February 25, 2020

Archives for June 2006

Freeing the Xbox

When Microsoft shipped its Xbox game console, Linux programmers salivated. The Xbox was a pretty nice computer, priced at $149. The Xbox had all the hardware needed to run Linux and its applications. Problem was, Microsoft had tried to lock down the Xbox hardware to prevent unauthorized programs – such as the Linux kernel – from running on it. An article at xbox-linux.org explains how this lockdown plan failed. The technical details are quite interesting, but nontechies can learn from this story too.

Microsoft had two reasons for locking down the hardware. It wanted to stop people from running Xbox games that had been illegally copied. And it wanted to stop people from running other (noninfringing) software such as Linux. The latter goal is the more interesting one. Microsoft did this because it wanted to sell the Xbox hardware at a loss, and make up the difference by charging a premium for games. To do this, it needed to stop unauthorized software – otherwise people might buy the Xbox, install another operating system on it, and never buy an Xbox game.

A group of clever engineers, calling themselves the Xbox Linux Project, set out to discover how Microsoft had tried to lock down the Xbox hardware, and how they could overcome Microsoft’s lockdown and install Linux. We would expect them to succeed – in computer security, physical control of a device almost always can be leveraged to control the device’s behavior – and indeed they did. The bulk of the Xbox-Linux article describes the technical details of how Microsoft’s lockdown worked, how they reverse engineered it, and the tricks they discovered for capturing effective control of the Xbox and installing Linux on it.

Opponents of this kind of tinkering often argue that it is really just a front for copyright infringement – that the tinkerers really just want to run illegally copied games. But the article describes a group of people who just want to run Linux on their Xboxes, and are willing to take steps to stop their work being misappropriated by game copiers. For example, the article says that once they had figured out a trick, which the article calls a “hack”, for installing new software on the Xbox, they tried to use it responsibly:

But the Xbox Linux Project did not blindly release this hack. The first … proof of concept exploit had been finished in January 2003. After that, a lot of energy was invested in finding out a way to free the Xbox for homebrew development and Linux, but not allowing game copies. Microsoft was contacted, but without any success. They just ignored the problem.

Finally in July, the hack was released, with heavy obfuscation, and lockout code for non-Linux use. It was obvious that this would only slow down the “hacking of the hack”, so eventually, people would be able to use this vulnerability for copied games, but since Microsoft showed no interest in finding a solution, there was no other option than full disclosure. The suggestion of the Xbox Linux Project would have been to work together with Microsoft to silently close the security holes and, in return, work on a method to let homebrew and Linux run on the Xbox.

What should public policy have to say about this? Given that the Xbox Linux folks apparently weren’t trying to copy games but simply wanted to run noninfringing software on lawfully purchased hardware, and given that they took steps to hinder the use of their work for infringing purposes, it’s hard to object to their work on copyright grounds. The real action here is in Microsoft’s strategy of selling the Xbox hardware as a loss leader, and the tendency of the Xbox Linux work to frustrate this strategy. Xbox Linux creates value for its users. Should public policy be willing to destroy this value in order to enable Microsoft’s pricing strategy? My instinct is that it should not, though there is a plausible argument on the other side.

What is clear, though, is that this is not really a copyright issue. At bottom, it’s not about the right of Microsoft to be paid for the Xboxes it builds, or about the right of game authors to be paid for the copies of their games that users get. Instead, it’s about whether Microsoft can control how people use its products. In general, the law does not give the maker of a product the right to control its use. Why should the Xbox be any different?

How I Spent My Summer Vacation

Ah, summer, when a man’s thoughts turn to … ski jumping?

On Sunday I had the chance to try ski jumping, at the Swiss national team’s training center at Einsiedeln. My companions and I – or at least the ones foolish enough to try, which of course included me – donned thick neoprene bodysuits, gloves, helmets, and ski boots. We clumped up a short path then strapped on our skis and set off down the jumping track. Having skied only twice before – and that twenty-five years ago – I found this a real adventure, about which more below.

Ski jumping, it turns out, is a popular summer sport, probably more popular in the summer than the winter. I can understand why the spectators would prefer summer weather, but the jumpers’ gear felt better suited for winter than for the 25-degree Centigrade (80-degree Fahrenheit) day we had. The bodysuits are so hot, in fact, that every male jumper, whether expert or rookie, unzipped his suit and peeled it back to the waist when not jumping, exposing a tanned muscular torso, in some cases.

Skiing in summer requires a special surface. On the jumping ramp, the skis ride in two parallel tracks made of a ceramic material speckled with pea-sized bumps sticking upward so that the skis touch only the bumps. The landing area is thatched with countless thin, green plastic sticks about 20 cm (eight inches) long, anchored on one end with the other end pointing downhill. These are hosed down with water to reduce friction. At the bottom of the hill is a stopping area covered with wood chips.

