Computing Now Exclusive Content — December 2009

News Archive

July 2012

Gig.U Project Aims for an Ultrafast US Internet

June 2012

Bringing Location and Navigation Technology Indoors

May 2012

Plans Under Way for Roaming between Cellular and Wi-Fi Networks

Encryption System Flaw Threatens Internet Security

April 2012

For Business Intelligence, the Trend Is Location, Location, Location

Corpus Linguistics Keep Up-to-Date with Language

March 2012

Are Tomorrow's Firewalls Finally Here Today?

February 2012

Spatial Humanities Brings History to Life

December 2011

Could Hackers Take Your Car for a Ride?

November 2011

What to Do about Supercookies?

October 2011

Lights, Camera, Virtual Moviemaking

September 2011

Revolutionizing Wall Street with News Analytics

August 2011

Growing Network-Encryption Use Puts Systems at Risk

New Project Could Promote Semantic Web

July 2011

FBI Employs New Botnet Eradication Tactics

Google and Twitter "Like" Social Indexing

June 2011

Computing Commodities Market in the Cloud

May 2011

Intel Chips Step up to 3D

Apple Programming Error Raises Privacy Concerns

Thunderbolt Promises Lightning Speed

April 2011

Industrial Control Systems Face More Security Challenges

Microsoft Effort Takes Down Massive Botnet

March 2011

IP Addresses Getting Security Upgrade

February 2011

Studios Agree on DRM Infrastructure

January 2011

New Web Protocol Promises to Reduce Browser Latency

To Be or NAT to Be?

December 2010

Intel Gets inside the Helmet

Tuning Body-to-Body Networks with RF Modeling

November 2010

New Wi-Fi Spec Simplifies Connectivity

Expanded Top-Level Domains Could Spur Internet Real Estate Boom

October 2010

New Weapon in War on Botnets

September 2010

Content-Centered Internet Architecture Gets a Boost

Gesturing Going Mainstream

August 2010

Is Context-Aware Computing Ready for the Limelight?

Flexible Routing in the Cloud

Signal Congestion Rejuvenates Interest in Cell Paging-Channel Protocol

July 2010

New Protocol Improves Interaction among Networked Devices and Applications

Security for Domain Name System Takes a Big Step Forward

The ROADM to Smarter Optical Networking

Distributed Cache Goes Mainstream

June 2010

New Application Protects Mobile-Phone Passwords

WiGig Alliance Reveals Ultrafast Wireless Specification

Cognitive Radio Adds Intelligence to Wireless Technology

May 2010

New Product Uses Light Connections in Blade Server

April 2010

Browser Fingerprints Threaten Privacy

New Animation Technique Uses Motion Frequencies to Shake Trees

March 2010

Researchers Take Promising Approach to Chemical Computing

Screen-Capture Programming: What You See is What You Script

Research Project Sends Data Wirelessly at High Speeds via Light

February 2010

Faster Testing for Complex Software Systems

IEEE 802.1Qbg/h to Simplify Data Center Virtual LAN Management

Distributed Data-Analysis Approach Gains Popularity

Twitter Tweak Helps Haiti Relief Effort

January 2010

2010 Rings in Some Y2K-like Problems

Infrastructure Sensors Improve Home Monitoring

Internet Search Takes a Semantic Turn

December 2009

Phase-Change Memory Technology Moves toward Mass Production

IBM Crowdsources Translation Software

Digital Ants Promise New Security Paradigm

November 2009

Program Uses Mobile Technology to Help with Crises

More Cores Keep Power Down

White-Space Networking Goes Live

Mobile Web 2.0 Experiences Growing Pains

October 2009

More Spectrum Sought for Body Sensor Networks

Optics for Universal I/O and Speed

High-Performance Computing Adds Virtualization to the Mix

ICANN Accountability Goes Multinational

RFID Tags Chat Their Way to Energy Efficiency

September 2009

Delay-Tolerant Networks in Your Pocket

Flash Cookies Stir Privacy Concerns

Addressing the Challenge of Cloud-Computing Interoperability

Ephemeralizing the Web

August 2009

Bluetooth Speeds Up

Grids Get Closer

DCN Gets Ready for Production

The Sims Meet Science

Sexy Space Threat Comes to Mobile Phones

July 2009

WiGig Alliance Makes Push for HD Specification

New Dilemnas, Same Principles:
Changing Landscape Requires IT Ethics to Go Mainstream

Synthetic DNS Stirs Controversy:
Why Breaking Is a Good Thing

New Approach Fights Microchip Piracy

Technique Makes Strong Encryption Easier to Use

New Adobe Flash Streams Internet Directly to TVs

June 2009

Aging Satellites Spark GPS Concerns

The Changing World of Outsourcing

North American CS Enrollment Rises for First Time in Seven Years

Materials Breakthrough Could Eliminate Bootups

April 2009

Trusted Computing Shapes Self-Encrypting Drives

March 2009

Google, Publishers to Try New Advertising Methods

Siftables Offer New Interaction Model for Serious Games

Hulu Boxed In by Media Conglomerates

February 2009

Chips on Verge of Reaching 32 nm Nodes

Hathaway to Lead Cybersecurity Review

A Match Made in Heaven: Gaming Enters the Cloud

January 2009

Government Support Could Spell Big Year for Open Source

25 Reasons For Better Programming

Web Guide Turns Playstation 3 Consoles into Supercomputing Cluster

Flagbearers for Technology: Contemporary Techniques Showcase US Artifact and European Treasures

December 2008

.Tel TLD Debuts As New Way to Network

Science Exchange

November 2008

The Future is Reconfigurable

Phase-Change Memory Technology Moves toward Mass Production

by George Lawton

Numonyx, a joint venture of chipmakers Intel and ST Microelectronics, says it has built a prototype of an advanced phase-change memory (PCM) chip that it hopes will become a breakthrough product in nonvolatile memory. The company reportedly demonstrated a 45 nm PCM chip with a 1 Gbit capacity, which will start mass production next year. Numonyx joined forces with Samsung Electronics earlier this year to begin mass production of a 512 Mbit chip. In June, the two companies announced the development of a common specification for phase-change chips, giving designers a common interface to work from.

