Philip Greenspun’s Weblog

In the mid-1990s when I started building online communities I didn’t understand why publishers like Amazon pre-moderated all user-contributed content such as comments.  The vast majority of users were intelligent and well-meaning and only a small fraction of material had to be deleted.  It seemed like it wasn’t worth interrupting the flow of conversation and exchange to ensure that an off-topic posting never saw the light of day.  It would be intercepted within a day or so and deleted in any case.

The Manila software that Harvard runs behind these blogs shows the foolishness of my point of view.  More than 90 percent of the comments posted to this blog are link spammers trying to increase their Google rank by adding comments to old and forgotten postings.  Manila makes it impossible to delete this spams except one by one, each one requiring a several page process of confirmation.  In the old ArsDigita Community System we had a “delete all from this user” and “delete all from this IP address” option that made it a lot easier.  But in the Age of Spam what we really need is pre-moderation.  Maybe there should be an option for a vibrant interactive discussion that content goes live for 24 hours without being approved but otherwise given the small percentage of useful non-spam content it seems that the only answer is that nothing goes public without approval.

Another reason to program in pre-approval only is that eventually the moderators of every online forum find other things to do with their lives.  The server doesn’t realize this and soldiers on processing postings.  Spammers discover a happy home and the database fills up with crud.  Software should be robust to the moderator disappearing and in an Internet that is mostly spam that means approval-required-before-going-live.

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Friends have been asking me for an explanation of the Air France Airbus crash in Toronto yesterday.  It is tough to say without a full accident report.  Whatever the report concludes the accident will underscore the important point that a pilot should never commit to a landing.  There is a temptation in aviation, especially after a long flight, to conduct the approach and landing as though it is inevitable that the plane must continue to descend and stop on the runway.  Unless you’ve run out of gas or suffered some sort of catastrophic engine failure in a single-engine plane, however, there is nothing inevitable about continuing the approach and landing.  A pilot can at any time make the decision to add power and go around.

When does it make sense to go around?  The airlines have rules about stabilized approaches.  The plane should be at the right airspeed, at the right position laterally and vertically, at the right descent rate, and configured for landing when it is still about 1000′ above the runway.  If not within tolerances, the pilots are directed to go around and, at least in training, they always adhere to these rules.  A light airplane is more subject to turbulence and has less inertia and therefore is easier to adjust.  The tolerances can probably be relaxed a bit and the deck lowered to about 500′ for a single-engine four- or six-seater.

Suppose that the winds are super gusty over an entire region, as is common here in the Northeast.  Or suppose that you’ve just flown many hours and are tired.  Or suppose that there are thunderstorms and it isn’t obvious where you could go that would be totally safe to land.  The rules get bent.  In general not nearly enough go-arounds are made by either small or big airplane pilots.  Usually the decision to fix a bad approach doesn’t result in an accident.  And indeed in Toronto these guys might have been okay if only they’d been on the 11,000′ runway 23 instead of the 9000′ 24L (the runways are oriented facing magnetic direction 230 and 240, i.e., almost the same, so it is unclear why the Airbus wasn’t assigned the longer runway).  They might also have been okay if they hadn’t been in the famously underpowered A340-300 (the newer versions of this plane have almost twice as much power) and therefore requiring more runway remaining before going around.

The cause of the crash might yet prove to have nothing to do with the pilots’ decisions.  Nonetheless it is probably a good idea for all of us who fly to remember to keep a hand on the throttle and tell ourselves that this is only an approach and that we won’t commit to the landing until we’re very nearly stopped on the runway.

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My new hero is John Kounis, editor of Pilot Getaways magazine.  He made a doggie headset to protect his Lab’s hearing:

“While flying [Woody] wears a special doggie headset made from kneepads, foam, and velcro straps.”

Photos http://www.pilotgetaways.com/behindthescenes/woody/pages/IMG_2367.htm and http://www.pilotgetaways.com/behindthescenes/woody/pages/IMG_5143.htm

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In the Fall of 2003 the idea of Web-assisted social networking, in the form of Friendster and Orkut, was still sufficiently fresh in folks’ minds that we were able to use Friendster as an example for a class (see http://philip.greenspun.com/teaching/6171/2003-fall/friendster ).  Going through the email that accumulated during the Alaska trip I noticed that (1) I had one new Friendster request, and (2) a spam email from Friendster noting that I hadn’t logged in for a year or more and inviting me to return.  So I logged in and the site is now pretty responsive but very few of my friends had logged in within the last 12 months.  I’ve not heard anything from Orkut in at least a year.

