JJinuxLand

In my last post, Linux: My Mouse Ate My Homework!, I explained how dangerous it is to have a touchpad configuration that isn't finely tuned when you're running Ubuntu on a MacBook. For some reason, I've always been happy with the touchpad configuration under OS X, but I've never managed to set it up just right under Ubuntu. I spent three hours yesterday reading the synaptics man page (which is very well written, but not always helpful) and tweaking the settings.

In this post, I'm going to document the settings I came up with. I invite you to submit comments if you've found settings that feel more natural and are less likely to cause inadvertent mayhem. I'd be especially interested if you managed to get palm detection working.

First, start by creating /etc/hal/fdi/policy/appletouch.fdi as root:<?xml version="1.0" encoding="ISO-8859-1"?>

<!--
To learn more about this file: man 4 synaptics

Check for updates to this configuration…

One of the biggest challenges with using Ubuntu on a MacBook is getting used to all the "fun features" offered by the Synaptics touchpad, especially if you have big, clumsy hands like I do.

For instance, by tapping two fingers on my touchpad with a blank desktop, I can create a folder named "Untitled Folder". I'm not sure why I would want that, but it's definitely convenient! The problem is that a two finger tap opens up the context menu, and another tap selects the first item in the menu--which is to create a new folder named "Untitled Folder".

Another fun feature is that when I accidentally brush the touchpad with my palm, it'll find the virtual desktop where my browser is running and start scrolling the window. If I try to brush the touchpad in the opposite direction to get back to where I was, it just scrolls the browser in the opposite direction. That's because a two-finger drag on a blank desktop starts flipping through all the vir…

My buddy Andreas Schobel and I both use jQuery. He was mentioning to me that his page was getting too big, and setting up all the event handlers was taking too long. He noticed that FriendFeed also uses jQuery but doesn't have this problem. In fact, he couldn't figure out how FriendFeed's click handlers even worked. We decided to investigate.

We started investigating this file. It was minimized, so we ran it through the Javascript Beautifier. This reindents the code. However, it can't deduce the original variable names for local variables. That makes understanding the code a little harder, but it's still possible.

We started looking for instances of the word "click". It looked like the file contained jQuery plugins that made use of the click function, but the main app didn't. We saw this line:var clickHandlers = {};And a bunch of functions like:clickHandlers.expandcomments = function (A) {...};However, we couldn't find any place that was a…

I just watched the video for 960 Grid System. What a weird idea: constrain the page to 960 pixels and cut it up into 12 columns. When laying out your page, each piece fits into one or more contiguous columns. It might make more sense if you look at their examples.

Naturally, I knew about YUI Grid, but for some reason, watching the video for 960 Grid System helped me envision how I might actually use it. I've never really been good at super complicated layouts without using tables, but this seems easy enough to use. There's even a version of the CSS that isn't limited to 960 pixels.

Anyway, I'm not saying I'm going to convert all my sites, but I do think it's weird that somehow constraining yourself to fixed numbers like 960 pixels and 12 columns leads to greater flexbiliity. Since I'm a fan of haiku, that kind of makes sense to me.

I upgraded to Snow Leopard today. The upgrader refused to run until I deleted my Linux partition:When trying to install Snow Leopard, some people are having a problem where the installer will not recognize the current boot drive as a valid destination for Snow Leopard. Instead, it will display the drive with a yellow triangle on it, indicating something is wrong with that drive. When the drive is selected, the installer claims the system cannot boot from the drive. From cnet.There's more about the issue here. Once I upgraded, I found out that when you upgrade OS X, you have to install all your MacPorts from scratch. Hence, I didn't get much work done today. On the bright side, I really like one of the new backgrounds! ;)

I'm thinking of trading my MacBook on Craigslist for an IBM Thinkpad T61p.

If you add a unique index to a column in a database table, the database will prevent you from having two records with the same value for the given column. Rails has similar functionality at the application level. However, just like with foreign keys, the application isn't in a good position to enforce such a constraint. As soon as you have multiple application servers hitting the same database, it becomes obvious that only the database is in a position to enforce the constraint without suffering from ugly race conditions.

Ok, so how do you let the database enforce the constraint, but still handle duplicate records gracefully? Start with adding the unique index to the database in a migration:add_index :wishlist_books, [:user_id, :book_id], :unique => trueNow, instead of creating the record directly in the controller, call a method in the model:current_user.add_book_to_wishlist(book)In the user model, you might have something like this:# Add a book to the wish list.
#
# This is …

I just finished watching Writing Code That Doesn't Suck by Yehuda Katz. I think he also could have called it "Writing Tests That Don't Suck". I'm going to write a summary of some of his points (along with some of my own notes). He covers a lot of the things I've been thinking about over the last couple months as a Python coder coding in Rails using behavioral driven development (BDD).

Most Rails programmers agree that tests are good. However, we don't spend enough time considering which tests are the most valuable. In fact, Yehuda points out that a lot of tests are quite useless.

Unit tested code doesn't mean bug free code. In my own experience, I'm often so tired after writing automated tests that I don't have enough mental energy to do solid exploratory testing. Having someone other than the programmer do some serious exploratory testing is necessary.

alias_method_chain is bad. Having a chain of modules monkeypatching the same method le…