Numonyx also announced R&D advances in the technology. Last year, it began research on a multilevel PCM that would let each chip cell store multiple bits. Last month, it announced two key advances that would support multilayer stacking of PCM material. Both technologies promise to increase PCM capacity once the technology has been refined for commercialization.

"We envisioned PCM as a potential successor to flash, but found that it had some unique new characteristics of its own," said Greg Atwood, a Numonyx senior research fellow who started working on the technology at Intel in 1999. Researchers expect PCM to be faster than flash memory and to consume less power than DRAM.

Understanding PCM

A 1970 Electronics magazine article coauthored by Gordon Moore described an early 128-bit PCM prototype at Intel. However, this tiny chip consumed too much power — 25 V at 200 mA (5 W) — and the technology was never widely used. Later, Stanford Ovshinsky, a research scientist who founded Ovonyx, made several ground-breaking technology advances that have since been licensed to all major PCM players. Today's PCM devices are energy efficient and on par with flash memory for speed.

The PCM chip is made of chalcogenide, a material that consists of at least one of the group-16 chemical elements in the periodic table, such as oxygen, sulfur, selenium, and tellurium. Light or heat can easily switch this material between a polycrystalline and amorphous state, which also changes its optical and electrical resistivity properties.

In a PCM chip, individual bits are heated up, then written to by using electrical current and read by measuring each bit's resistance. Rewritable CDs apply the same principle, using a high-powered laser to change a cell's state and a lower-powered laser to read its state.

Where PCM Fits

PCM is nonvolatile like flash memory, so it requires no power when it's not being read or written to. It can be read and written to nonsequentially, like DRAM and NOR flash, which makes it ideal for storing and running code. In contrast, the more cost effective and widely used NAND flash can be read only in long sequences and written to only a page at a time, limiting its utility to reading and writing whole files. According to Atwood, PCM has a data-seek time on the order of 100 nanoseconds versus microseconds or milliseconds for flash.

PCM can be read at the same fast rate as DRAM. Writes are considerably slower than DRAM but on par with flash memory. Atwood said that today's PCM can write at 10 Mbytes per second compared with several hundred megabytes per second for DRAM.

PCM has an average life cycle of 1 million writes and could go higher, which is much higher than flash at 100,000 writes but lower than DRAM, which is infinite. This limit could pose a problem if flash was used as the primary storage in a memory-intensive application, such as an enterprise server.

However, Atwood believes that PCM might be ideal as a secondary memory in such applications, helping reduce the size and hence the power requirements of DRAM. Unlike PCM and other nonvolatile memories, DRAM must be fully powered at all times.

Increasing PCM Capacity

Numonyx is researching two techniques to increase memory capacity. One would increase the number of bits stored in each cell; the other, the number of layers used to store data. Both technologies are in a preliminary stage and are not expected to be used commercially for several years.

The technique to store multiple bits in each cell actually stores data in analog elements. The element's state is converted into digital data by measuring the chalcogenide material's resistivity. The technique uses an increase in measurement precision to differentiate between more bits in each cell, but it's costly and can raise the error rate. Flash memory has employed a similar technique, but it's a more mature technology.
The other R&D advance uses a chalcogenide material made from germanium, antimony, and tellurium, which can be stacked between specially crafted metal layers. This technique involves a new device called an ovonic threshold switch, which replaces the bipolar transistor traditionally used in PCM and allows the device to address multiple layers. Numonyx has so far demonstrated only the first layer of this new design, but Atwood said the first layer is the hardest. Additional layers can use standard process technologies. Although there's no theoretical limit to the number of layers that can be stacked, Atwood said that the company is likely to create only four-layer chips in practice because each layer can potentially introduce defects and hence reduce the yield of working chips.

Challenges and Applications

The biggest challenge PCM faces is cost, said Jim Handy, a memory-industry analyst with Objective Analysis. The first-generation PCM chips are considerably more expensive owing to reduced economies of scale and substantially less R&D than traditional silicon-based technologies such as DRAM and flash memory. "We have over $200 billion of R&D as an industry in understanding silicon compared with on the order of $200 million on PCM," said Handy.

In the near term, designers will employ conventional PCM designs from Samsung and Numonyx, said Stephen Hudgins, technical consultant to Ovonyx, which licenses PCM technology to both companies. PCM will have a hard time competing with NAND flash for many applications because of the higher cost, but it will become more competitive as memory devices scale. Flash memory is fundamentally limited by the challenges associated with storing electrons in smaller memory elements. PCM doesn’t face these challenges because it doesn't store electrons. It can therefore scale down to smaller sizes and higher densities. 'Ultimately, economics will dictate against NAND flash," Hudgins said.

Hudgins expects PCM to replace NOR flash memory and possibly DRAM for code storage in portable devices. Replacing DRAM could provide substantial power savings and longer battery life.

George Lawton is a freelance technology writer based in Monte Rio, California. Contact him at