Category: Geek stuff

If it involves physics, math, computer science, electronics or has general geek cachet, this is the place for it.

Making the best of overlapping WiFi

Most of the places I have lived during the last few years have been permeated by more than ten overlapping WiFi networks. Apartments and businesses each have their own internet connection which they connect to their own devices via a wireless router.

Unfortunately, the effect of so many simultaneously operating networks can be one of disruptive interference between them. Everyone gets slower and patchier internet access as all the routers compete for the relatively small number of communication channels that are part of the WiFi standard.

It would be really neat if people could develop software to allow routers to engage with each other intelligently. Consumers could program in their preferences regarding total bandwidth usage, whether to let strangers use their network, and so on. The routers could then make intelligent use of the infrastructure that is available: turning off less capable WiFi hotspots to reduce interference, directing traffic through the connections of those with large bandwidth caps, and deploying encryption technology to foil some of the illegal surveillance that has become commonplace around the world. There could even be a quid pro quo system implemented; people who are willing to share their internet connection with strangers could be granted priority access by the routers of others. By sharing my home internet connection in Toronto, for instance, I might be given a login credential that I could use with appropriate routers in other cities. With a big enough network of users, such connection sharing could be very useful.

This isn’t a system that would need to be deployed all at once by all router manufacturers. A few could adopt a voluntary standard for cooperation between routers. That would allow for some real-world testing and the identification of any problems related to functionality or security. In the end, the result could be the bottom-up development of a more effective and secure mechanism for wireless internet access in high-density environments.

Three days in Montreal

My father and I will be in Montreal until Saturday, visiting my brother Sasha.

On the way up from Toronto, we stopped at the Darlington Nuclear Generating Station. Unfortunately, there are no tours of the main complex. We were able to wander around the general area, as well as visit an information centre.

I put some photos on Flickr. Later, I got some of a ‘casserole’ protest in Montreal, near Rue St. Denis.

Illuminated timepiece and memento mori

After five years in The Service That Must Not Be Named – and with just a few days left before I leave to resume my studies – I got myself the Marathon Watch Company’s imaginatively-named General Purpose Quartz w/ Date, Type I, Class 1 watch as a kind of retirement gift to self.

The major distinguishing characteristic of the watch is the way in which it uses tritium-filled tubes for illumination. At each hour marker, as well as on the hour and minute hand, there are tiny tubes of phosphor-coated borosilicate glass containing a minute volume of radioactive tritium. This allows it to be easily read in conditions of total darkness. The tritium atoms are constantly undergoing beta decay and turning into helium-3. This process produces an electron with about 5.7 keV of energy and an electron anti-neutrino. The electrons hit the phosphors, causing the glow. The watch glows with radioactive fire, using the transmutation of hydrogen into helium for energy. It also produces antimatter that zips easily through the planet.

While I hadn’t intended it this way, the strongest impression from wearing the watch is that it is a memento mori – a token that reminds a person of their inevitable death. There are a few reasons for this. Most obviously, the tritium decay occurs with a half-life of about 12.32 years. Every time that span passes, the glow becomes half as bright. Ordinarily, watches highlight the circularity of time; we wake and sleep at similar times most days, pay our bills at the end of the month, and so on. The decay of the tritium is a reminder that time runs in only one direction, and there is no undoing what is in the past.

Tritium itself also has some rather ominous associations. For one thing, the gas in the watch was probably made in a nuclear reactor through the irradiation of lithium. For another, tritium is an integral component in modern nuclear weapons: both in the core of ‘boosted’ fission weapons and in the secondary stage of Teller-Ulam configuration thermonuclear weapons. On a more practical level, if the tritium leaks out from the glass tubes and forms tritiated water, it probably wouldn’t be especially good for a person to ingest.

I am pleased with the unexpected thoughts brought on by the watch. Too often, I think, we ignore the reality of our mortality and the urgency of the present moment. It’s easy for life to become routine and automated, with relatively trivial tasks occupying our time alongside relatively trivial thoughts. Being frequently reminded about the unidirectional nature of time – and about some of the terrors of the world – seems to force us to concentrate on what we want to do before we fade and expire.

Dark times

Bill McKibben on the state of the climate change mitigation movement:

“Since I wrote one of the first books for a general audience about global warming way back in 1989, and since I’ve spent the intervening decades working ineffectively to slow that warming, I can say with some confidence that we’re losing the fight, badly and quickly – losing it because, most of all, we remain in denial about the peril that human civilization is in.”

It’s pretty worrisome that some of the most articulate and convincing voices calling for action on climate change are now despairing about humanity’s ability to get things under control.

McKibben’s article talks about how risky warming the planet by even 2°C would be, going on to point out that we are on track to push temperatures up by more like 6°C by 2100. If we want to stay below 2°C, we can only burn about 1/5 of the world’s proven reserves of oil, gas, and coal. Those reserves are worth about $27 trillion, which explains why fossil fuel companies are so desperate to prevent effective action on climate change.

The fossil fuel companies and the politicians that support them are winning the fight over what kind of world will exist in the future, and humanity did more in 2011 to make the problem worse than in any previous year.

Periodic Tales

Hugh Aldersey-Williams‘ book Periodic Tales: The Curious Lives of the Elements shows off the author’s wide range of knowledge, willingness to investigate, and ability to tell a compelling story. Starting with gold and finishing with a pilgrimage in search of rare earth metals, Aldersey-Williams covers a fair fraction of the periodic tale – identifying the importance of elements not only in chemistry, but in diverse fields including art, literature, and theology. There are also many nice little nuggets of information, such as how Inuit steel tools were made from the nickel-containing natural stainless steel in some meteorites.