After our own attempts at jumping (be patient; I’ll tell all below), we watched some expert Swiss jumpers practicing, from several vantage points. (YouTube video) From the top where the jumpers start, the ramp seems impossibly steep and stretches far below. It must take considerable courage to look down the ramp and then let oneself go. As the coach told us, once you start, there’s no turning back – you’re going to end up at the bottom of the hill one way or another. You have to be fearless. Unsurprisingly, the jumpers we saw all looked like seventeen-year-old young men.

Though the jumpers go fast, they never get very high above the ground. At the jump point, the ramp is 1.5 meters (five feet) above the ground. Below the jump point, the hillside curves down parabolically, parallel to the flight path that a jumper would follow in the absence of air resistance. So a jumper who doesn’t spring upward is never more than 1.5 meters off the ground. A skilled jumper might reach three meters (ten feet) above the ground. But then again he’ll be going very fast and will fly more than 100 meters (330 feet) down the hill.

The best view is from the takeoff point. You see the jumper start, far above. As he accelerates down the ramp toward you, his body locked in a compact crouch, you hear a ferocious clattering as his skis drum over the bumps in the ceramic tracks. Suddenly the ramp vanishes beneath him as he springs upward. At that moment he flashes past you, and the clattering is replaced all at once with an insistent whooshing, hissing sound as the jumper floats down the hill, his ski tips spread, his body leaning forward like a more aerodynamic Superman. In a second he vanishes behind the downward curve of the hill, and you wait for the faint but firm slapping noise of a safe landing. He returns to view at the base of the hill as he coasts to a stop on a flat grassy area. Nonchalantly, he removes his helmet, gloves, and skis, and half-unzips his body suit, as the next jumper begins.

The jump used by our group of rookies was maybe one-tenth the size of the big jump. Still, it looked distressingly long and steep from the top. On our first trip down the hill, we started just below the jump point, to practice skiing down the landing ramp. The trick is to maintain your balance on the strange green-stick surface as the hill curves sharply downward and then levels out again. Without ski poles, and with your ankles held rigid by the ski boots, you have little leverage to shift your weight forward or backward. Side to side balance is easy, but that’s not the problem.

As I awaited my first run, one of my companions jokingly (in German) asked the onsite medical expert how far it was to the hospital. Not to worry, she answered, the hospital was practically at the bottom of the hill. With that reassurance, I levered my skis out onto the top of the landing ramp and faced down the hill, as the coach held me motionless.

And then I was moving jerkily downhill as my skis fought the initial friction of the green sticks. I recovered my balance and picked up speed as the hill reached what seemed like a 45-degree angle. For a moment I tried to remember whether skiing on snow felt like this, but the thought was thrust aside by a rush of adrenaline and the sense that I was starting to lose my balance. As I reached the bottom of the hill any illusion of balance was gone, and I tumbled to a stop on the wood chips. I lay on my side, my skis angled awkwardly behind me, still attached to my feet. But I was unhurt and decided to try again.

On my second run, things went awry almost immediately. As I started I sensed that I was leaning ever so slightly backward. The downward curve of the hill started to tilt me backward even more. I struggled to get my center of gravity over my feet but it was hopeless. I ended up laying myself down on one hip and sliding comfortably down the last part of the hill. I was none the worse for wear, but my bodysuit was drenched from sliding over recently-watered green sticks.

I felt fine but decided not to try again. Two falls is enough for a guy of my age. I cheered on my companions as some of them managed to make short jumps and reach the bottom of the hill gracefully. Then we headed off for a delightful lunch and a tour of the Einsiedeln monastery and a stunningly restored church crowded, for some reason, with thousands of visiting Sri Lankans.

Having learned firsthand how hard ski jumping is, I was even more amazed to see the skilled jumpers casually launch themselves off the big jump. Next Winter Olympics, ski jumping will be a must-watch.

(My companions are invited to identify themselves and/or tell their own stories, in the comments.)

Syndromic Surveillance: 21st Century Data Harvesting

[This article was written by a pseudonymous reader who calls him/herself Enigma Foundry. I’m publishing it here because I think other readers would find it interesting. – Ed Felten]

The recent posts about 21st Century Wiretapping described a government program which captured, stored, filtered and analyzed large quantities of information, information which the government had not previously had access to without special court permission. On reading these posts, it had struck me that there were other government programs that are in the process of being implemented that will also capture, store, filter and analyze large quantities of information that had not been previously available to governmental authorities.

In contrast to the NSA wiretap program described in previous posts, the program I am going to describe has not yet generated any significant amount of public controversy, although its development has taken place in nearly full public view for the past decade. Also, unlike the NSA program, this program is still hypothetical, although a pilot project is underway.

