It can perform transactions at a much higher rate than that by using group commit, and any performance-sensitive system (including journaling file systems) will indeed use group commit. But the mean latency for any one commit does end up being limited to the time to perform half a disk rotation, and that's what non-volatile DIMMs are about - reduced I/O latency.

Because those battery tubes, to achieve their low filament-power consumption, used directly-heated cathodes (as you noted). If you think about this a bit further, you'll realize that this greatly limits the number of circuit topologies, because all of the cathodes in every tube must be connected together via the filament power supply. Imagine constructing logic gates where every transistor's emitter had to be directly connected to ground. Do-able, but limiting.

Megan McArdle is not a liberal source. http://www.balloon-juice.com/2011/08/04/under-pressure/

Yes! This is the book that taught me how to program. The rigor of Dijkstra's predicate calculus (aka Hoare triples) is sorely missed in today's bug-filled programming practice.

Planet Money is a joke. None of their correspondents are economists. David Kestenbaum is a journalist who happens to have a PhD in physics. Adam Davidson is not an economist; his background is journalism. Davidson clearly has a Milton Friedman bias in his economic reporting; just look at his blog posts on the subject of economic stimulus.

For a critical look at NPR (Nice Polite Republicans) check out the NPR Check blog.

Don't we want to encourage more fuel-efficient road vehicles? Seems like upping the gas tax would be a good way to do that.

Perhaps once we're all driving electric vehicles we might then consider a per-mile tax. Until then, the incursion on civil liberties and privacy from vehicle tracking doesn't seem to be outweighed by the societal benefits.

It seems to me that these vehicle-tracking ideas are a clever political scam that combines avoidance of a politically-costly raising of the gas tax, corporate welfare for some well-connected companies, and a plausible-sounding policy-wonkish cover story.

That's a little unfair; you've no citations in your post :-)

However, the fact that batons leave marks (physical evidence) whereas tasers do not implies that police are less likely to inappropriately use batons than tasers, since the inappropriate use of batons results in evidence visible to a board of review.

It's clear from news reports that police are overusing Tasers by using them as torture devices in circumstances where, if they had instead beaten the subject with a baton, the evidence of physical injury would have resulted in the censure or firing of the police officer.

The police baton is less likely to result in death.

Use the textbook "How to design programs" by Matthias Felleisen, Robert Bruce Findler, Matthew Flatt and Shriram Krishnamurthi., It's available free on the web or hardcopy from MIT press. Unfortunately the HtDP web-site seems to be down today. Check out the wikipedia entry. It's been used in high schools. They have a summer seminar for teachers, too.