Power Management

Vol. 5 No. 7 – November/December 2007

Power Management

Interviews

A Conversation with Mary Lou Jepsen

From Tunisia to Taiwan, Mary Lou Jepsen has circled the globe in her role as CTO of the OLPC (One Laptop Per Child) project. Founded by MIT Media Lab co-founder Nicholas Negroponte in 2005, OLPC builds inexpensive laptops designed for educating children in developing nations. Marvels of engineering, the machines have been designed to withstand some of the harshest climates and most power-starved regions on the planet.

A Conversation with Mary Lou Jepsen

What’s behind that funky green machine?

Photography by Liesl Clark

From Tunisia to Taiwan, Mary Lou Jepsen has circled the globe in her role as CTO of the OLPC (One Laptop Per Child) project. Founded by MIT Media Lab co-founder Nicholas Negroponte in 2005, OLPC builds inexpensive laptops designed for educating children in developing nations. Marvels of engineering, the machines have been designed to withstand some of the harshest climates and most power-starved regions on the planet.

To accomplish this, Jepsen and her team had to reinvent what a laptop could be. As Jepsen says, “You ask different questions and you get different answers.” The resulting machine, named the XO, is uniquely adapted to its purpose, combining super-low-power electronics, mesh networking, and a sunlight-readable screen, which Jepsen designed herself. Although still shy of the “$100 laptop” goal envisioned in the beginning, the XO is still the most inexpensive laptop ever built.

Articles

Big Games, Small Screens

One thing that becomes immediately apparent when creating and distributing mobile 3D games is that there are fundamental differences between the cellphone market and the more traditional games markets, such as consoles and handheld gaming devices. The most striking of these are the number of delivery platforms; the severe constraints of the devices, including small screens whose orientation can be changed; limited input controls; the need to deal with other tasks; the nonphysical delivery mechanism; and the variations in handset performance and input capability.

Big Games, Small Screens

Developing 3D games for mobile devices is full of challenges, but the rich, evolving toolset enables some stunning results.

MARK CALLOW, HI CORPORATION
PAUL BEARDOW, ECCOSPHERE
DAVID BRITTAIN, SUPERSCAPE

One thing that becomes immediately apparent when creating and distributing mobile 3D games is that there are fundamental differences between the cellphone market and the more traditional games markets, such as consoles and handheld gaming devices. The most striking of these are the number of delivery platforms; the severe constraints of the devices, including small screens whose orientation can be changed; limited input controls; the need to deal with other tasks; the nonphysical delivery mechanism; and the variations in handset performance and input capability.

Outside of the mobile market, developers had to target only two or three devices and deliver games on high-capacity media; in the mobile market they have to consider tens of devices per operator and package their games to fit in a compact download. The number and types of devices are also constantly changing; in a 12-month development cycle many new handsets can emerge. In addition, console development focus has been about length of play and numbers of levels, rather than the short bursts of intense activity that typify today’s mobile games. Furthermore, development time and budget are usually limited by low retail prices in the $5-10 range.

by Mark Callow, Paul Beardow, David Brittain

Document & Media Exploitation

A computer used by Al Qaeda ends up in the hands of a Wall Street Journal reporter. A laptop from Iran is discovered that contains details of that country's nuclear weapons program. Photographs and videos are downloaded from terrorist Web sites.

Document & Media Exploitation

The DOMEX challenge is to turn digital bits into actionable intelligence.

SIMSON L. GARFINKEL, PH.D.

A computer used by Al Qaeda ends up in the hands of a Wall Street Journal reporter. A laptop from Iran is discovered that contains details of that country’s nuclear weapons program. Photographs and videos are downloaded from terrorist Web sites.

As evidenced by these and countless other cases, digital documents and storage devices hold the key to many ongoing military and criminal investigations. The most straightforward approach to using these media and documents is to explore them with ordinary tools—open the word files with Microsoft Word, view the Web pages with Internet Explorer, and so on.

by Simson L. Garfinkel

Powering Down

Power management - from laptops to rooms full of servers - is a topic of interest to everyone. In the beginning there was the desktop computer. It ran at a fixed speed and consumed less power than the monitor it was plugged into. Where computers were portable, their sheer size and weight meant that you were more likely to be limited by physical strength than battery life. It was not a great time for power management.

Powering Down

Smart power management is all about doing more with the resources we have.

MATTHEW GARRETT, CONSULTANT

Power management—from laptops to rooms full of servers—is a topic of interest to everyone. In the beginning there was the desktop computer. It ran at a fixed speed and consumed less power than the monitor it was plugged into. Where computers were portable, their sheer size and weight meant that you were more likely to be limited by physical strength than battery life. It was not a great time for power management.

Now consider the present. Laptops have increased in speed by more than 5,000 times. Battery capacity, sadly, has not. With hardware becoming increasingly mobile, however, users are demanding that battery life start matching the way they work. People want to work from cafes. Long-haul flights are now perceived as the ideal opportunity to finish a presentation. Two hours of battery life just isn’t going to cut it; users are looking for upwards of eight hours. What’s drawing that power, and more importantly, how can we manage it better?

by Matthew Garrett

Kode Vicious

Take a Freaking Measurement!