The systems that have been used to detect disease outbreaks to date primarily rely on the recognition and reporting of health statistics that fit recognized disease patterns. (See, e.g., the summary for the CDC’s Morbidity and Mortality weekly Report.) These disease surveillance systems works well enough for outbreaks of recognized and ‘reportable’ diseases which, by virtue of having a long clinically described history, have distinct and well-known symptoms and, in almost all cases, definitive tests exist for their diagnosis. But what if an emerging infectious disease or a bio-terrorist attack used an agent that did not fit a recognized pattern, and therefore there existed no well-defined set of symptoms, let alone a clinically meaningful test for identifying it?

If the initial symptoms are severe enough, as in the case of S.A.R.S., the disease will quickly come to light. (Although it is important to note that that did not happen in China, where the press was tightly controlled) If the initial symptoms are not severe, however, the recognition that an attack has even occurred may be delayed many months (or using certain types of agents, conceivably even years) after the event had occurred. To give Health Authorities the ability to see events that are outside the set of diseases that are required to be reported, the creation of a large database, which would collate information such as: workplace and school absenteeism, prescription and OTC (over the counter) medicine sales, symptoms reported at schools, numbers of doctor and Emergency Department visits, even weather patterns and veterinary conditions reported could serve a very useful function in identifying a disease outbreak, and bringing it to the attention of Public Health Authorities. Such a data monitoring system has been given the name ‘Syndromic Surveillance,’ to separate it from the traditional ‘Disease Surveillance’ programs.

You don’t need to invoke the specter of bioterrorism to make a strong case for the value of such a system. The example frequently cited is a 1993 outbreak in Milwaukee of cryptosporidium (an intestinal parasite) which eventually affected over 400,000 people. In that case, sales of anti-diarrhea medicines spiked some three weeks before officials became aware of the outbreak. If the sales of OTC medications had been monitored, perhaps officials could have been alerted to the outbreak earlier.

Note that this system, as currently proposed does not necessarily create or require records that can be tied to particular individuals, although certain data about each individual such as place of work and residence, occupation, recent travel are all of interest. The data would probably tie individual reports to census tract, or perhaps census block. So the concerns about individual privacy being violated seem to be less then in the case of the NSA data mining of telephone records, since the information is not tied to an individual and the type of information is very different from that harvested by the NSA program.

There are three interesting problems created by the database used by a Syndromic Surveillance system: (1) The problem of False Positives, (2) Issues relating to access to and control of the data base & (3) What to do if the Syndromic Surveillance system actually works.

First with regard to the false positives, even a very minor rate error rate can lead to many false alarms, and the consequences of a false alarm are much greater than in the case of the NSA data filtering program:

For instance, thousands of syndromic surveillance systems soon will be running simultaneously in cities and counties throughout the United States. Each might analyze data from 10 or more data series—symptom categories, separate hospitals, OTC sales, and so on. Imagine if every county in the United States had in place a single syndromic surveillance system with a 0.1 percent false-positive rate; that is, the alarm goes off inappropriately only once in a thousand days. Because there are about 3,000 counties in the United States, on average three counties a day would have a false-positive alarm. The costs of excessive false alarms are both monetary, in terms of resources needed to respond to phantom events, and operational, because too many false events desensitize responders to real events….

There are obviously many issues relating to public policy regarding to access and dissemination of information generated by such a public health database, but there are two particular items providing contradictory information which I’d like to present, and hear your reactions and thoughts:

Livingston, NJ -When news of former President Bill Clinton’s experience with chest pains and his impending cardiac bypass surgery hit the streets, hospital emergency departments and urgent care centers in the Northeast reportedly had an increase in cardiac patients. Referred to as “the Bill Clinton Effect,” the talked-about increase in cardiac patients seeking care has now been substantiated by Emergency Medical Associates’ (EMA) bio-surveillance system.

Reports of Clinton’s health woes were first reported on September 3rd, with newspaper accounts appearing nationally in September 4th editions. On September 6th, EMA’s bio-surveillance noted an 11% increase in emergency department visits with patients complaining of chest pain (over the historical average for that date), followed by a 76% increase in chest pain visits on September 7th, and a 53% increase in chest pain visits on September 8th.

The second story has to do with my own personal experience and observation of the Public Health authorities’ actions in Warsaw immediately following the Chernobyl accident. In Warsaw, the authorities had prepared for the event, and children were immediately given iodine to prevent the uptake of radioactive iodine. This has been widely credited with preventing many deaths due to cancer. In Warsaw, the Public Health Authorities also very promptly informed the public about the level of ambient radiation. Certainly, there was great concern among the populace but panic was largely averted. My empirical evidence is of course limited, but my gut feeling is that much dislocation was averted by (1) the obvious signs of organized preparation for such an event, and (2) the transparency with which data concerning public health were disseminated.

article summarizing ‘Syndromic Surveillance’
CDC article
epi-x, CDC’s epidemic monitoring program