Here’s where things get a little buzzwordy: You might know that every computer needs a way to translate domain names (like “selfamusementpark.com”) into network addresses (like “192.168.1.5″); the Domain Name System does this (hence its catchy name, DNS).

When my computer wants to use a public network, it gets assigned a network address by the wireless base station, using something called Dynamic Host Configuration Protocol - DHCP. As part of this assignment, my computer also gets the address of a local DNS server address to use for name lookups. When I open my VPN connection, my computer automatically starts using my DNS server at home, to be able to look up the names of computers at home that aren’t on the public internet. (Yeah, I know: it’s weird that I leave the house to work on computers at home, huh?)

Here’s the catch: periodically, the base station requires my computer to “renew” its address, and when it does, my computer gets switched back to use the coffee shop’s DNS server (even though my VPN connection is still open). This is annoying, and I finally decided to look for a fix.

I found one in this Ubuntu bug. It’s a one-line change to a system script that prevents the DNS server switch if it’s happening because of an address renewal.

(Finding this took 30 seconds because I picked good search words, and applying the fix took 30 more because I understood what was going on at this level of the system. I’m blogging this because someone less technical than me might have more trouble with each; if this is something that bugs you and you have trouble with this fix, add a comment.)

It occurred to me that because the fonts were designed for legibility at small point sizes, Droid Mono might be a good replacement for the terminal font I do much of my programming in. It turns out that the whole family makes excellent replacements for the default fonts on my Ubuntu systems: they’re so legible that I’ve been able to reduce the default sizes as well, effectively giving me more screen real estate. Several times in the last couple of days, it’s occurred to me how much more beautiful my working environment is, now that I’m looking at a well-designed font.

You can get the fonts from within the Android SDK, but another helpful blogger has put them up as a separate download. (If you’re installing them on Linux like I did, put them in a folder in /usr/share/fonts, then do “sudo fc-cache -f -v” to get the system to notice them.)

“I find I’m so excited, I can barely sit still or hold a thought in my head. I think it is the excitement only a free man can feel, a free man at the start of a long journey whose conclusion is uncertain. I hope I can make it across the border. I hope to see my friend, and shake his hand. I hope the Pacific is as blue as it has been in my dreams. I hope.”

- Red, “The Shawshank Redemption”

I did find that right-clicking the project in the hierarchy and choosing “Android Tools” -> “Fix Project Properties” fixed this. Subsequent changes to the .aidl file automatically regenerated the .java file, too, so that’s nice.

Occasionally, though, I see strange problems during installs: apt-get install retrying the download of an apparently-cached package. I haven’t figured out what’s wrong, and frequently I just want to get the reinstall going again. In these situations, it seems optimal to just dump the cache and start over; I haven’t found clear documentation of how to do this, but in case it isn’t obvious, this works for me (my cache is in /var/cache/apt-cacher, and I run it as www-data):

# Stop the service
sudo /etc/init.d/apt-cacher stop
# Move the old cache out of the way, so we can delete it 
# in the background (it can take a while)
sudo mv /var/cache/apt-cacher /var/cache/apt-cacher.old
sudo rm -rf /var/cache/apt-cacher.old &
# Make the new cache hierarchy, and set its ownership properly
sudo mkdir -p /var/cache/apt-cacher/{headers,import,packages,private,temp}
sudo chown -R www-data:www-data /var/cache/apt-cacher
# Restart the service
sudo /etc/init.d/apt-cacher start

Update: I found this blog post helpful for manually removing troublesome packages from the cache.

