hazards and cache misses
make it impossible to use instructions for accurately timed external events.
Operating systems such as Linux turn off interrupts for milliseconds at a time,
making real-time I/O response impossible.
Ubicom (
www.ubicom.com
) has the only 32-bit CPU that
uses software I/O. The multithreaded CPU has a hardware scheduler that can
select a thread for execution during every clock. Real-time threads have a
fixed schedule and deterministic execution, even if other threads have
mispredicted branches or cache misses. The unit has 10 threads, so it can
allocate one real-time thread to each I/O port to manage that port.
The instruction set supports software I/O and packet processing. An
instruction can move data between memory and I/O. MIPS and ARM CPUs, in
comparison, need two instructions: a load and a store. Single instructions can
set, clear, or test any I/O bit. Interrupt-response time from an I/O event to
scheduling instructions in the managing thread takes only a few CPU clocks.
When an I/O port is idle, it suspends its managing thread, using no CPU
resources.
The high-performance, 32-bit CPU can use software-I/O for functions
more complex than a UART. Ubicom has implemented a full PCI bus at 27 MHz, MPEG
Transport Stream, IDE, and Utopia in software. It has also implemented MII
(media-independent interface) for 10/100-Mbps Ethernet, USB, SPI, GPSI
(graphics-processor software interface), and other serial interfaces with a
combination of hardware and software. By spending 10 to 20% of the CPU
throughput on software I/O, the company dramatically reduced the die area
necessary for I/O, resulting in a flexible single chip to cover a wide range of
applications.
Author's biographyDavid Fotland is chief technology officer of
Ubicom, where he led the architecture of the Ubicom multithreaded processor for
packet processing and software I/O. He is responsible for all aspects of
architecture and definition of processors and solutions.
Previously, Fotland spent 21 years at
Hewlett-Packard Co (
www.hp.com
) as lead engineer, project manager,
and system architect. He was a key participant in the PA-RISC instruction-set
definition and was lead designer of the first PA-RISC processor and system. He
was a leader in the development of the HP-Intel (
www.intel.com
) Itanium instruction
set.
Immersed in engineering, advanced 3-D visualization promotes
insightBy Jeff Brum, Fakespace SystemsAs electronics speed into an era in which manufacturers fabricate not
just circuits, but also physical structures themselves in nanoscale geometries,
the role of computer-based simulation as a design tool is increasingly
important. Correspondingly, the benefits of visualization in the review and
analysis of simulations play a growing role. Looking to the future, immersive
stereoscopic display tools will amplify the power of visualization.
The adoption of immersive visualization in electronics design revolves
around several factors. Atomic-scale phenomena, which are major concerns as the
semiconductor road map extends beyond the 65-nm-process node, have been major
players in advanced visualization techniques. Scientists at NIST (National
Institute for Standards and Technology,
www.nist.gov
), for example, use a stereoscopic
displaytwo walls and a floorto gain insight into the molecular
bonding of "smart-gel" polymers (Figure A and Reference A).
Similarly, researchers at LANL (Los Alamos National Laboratory,
www.lanl.gov
) use a range of immersive
environmentsfrom wall-sized to a 43-million-pixel, five-walled
projected roomto view terascale data sets (Figure. Bob Green,
visualization specialist at LANL, notes that the researchers "are viewing
simulations based on computations that generate more data than is contained in
the entire print collection of the Library of Congress in one calculation."
In engineering, visualization has had its largest impact to date in
macroscale CAD programs, such as automotive and aerospace design, and the
evaluation of complex structures for interferences that are not readily
apparent in simpler graphical representations. As simulation and visualization
data accumulate in MEMS (microelectromechanical-system) design, this type of
modeling and simulation will grow in importance. The ability to visualize and
"fly through" transistor-scale structures and even large segments of a complex
microcircuit design will also benefit from advanced 3-D visualization that
blends multiple streams of data, including device characteristics,
interconnects, and material behavior.
Wall- or even room-sized immersive displays support a more
collaborative, more intuitive, style of work than do graphics processors. A
major benefit in the review of complex structures is the ability to "move"
freely along all three axes of an image and still maintain the visual acuity of
high-resolution desktop processors. (Today's projectors support resolution of
14001050 pixels or higher.) Viewing nanoscale design can feel like
taking a helicopter tour over a dense city center with the ability to identify
and zoom into landmarks. Improved insight and collaboration lead to faster and
better decisions, speeding time to market and reducing development costs.
Although researchers are just beginning to measure the benefits of
immersive visualization (Reference
levels of insight to engineers and scientists. In immersive visualizations,
groups of users can view the inner workings of devices and gain deeper
understanding of electromagnetic effects and the relationships between elements
of a design. With the availability of dual PC clusters and advanced graphics
cards, these types of virtual environments no longer require specialized
graphics supercomputers. The increased accessibility of immersive visualization
makes its addition to the tool kit of electronic engineers practical and
inevitable.
References"Recipe for a Shake Gel," National Institute for Standards and
Technology, Aug 27, 2003,
www.nist.gov/public_affairs/newsfromnist_smartgels.htm
.
Kraak, Menno Jan, "Beyond Geovisualization,"
IEEE Computer Graphics and Applications
,
May/June 2006, Volume 26, No 3, pg 6.
Author's biographyJeff Brum is a vice president at Fakespace
Systems (www.fakespace.com), a division of Mechdyne Corp with a 15-year history
of developing and supporting advanced systems for immersive visualization in
science, engineering, and public-exhibition applications.
Copyright 2006 Reed Business Information. All Rights Reserved.
Related Tags: physical memory, physics based, electronic systems, animation sequences, immersive visualization, virtualization
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