Journal

Excursions

Excursions, live hip hop jam in London and Brighton backed by superb jazz band.

Kent Beck on Interface Testing

I don’t like user interface-based tests. In my experience, tests based on user interface scripts are too brittle to be useful. When I was on a project where we used user interface testing, it was common to arrive in the morning to a test report with twenty or thirty failed tests. A quick examination would show that most or all of the failures were actually the program running as expected. Some cosmetic change in the interface had caused the actual output to no longer match the expected output. Our testers spent more time keeping the tests up to date and tracking down false failures and false successes than they did writing new tests.

— Kent Beck (1989)

This reminds me when Digg got bought and turned itself back into a startup, the first thing that went after a staff cull was the Selenium tests.

Restriction

“I don’t need time, I need a deadline.

― Duke Ellington

A Portable Bash Function to List Process Hierarchies

It can be useful to find the process hierarchy of a particular process when diagnosing a problematic machine. Say for instance you run into a rogue program and want to find out what spawned it before you kill it. The Unix command pstree (or ptree on Solaris) will show you a tree of running processes but is not always available.

Since I ran into this problem recently, I concocted the following recursive function to traverse a process tree to its root from a given pid:

parents(){ :(){                                                                                                                       
          read p n <<<`ps -o ppid,comm -p $1 | awk 'NR>1{print $1,$2}'`;
          echo -e "$1\t$n";
          test $1 -ne 0 && : $p; };
      : $1; }

Let’s see it in action:

stevechallis:~$ parents 28311                                                                                                         
28311   /bin/sh
488 /Applications/Emacs.app/Contents/MacOS/Emacs
1   /sbin/launchd
0

NASA Astronomy Picture of the Day Background

Update: An improved version of this script now lives on Github Gist at https://gist.github.com/1144996

NASA have this really neat Astronomy Picture of the Day webpage with some incredible pictures. I thought it’d be neat to set these as my desktop background picture so wrote the following script to accomplish this. It basically downloads the most recent picture to whatever folder you put it in and will wipe the folder whenever run. Adding this to a daily cron and then setting your desktop background to image.jpg should give you a changing picture.

#!/bin/sh
dst=`dirname $0`
base="http://apod.nasa.gov"
rm -rf $dst/*.jpg
wget -qO- http://apod.nasa.gov/apod.rss |
    grep "link" | head -n 1 |
    sed "s/.*<link>\(.*\)<\/link>.*/wget -qO- \1/" | bash - |
    grep "href=\"image" | head -n 1 |
    sed "s;.*\"\(.*\)\".*;wget -O $dst/image.jpg $base/\1;" | bash -

The accompanying crontab entry will be something along the lines of:

0   0   *   *   *   ~/Pictures/Wallpapers/apod/getpic.sh

Cute qmail Error

Hi. This is the qmail-send program at example-relay.com.
I'm afraid I wasn't able to deliver your message to the following addresses.
This is a permanent error; I've given up. Sorry it didn't work out.

<recipient@example.com>:
127.0.0.1 does not like recipient.
Remote host said: 571 from 127.0.0.1 We do not relay
Giving up on 127.0.0.1.

It’s good to see error messages that were written for people, not just machines.

Flash Player woes

Google’s Chrome browser ships with a different version of Adobe Flash player (10.1.103.19 ) than the current release (10.2.161.23) and is causing various problems for me, most notably the inability to stream my webcam.

Luckily it’s easy to disable. Just visit chrome://plugins and expand to details view. There will be two version of Flash and you can disable the problematic one to fix the problems.

In addition, the version of flash that shipped with OS X 10.6.5 is buggy and may need to be upgraded. I found installing the latest 64bit release alleviated the problems.

Full speed fans on a G5 running Squeeze

I recently put Debian Lenny on my Powermac G5. So far it’s been ok but after upgrading to Squeeze the Mac went into vacuum cleaner mode: running the fans at full speed – very annoying. Turns out the necessary thermal modules weren’t getting loaded anymore because initramfs-tools was broken. The necessary module is different on each model of Mac and since I have model PowerMac7,2, I needed therm_pm72:

Quick fix

modprobe therm_pm72
echo "therm_pm72" >> /etc/modules

Fix the actual problem

Update initramfs-tools/hooks/thermal with the following patch.

Incremental Backups Using rsync

We can combine rsync and cp -al to create what appear to be multiple full backups of a filesystem without taking multiple disks’ worth of space.

This is a really neat and efficient method for backing up data which utilises the fact that rsync will always unlink an inode before overwriting it.

Paint.ly looking for beta testers

We’ve just launched Paint.ly into beta and are looking for 500 eager mobile artists to test it. If you are such an artist then go ahead and sign up at http://paint.ly/signup with invite code ‘earlybird’.

Hopefully this’ll allow us to iron out major bugs and get some feedback from an exciting new community of people. Your feedback is really important to us so drop us an email with any comments and suggestions.

We look forward to seeing what you do with it!

Paintl.y is a new website that aims to make mobile art social. We’ve built the site from the ground up to work with the devices people are creating art on - tablet computers and mobile phones. We want the people who are driving the digital art revolution to have a place where they can share their work, as well as enjoying the work of their peers. Whether you’re new to art or been in the game a while, we’d love you to be a part of this community.