Monday, June 02, 2008

The Cargo Cult of Preferences

In a previous post I said that our tech support guys will trouble-shoot the most likely problems first (based on what we see in our entire user base) - they're playing the odds.

Well, a lot of our users do too.  Over and over and over I see the recommendation "delete your preferences" as a cure for a wide variety of strange symptoms.  And a lot of the time deleting preferences works.

I fear that deleting preferences has become a bit of a Cargo Cult, that is, a ritual induced to fix the mysterious beast that is X-Plane without consideration to why X-Plane is broken.  If the fix works, the previous problem is ignored.

Now here's the thing: preferences files are relatively small and easy to read!  And they're really easy to save.

So next time you have a problem and consider deleting the preferences, simply move them outside your Resources/preferences folder to the desktop and restart.

If the problem goes away, you can then delete the newly generated (clean) preferences and put the old funky ones back.

If you then truly find a situation where one preferences file causes the problem, you can look at what's actually different and file a real bug. (Unix nerds: most of the preferences files are text and can be "diffed".)

At this point, almost every option in the preferences file has a user interface item, so if the preferences file causes the sim to run poorly, there should be a setting that has been changed that can be identified.  Screenshots of the other airplanes, weather and rendering settings before and after the prefs might provide another quick way to compare what has changed. Control-period will take screenshots when dialog boxes are shown.

(Remember that the effect of preferences on framerate varies a lot with hardware.  There may be some preferences that slow fps a lot but do not make an obvious change in what you see "out the window".  By comparing two rendering settings screenshots you might find something subtle that changed.)

2 comments:

Chris Kern said...

I want to compliment you on your reference to "cargo cult." Not many people are familiar with the term these days. But the URL you provided leads to Richard Feynman's interesting, but derivative, definition. A better link would have been http://en.wikipedia.org/wiki/Cargo_cult.

Benjamin Supnik said...

Hi Chris,

Cargo Cults are near and dear to me...to me the most topical one is:

http://en.wikipedia.org/wiki/Cargo_cult_programming

But I figured I'd back off one stage in the derivation to Cargo Cult Science (a bit more generalized).