• Rails 2.1.0’s ActionController wants version 0.6.1 or later of the ruby-prof gem, but the usual gem repositories only have 0.6.0 now. I found suggestions to install Jeremy Kemper’s fork on Github, but though I’d added GitHub as a gem source, installing jeremy-ruby-prof didn’t work because that installed his version with that name, which didn’t help ActionController. What worked was:

  sudo gem uninstall jeremy-ruby-prof # be sure to uninstall old attempts!
  git clone git://github.com/jeremy/ruby-prof.git
  cd ruby-prof
  rake gem
  sudo gem install pkg/ruby-prof-0.6.1.gem

• Then, script/performance/request ran, but generated several strange error messages instead of producing results:

  Couldnt get a file descriptor referring to the console
  Could not get a file descriptor referring to the console
  Couldnt get a file descriptor referring to the console
  Could not get a file descriptor referring to the console
  

  This turned out to be because script/performance/request wants to use ‘open’ to open its output files (a text file and an HTML document), but on Ubuntu, /usr/bin/open is a link to /usr/bin/openvt, which didn’t do what we want (and generated those error messages). I’m not sure what else uses ‘open’, but this did the right thing: it lets Firefox open the files:

  sudo ln -sf /usr/bin/firefox /usr/bin/open

That caused a problem, which the Pivotal Labs folks also commented on today:

When using named_scope, adding a :joins option will “mix-in” all of the attributes from that join table into your retrieved object, potentially overwriting any colliding attributes (including id … ouch!). There was consensus that this was a valuable feature, when used “properly”. Adding :select option can avoid this, or use :include.

Like they said, I fixed this with :select — the second try looked like this
named_scope :most_active, :select => "questions.*", :joins => :comments, :group => "questions.id", order => "count(questions.id) desc"

That worked (and fixed that problem), but it occurred to me that if my controller wanted to :include additional tables to add onto this scope (and that’s one of the cool things that named_scope enables), it wouldn’t work: Question.most_active.scoped(:include => :comments) raises a bad-SQL exception.

Fixing this required a bit of table aliasing, and led to this:
named_scope :most_active, :select => "questions.*", :joins => "left join comments as comments_for_count on comments_for_count.question_id = questions.id", :group => "questions.id", order => "count(questions.id) desc"

This worked, even with the :include added in a subsequent (anonymous) scope.

So a couple of years ago, to keep myself from going all Elvis in my senectitude, I adopted a rule: I’d only have a milkshake as we reached each thermometer milestone of 10 degrees Fahrenheit: I’d have one on the first day we hit 80°, one when we hit 90°, another at 100°, and should we hit 110°, I’d still be able to celebrate.

Unfortunately, I was cheated: I was out of town for the first two 90° days, then we went straight to 100°. (And no 110°, boo hoo.)

This year, I’m not taking any chances: I’m starting at 70°. I deserve it, too: we haven’t hit 70° yet this year, and we’re almost halfway through April already. I further deserve it because Cool Moon has been open since last November, just across the park, and I’ve been able to resist.

Tomorrow, however, the forecast is for 75° - Cool Moon, I’m coming for you.

1. Made salads & bread baskets, & worked the snack bar; Sandcastle restaurant, Malibu, 1978-1979
2. Parking attendant, Paradise Cove, Malibu, 1978-1979
3. Census taker, United States of America, 1980
4. Shipping/receiving & answering the phones, The Computer Store, 1979-1981
5. (Turned down by McDonald’s, 1978: hair too long.*)

* I know, doesn’t count, but I needed a fifth to honor my inspiration for this post.

Cut to yesterday evening: when I actually finished the work setting up ConferenceFanatic.com, I twittered about it (and mentioned that FestivalFanatic.com has Amazon DVD links now - hint, hint)… and as it happens, someone I follow (and who follows me) is presenting at the PostgreSQL East conference this weekend - she registered and told me about it using the feedback mechanism.

I also noticed that LinkedIn now has a Twitter-like mechanism, so I added a note there about my two sites.

Cut back to the present, 24 hours later: The PostgreSQL East schedule’s up, and half a dozen new people have signed up to use it. Also, I got a terrific email message from another ex-Apple-ite who’d seen the LinkedIn message, saying great things about ConferenceFanatic.com and what it can become - very encouraging.

(I also got feedback via this site’s mechanism, from someone about a startup opportunity - that was encouraging too; Derrek, I’ll be in touch.)