Have you ever worked with someone who is a complete jerk about measuring everything?

Take a Freaking Measurement!

A koder with attitude, KV answers your questions. Miss Manners he ain’t.

Kode Vicious has been going strong for three years now, and thus far there has been no bottom to the well of coding-related questions, conflicts, and conundrums from which he draws. But to keep things fresh and interesting, we need your most pressing, current cries for help from out there in the coding trenches. Are you mystified by a never-before-addressed class of coding problem? Or have you seen an unwelcome shift in development methodologies? Chances are Kode Vicious is familiar with your plight. Drop him a line at kv@acmqueue.com.

Dear KV,

by George V. Neville-Neil

Opinion

Things I Learned in School

How many of us have not had the experience of sitting in a classroom wondering idly: "Is this really going to matter out in the real world?" It's curious, and in no small amount humbling, to realize how many of those nuggets of knowledge really do matter. One cropped up recently for me: the Finite State Machine (FSM). As we continue to develop the new UI for our product, we'll definitely be using FSMs wherever possible.

Things I Learned in School

As we continue to develop the new UI for our product, we'll definitely be using FSMs wherever possible.

Terry Coatta, Vitrium Systems

How many of us have not had the experience of sitting in a classroom wondering idly: "Is this really going to matter out in the real world?" It's curious, and in no small amount humbling, to realize how many of those nuggets of knowledge really do matter. One cropped up recently for me: the Finite State Machine (FSM).

To set the context for how the FSM changed my life -- well, at least made developing software easier for me -- I need to digress somewhat. The company that I work for is in the process of releasing a new version of its product. The previous version was entirely Web-based, but for the new version we wanted to increase the level of interactivity. We settled upon Flash as the infrastructure for building some of our UI.

by Terry Coatta

Articles

Understanding DRM

The explosive growth of the Internet and digital media has created both tremendous opportunities and new threats for content creators. Advances in digital technology offer new ways of marketing, disseminating, interacting with, and monetizing creative works, giving rise to expanding markets that did not exist just a few years ago. At the same time, however, the technologies have created major challenges for copyright holders seeking to control the distribution of their works and protect against piracy.

Understanding DRM

Recognizing the tradeoffs associated with different DRM systems can pave the way for a more flexible and capable DRM.

DAVID SOHN, CENTER FOR DEMOCRACY AND TECHNOLOGY

The explosive growth of the Internet and digital media has created both tremendous opportunities and new threats for content creators. Advances in digital technology offer new ways of marketing, disseminating, interacting with, and monetizing creative works, giving rise to expanding markets that did not exist just a few years ago. At the same time, however, the technologies have created major challenges for copyright holders seeking to control the distribution of their works and protect against piracy.

DRM (digital rights management)—broadly defined as technical measures used to protect content in digital media devices and services—is a response to these issues. Its role and impact in the digital media marketplace, however, are under debate. Proponents maintain that DRM can facilitate the secure distribution of digital content in new markets and help fuel new business models that exploit the power of digital media and the Internet, giving consumers many more choices. Critics, meanwhile, contend that DRM will do little to stop piracy and that its main effect may be to frustrate consumers’ ability to take advantage of the full power of digital media.

by David Sohn

Curmudgeon

Use It or Lose It

My 'aphorisme du jour' allows me to roam widely in many directions, some of which, I hope, will be timely and instructive for Queue readers.

Use It or Lose It

Aphorisms in the abstract

Stan Kelly-Bootle, Author

My aphorisme du jour allows me to roam widely in many directions, some of which, I hope, will be timely and instructive for Queue readers. My choice of the French aphorisme is a justifiably elitist affectation, paying homage to Montaigne, Voltaire, Bertrand Meyer, and that cohue d’elegance. The Gallic gargled r (as in Brassens) and the sublime long final syllable, if you get them right, simply drip with class compared with the slovenly sequence of English diphthongs: a-for-iz-um. (Anglophones also mangle the monosyllabic genre into john-ruh.) We tend to treat the terms aphorism and epigram as posh synonyms for maxim, motto, or even saying. They are all characterized by an attempt to condense volumes of wisdom into short, memorable phrases suitable, say, for adorning our college crests, tombstones, or car bumpers.

Originally, aphorism meant a definition, which is, in fact, quite the opposite of current usage. A definition, by nature, must spell out in detail (the definiens) exactly what the thing being defined (the definiendum) means. In modern parlance: zip(definiens) = definiendum; unzip(definiendum) = definiens. Unlike the compression of iTunes, quality is preserved! Once you’ve agreed on a definition, its use certainly helps in reducing the verbosity of future discourse. But, as Bertrand Russell remarked, definitions are simply optional shorthand tricks, saving space and time but not contributing anything essential to the theory. In practice, of course, as Russell admits, the very fact that we have singled out a compound entity worthy, as it were, of being defined can be significant in developing and explaining the theory. Thus, the definiendum momentum not only saves effort compared with “mass x velocity,” it also makes clear that that strange, unnatural product plays a key role in mechanics. Similarly with net pay, defined as “gross less deductions.”

by Stan Kelly-Bootle