In addition to tracking down physical specimens of elements, the author tries to extract some on his own using natural materials said to be abundant sources (urine for phosphorus, kelp for iodine, even testing whether rotting herring luminesces). This admirable curiosity and willingness to undertake experiments adds much to the book.

Despite being about 400 pages, the book is a very quick read. It is well worth a look for anybody who is curious about the building blocks of the world or, alternatively, who is interested in seeing how the process of scientific discovery interacts with other human undertakings.

Thermus aquaticus and Taq DNA polymerase

Interesting fact: the hotsprings of Yellowstone Park yielded an enzyme that is critical for the DNA-copying polymerase chain reaction (PCR):

“In the hot springs of Yellowstone National Park, [American microbiologist Thomas] Brock (then 40, now 85) had discovered a microbe which he christened Thermus aquaticus, a creature that could survive at temperatures as high as 80°C. At once, our sense of the life-sustaining zone on Earth expanded. “It was Brock who set the ball rolling,” says Michael Danson. “What has happened since is that the temperature has been set higher and higher. The highest temperature record at which growth has been observed is 121°C.”

Thermus aquaticus was also, serendipitously, the organism that established the enormous potential practical importance of these newly discovered life forms. The point about a thermophilic bacterium is that it needs some very tough enzymes, the catalysts of living processes. Our own enzymes break down very quickly at high temperatures, which is another reason that life outside what we consider a normal temperature range was thought impossible. An enzyme in Thermus aquaticus is now known as Taq DNA polymerase and it has become one of the most important enzymes in microbiology. It made possible the polymerase chain-reaction (PCR) technique for amplifying DNA samples. This led to the uses of DNA in forensic science and, in fact, to much of what we now know about DNA. PCR is a molecular photocopier, making it possible to take very small samples of DNA and repeatedly reproduce them. So now murderers have to be obsessively clean if they are to escape the attentions of the forensic scientist.

On a high school field trip, I once got to replicate my own DNA using PCR, at a lab in the University of British Columbia.

Web servers are vulnerable machines

Imagine you have rigged up an unusual machine, like a home-made steam engine or a centrifuge. Even if it seemed to be working smoothly, it’s not the sort of thing you would want to leave unattended. It’s quite likely that doing so would break the machine, and quite probably cause damage to nearby property or people.

It’s important to remember that a web server is a pretty sophisticated machine. An entry served up by a WordPress blog is quite a different thing from a printed newspaper article or even a static HTML page. When you view a WordPress page, there is a dynamic interplay between your web browser and the web server. You request particular content and WordPress uses PHP scripts to pull together the necessary data from MySQL databases. The same is true for other dynamic content management systems (CMS), like Joomla or MediaWiki. Underneath all this, there is Apache HTTP Server and whatever operating system the server is running.

All this PHP and MySQL work creates openings for attackers. These can never be completely eliminated, though maintaining an updated version of your CMS and being careful about things like passwords and file permissions is important.

What may be most important, I think, is changing the perception of what kind of machine a web server is. You cannot assume that it will continue to obediently do what you want if you leave it alone. It is quite possible that some malicious human or robot will find a crack, take control of it in whole or in part, and then use it for nefarious tasks like sending spam or joining a botnet. If you aren’t paying any attention to things like your server logs, you might never even know that your site has been compromised.

In short:

  1. If you run a webserver, be aware that it is a constant target for attack.
  2. It is wise to take precautions, like promptly updating software and choosing strong passwords.
  3. Keep an eye open for unauthorized activity.
  4. Have backups in place for recovery after an attack.

Practice safer blogging!

Gorbachev on the end of the Cold War

Following up on his exceptional books The Making of the Atomic Bomb and Dark Sun, historian Richard Rhodes‘ The Twilight of the Bombs provides fascinating details on all matters nuclear-weapon-related during the fall of the Soviet Union and years afterward. For instance, there are many details on the clandestine Iraqi nuclear weapons program in operation after the first Gulf War, along with frightening details on the August coup against Mikhail Gorbachev and the protection of American tactical nuclear weapons in Europe during the later years of the Cold War.

One interesting passage Rhodes quotes comes from Gorbachev’s speech from Christmas Day, 1991 formally dissolving the Soviet Union:

“We had plenty of everything: land, oil, gas and other natural resources, and God had also endowed us with intellect and talent – yet we lived much worse than people in other industrialized countries and the gap was constantly widening. The reason was apparent even then – our society was stifled in the grip of a bureaucratic command system. Doomed to serve ideology and bear the heavy burden of the arms race, it was strained to the utmost… The country was losing hope. We could not go on living like this. We had to change everything radically.”

Rhodes, Richard. The Twilight of the Bombs: Recent Challenges, New Dangers, and the Prospects for a World Without Nuclear Weapons. p.116 (hardcover)

In another fascinating passage, Rhodes discusses the control systems in place for the Soviet nuclear arsenal during the August coup. With the particular combination of conspirators involved, it was not possible for them to make unauthorized use of the Soviet strategic nuclear arsenal. A different group of conspirators with different tactics and objectives, however, might have been able to circumvent the Soviet nuclear controls and use weapons without Gorbachev’s approval:

“‘There is an important lesson here,’ [Bruce] Blair concluded. ‘No system of safeguards can reliably guard against misbehaviour at the very apex of government, in any government. There is no adequate answer to the question, “Who guards the guards?”‘”

Ibid. p.95