Saturday, August 27, 2005

Why irrevelant text adverts keep appearing on tech sites

I'm sure that there's more than one reason for it, but Tim O'Reilly's recent article provides some insight into one cause.

Search engine spammers (or optimisers; is this the hacker/cracker thing again?) have trouble getting high page ranks through link farming (because Google now ignores link farms) and find the prices for certain AdSense keywords (to appear as sponsored links in Google's search results) too high, so instead they pay high page-ranked sites to carry their text ads to get some reflected page rank. That is to say, the people viewing the pages that these ads appear on are not in fact the intended audience; rather people searching Google for particular keywords are the intended audience, this is merely a means to get Google to put them there, and for the high page-ranked site to make some cash on its "position".

I don't yet have an opinion on the validity or otherwise of this practice, but discovering why something odd happens is often of interest.

(via Kottke)

Power transmission line corridors as wildlife sanctuaries

Are (U.S.) power distribution companies about to find a way to re-spin their allegedly-cancer-causing transmission lines as wildlife sanctuaries? Apparently some companies have recently switched from using non-selective herbicides in these corridors (to stop large shrubs and trees growing to the point where they damage equipment) to using more selective ones and simply removing tall vegetation after it's appeared, but before it threatens equipment. An astonishing affect on bee populations has been observed:
The statistics showed that the bees collected in the power line scrubs were more diverse than those in the grassy fields
...
The power line scrubs tended to have rarer species and more bee-parasite species, which is normally an indication of a healthy bee community, she says.
Bees may seem like a pretty small part of Earth's ecosystem (and they are), but there are more than 20,000 species of them and, of course, they are major pollinators of plants (second only to the wind, according to the article). Apparently there are more than 5 million acres (2 million hectares) under distribution lines in the U.S.. Few national parks in the U.S. (or anywhere else) are that large. If power distribution companies can be convinced to adopt conservation-oriented policies in the management of these areas, then a substantial envioronmental win is in the offing. That, and some truly awful corporate double-speak next time a cluster of cancer sufferers is observed near power lines.

Wednesday, August 24, 2005

Placebo effect not a placebo

It appears that the placebo effect has a physiological component, not merely a psychological one. According to New Scientist, a researcher has demonstrated the actual creation of endorphins in the brain in response to a placebo.

Thursday, August 18, 2005

Hydrogen for your fireplace

Cool idea. Provide water and power to your fireplace, electrolyse the water in situ and burn the resulting hydrogen! No mess, no flue, no CO-poisoning risks.

They start at only (!) US$35000 from heat-n-glo.

(via gizmodo via ohgizmo)

Monday, August 15, 2005

Xen process migration, filesystem options

Last weekend I was at UKUUG's Linux 2005 event and, amongst other things, learned a bit about Xen. Most impressive is its process migration (need to replace the hardware that a Quake3 server is running on? while players are using it? no problem; in the tested system, the service interruption was just 60ms, which client prediction can ordinarily be expected to cope with anyway).

A pre-condition for migration is access to the same filesystem(s). Amongst the options are SAN devices, NFS/CIFS (but remember to include /!) and some interesting filesystems/drivers that I'd not encountered before:
  • DRBD, which appears to perform RAID over a network, and can handle master/copy switchovers on the fly.
  • Lustre, which provides a DFS for giant clusters (up to tens of thousands of nodes) where not only is user/authentication seperated from file storage, but so is file metadata storage, the latter being on a seperate cluster built just for this purpose. The data itself is on whatever devices are in use for storage, but those devices don't mediate sessions, handle coherence, etc., they're "just" dumb storage, all the smarts are in the metadata cluster.

Thursday, August 11, 2005

Handy bash debugging trick

I've long been aware of

set -x

to cause bash to show what it's doing during script execution, however when debugging a long script (hundreds of lines) this may not be enough. If you additionally
export PS4='$LINENO '

, you'll get line number information as well.

Tuesday, August 09, 2005

Thinking outside the garbage can

Given the frequently impenetratable nature of language used by the legal fraternity, this concurring opinion (full ruling) on the constitutionality of a warrantless search of an individual's garbage in Montana is remarkable for its clarity. The closing words are priceless.

That said, if this Opinion is used to justify a sweep of the trash cans of a neighborhood or community; or if a trash dive for Sudafed boxes and matchbooks results in DNA or fingerprints being added to a forensic database or results in personal or business records, credit card receipts, personal correspondence or other property being archived for some future use unrelated to the case at hand, then, absent a search warrant, I may well reconsider my legal position and approach to these sorts of cases--even if I have to think outside the garbage can to get there.

Paul Graham on What Business can Learn from Open Source

The whole article is an interesting read (broadly: the value of paternalistic top-down structures over free-wheeling bottom-up ones is diminishing in many places at present, and is likely to continue doing so for quite some time). He does, however, make some wonderfully pointed remarks about typical corporate workplaces:

Another thing blogs and open source software have in common is that they're often made by people working at home. That may not seem surprising. But it should be. It's the architectural equivalent of a home-made aircraft shooting down an F-18. Companies spend millions to build office buildings for a single purpose: to be a place to work. And yet people working in their own homes, which aren't even designed to be workplaces, end up being more productive.

...

The atmosphere of the average workplace is to productivity what flames painted on the side of a car are to speed. And it's not just the way offices look that's bleak. The way people act is just as bad.
He also notices, in a roundabout way, something that I realised a long time ago about the worldview of many people who scorn capitalism:
The third big lesson we can learn from open source and blogging is that ideas can bubble up from the bottom, instead of flowing down from the top. Open source and blogging both work bottom-up: people make what they want, and the best stuff prevails.

Does this sound familiar? It's the principle of a market economy. Ironically, though open source and blogs are done for free, those worlds resemble market economies, while most companies, for all their talk about the value of free markets, are run internally like communist states.
My take on this is that corporatism is simply another word for using a firm (or firms) as the means of co-ordinating means of production, as distinct from using markets for the same purpose. An untrammelled excess of either creates harmful consequences. Many people protesting the evils of capitalism (private ownership of the means of production) are actually protesting the evils of very large scale corporatism (huge firms, whose executives wield enormous and largely unconstrained power over the masses). I consider this distinction important because most of the people I see/hear protesting capitalism actually advocate socialism, of one sort of another, unaware that they are advocating the construction of even larger corporations, which are even more dehumanising and, worse still, which have absolute monopolies in the areas in which they are to operate. The very problems that inspire such people to act appear to me to be the unavoidable consequences of the course of action that they advocate.

Anyway, enough rant. I really quoted Paul's article because of his amusing analogy of the extraordinary competitiveness of open-source software and blogging with encumbent software and media companies to the (not yet seen in the wild) idea of home made aircraft beating F-18s.

(It suddenly occurs to me that, of course, something akin to this has actually occurred. A handful of amateur criminals removed the World Trade Center armed only with box cutters... I'll stop now, really.)

Monday, August 01, 2005

Computer Security Calendar

Some very pithy info-security observations in A Year of Agony