Do we pronounce Web-assisted social networking dead?  Or is it just that nobody wants to be friends with me?  🙁

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A friend of mine is moving to Chicago and needs a new car.  She is 25 years old, of medium height, and conservative in her tastes.  She wants a four-seat sedan with back seats large enough to carry passengers but very seldom will she have anyone in the back seat.  Cost is not an issue but she doesn’t want something that screams “I am a rich bastard”.  We test-drove the Acura RL sedan yesterday afternoon.  It seemed like it did just about everything that you’d want a car to do.  The RL is big but not huge.  It has great acceleration and reasonable mileage (18 city, 26 highway–not quite as good as the latest minivans!).  All four wheels are driven for better handling, especially in slippery conditions.  The seats are perfectly comfortable and heated (but sadly not air-conditioned; right now with global warming we really need liquid coolant flowing through the seats themselves).  A good navigation system is standard, complete with real-time traffic data for various cities, delivered via the XM radio.  Onstar is also standard.  Operating all of the electronics via the big control stalk/wheel/button/thingy seemed challenging but not impossible to learn.  The RL won Car and Driver’s “Best Luxury Sedan” award (I think they limit this to cars costing less than $70,000). The car lists for $49,000 but right now they are try to get rid of the 2005s at “employee” prices (on the radio in Alaska this proved to be around $43,000 but somehow the dealer in Boston wants $44,000+).

Are there any other cars she should consider?  I liked the Chrysler 300 that I rented in Yellowknife but I think they are selling for list price due to high demand, which would make an all-wheel-drive version almost as expensive as the RL.

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Suppose that you have a single computer in a room somewhere.  This plugs into an Ethernet jack in the wall.  At this point you want to add a wireless access point in case someone with an 802.11b/g laptop walks into the room.  Upstream is a router that provides DHCP to whoever asks.  What is the best way to add wireless access to this room?  My initial idea was that the simplest configuration, leaving all computers on the same subnet, would be to add a hub or switch and then plug both the existing computer and a new wireless access point into the hub/switch.  This would seem to be kind of annoying, though, requiring two little boxes and two little wall transformers.  A quick scan of the Linksys Web site doesn’t turn up any boxes that have just the switch and the wireless access point but not the router.  Is it easy to configure a Linksys router/switch/WAP box so that the router doesn’t actually route?  Is there some other company that makes a simple one-box solution?

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After renting dozens of new cars in the last year it struck me as odd that the factory stereos can’t do two simple things:  (1) bring an aux input out to the front of the dashboard for plugging in an MP3 jukebox, and (2) read a CD containing MP3 files.  These features would only add about $1 to the cost of the car and presumably would give MP3-crazed yupsters a reason to trade in their older vehicle.  You’d think that the car companies would jump at this chance to add value without adding cost.  Why aren’t they doing it?  And as long as they are tweaking their electronics you’d think that they would add remote start, something that would cost them $2 max and that consumers are willing to pay $400 for in the aftermarket.

[My favorite rental cars:  Chrysler 300 sedan from Hertz in Yellowknife, Ford Freestar minivan from Hertz in Anchorage (rented a mountain bike and kept it in the back; Alex loves the space to spread out), Toyota Avalon (redesigned for this year) from Hertz in Jackson, Wyoming, nimble Mazda 6 from Hertz in Oakland, California.

The worst rental cars:  various Pontiacs (GM had better hope that no potential customer ever test-drives a Chrysler 300), a Ford Escape SUV presented by Hertz of Quebec City as an “upgrade” from a Taurus (incredibly bumpy and ineffective suspension).]

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http://www.joelonsoftware.com/articles/HighNotes.html contains some hard numbers (halfway down) on the standard deviation in productivity among computer programmers.  The study is among a population of fairly bright folks (Yale undergrads) and even when only the best students are considered the standard dev. is still quite high.

[Note:  The article does not say whether or not the students were all using the same languages and tools but as the data seem to be from a course with a heavy emphasis on Unix code-monkeying it seems reasonable to assume that all of the students were using C.] 

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American women have seemingly achieved most of the goals of the folks in the 1960s who called themselves “feminists.”  Women can work 24/7.  Women can vote (for the white male of their choice, at least in the last few presidential elections).  Women can get abortions without having to travel beyond their home state.  Women constitute close to 50 percent of the young folks training for and holding jobs that are actually worth having (e.g., medical doctor).

What then does someone who calls him or herself a “feminist” think about in 2005?  http://melancholicfeminista.blogspot.com/ is an interesting place to start looking for the answer.

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I’ve decided to amuse myself and, I hope, inspire some young hard-working folks, by writing up ideas for businesses that should be profitable.  Here’s the first one:  http://philip.greenspun.com/business/chinese-rv

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