Blue screen of the death on a Mac


Here it comes, first occurence: one of my VM’s BSOD-ed on me yesterday.


To be completely fair, I did have experienced an occurrence of something similar twice in last moths: after wake up from sleep, the screen was collection of the color pixels, completely unreadable. After reboot, everything was normal.

I found out that the issue may be related to the “safesleep” mode. For now, I disabled the mode by

sudo pmset -a hibernatemode 0

To re-enable SafeSleep, the command is:
sudo pmset -a hibernatemode 3

So far, everything works – but I am still investigating. Thanks to this thread (in German) for the hint.

Finally over 16 :-)


I did not even notice that the visit counter left the 16 bit domain sometimes during last few days. Now it shows about 67 000 visits. Honestly, I am pleasantly surprised how many people found this blog worthy their time :-). Thanks to you all …

Next boundary is of course 128K, 256K, 512K hits and finally a “Megahit”. But that’s far far away.

Rails 2 – really good tutorial


Akita published two part tutorial that leads you through building the famous 15 minute blog application in Rails 2.0. Read the parts one and two – or follow the screencast by the same author.

Thanks a lot, Akita – very nicely done !

The meaning of ORA-29907 error and the fix


I have first time encountered the error:

ORA-29907: found duplicate labels in primary invocations

after testing the change request we have implemented recently. The error message was not very helpful – I was not exactly sure which labels and which invocations 😉 – and as Oracle guru who actually does understand fine details of Oracle Text was visiting sunny India, I was on my own.

The change addressed an issue in repository search: users were asking for more flexible processing of full text search phrases: instead of e.g. searching for “unit test” search for document that contains both unit AND test. The text was parsed in Java and the SQL generator produced instead of something like

AND  ( CONTAINS(d1.document,'unit test',1) > 5)

AND  ( CONTAINS(d1.document,'test',1) > 5)
AND ( CONTAINS(d1.document,'unit',1) > 5)

I am still unsure what primary invocation is, but the above mentioned ‘label’ was the number one. After changing the generator to issue sequence numbers in the CONTAINS, everything worked OK:

AND  ( CONTAINS(d1.document,'test',1) > 5)
AND ( CONTAINS(d1.document,'unit',2) > 5)

Starting Ruby on Rails 2 with Netbeans and AWDWR book


After some break, I got back to Rails land. The return is not as smooth as I hoped: since Rails 2.0, many things work differently and quite a few steps learned from “The Book” do not work any more. The issues are more often than not quite easy to fix, but there is quite a few of them.

All the following is related to NetbeansRuby build 6327 from Jan 26th with JRuby 1.1RC1

After installing NetbeansRuby and updating the Gems (Tools->Ruby Gems), the attempt to generate Rails application fails:

/Users/miro/Applications/ `report_activate_error': Could not find RubyGem activeresource (= 2.0.2) (Gem::LoadError)

        from /Users/miro/Applications/ `activate'
        from /Users/miro/Applications/ `activate'
        from /Users/miro/Applications/ `each'
        from /Users/miro/Applications/ `activate'
        from /Users/miro/Applications/ `active_gem_with_options'
        from /Users/miro/Applications/ `gem'
        from /Users/miro/Applications/

Looks like the gem updater somehow missed activeresource – maybe a problem with dependencies ?To fix this, manually install activeresource 2.0.2 – Tools -> Ruby Gems, New Gems, search for resource, install. This is list of the installed gems:

  • actionmailer (2.0.2, 1.3.5)
  • actionpack (2.0.2, 1.13.5)
  • actionwebservice (1.2.6, 1.2.5)
  • activerecord (2.0.2, 1.15.5)
  • activerecord-jdbc-adapter (0.7.2, 0.7)
  • activeresource (2.0.2)
  • activesupport (2.0.2, 1.4.4)
  • jruby-openssl (0.1.1)
  • rails (2.0.2, 1.2.5)
  • rake (0.8.1, 0.7.3)
  • rspec (1.1.3, 1.1.1)
  • sources (0.0.1)

By default, the Rails 2 selects Sqlite3 database. This is great choice if you use C-Ruby, but not so great for JRuby – see this post. After few frustrated attempts to find workaround, I decided to go with Ruby 1.8.6, updated (again) the Gems in system installation (the first updated upgraded JRuby gems) and decided to try out the Depot sample – just have something that works, rather than fighting with issues of both Rails 2 and my own bugs. To keep with the book, I stayed with MySQL (quietly running in VMWare virtual machine).

By the book I have generated Product model and Admin controller, but instead of seeing familiar screen, Rails responded with error:

Routing Error

No route matches "/admin" with {:method=>:get}

This can be fixed by addingmap.connect ‘:controller/:action’to routes.rb, but this is probably bad idea because it goes against REST design principles which Rails 2 tries to promote. But to go ahead with the example, I hacked it 🙂 and added scaffolding. Next error I got was:

 NoMethodError in AdminController#index

undefined method `scaffold' for AdminController:Class

RAILS_ROOT: /Users/miro/Projects/RAILS2/Depot
Application Trace | Framework Trace | Full Trace

/Library/Ruby/Gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:203:in `load_without_new_constant_marking'
/Library/Ruby/Gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:203:in `load_file'
/Library/Ruby/Gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:342:in `new_constants_in'
/Library/Ruby/Gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:202:in `load_file'
/Library/Ruby/Gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:94:in `require_or_load'
/Library/Ruby/Gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:248:in `load_missing_constant'
/Library/Ruby/Gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:453:in `const_missing'
/Library/Ruby/Gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:465:in `const_missing'
/Library/Ruby/Gems/1.8/gems/activesupport-2.0.2/lib/active_support/inflector.rb:257:in `constantize'
/Library/Ruby/Gems/1.8/gems/activesupport-2.0.2/lib/active_support/core_ext/string/inflections.rb:148:in `constantize'
/Library/Ruby/Gems/1.8/gems/actionpack-2.0.2/lib/action_controller/routing.rb:1426:in `recognize'

Scaffolding is one of the parts removed in Rails 2. :-(. I tried to install ‘scaffolding’, which led to another error:

NoMethodError in AdminController#index

undefined method `paginate' for #<AdminController:0x2cafe34>

RAILS_ROOT: /Users/miro/Projects/RAILS2/Depot
Application Trace | Framework Trace | Full Trace

vendor/plugins/scaffolding/lib/scaffolding.rb:107:in `list'
vendor/plugins/scaffolding/lib/scaffolding.rb:95:in `index'
/Library/Ruby/Gems/1.8/gems/actionpack-2.0.2/lib/action_controller/base.rb:1158:in `send'
/Library/Ruby/Gems/1.8/gems/actionpack-2.0.2/lib/action_controller/base.rb:1158:in `perform_action_without_filters'
/Library/Ruby/Gems/1.8/gems/actionpack-2.0.2/lib/action_controller/filters.rb:697:in `call_filters'

Based on this post, I installed classic_pagination, which resulted in another error when trying to enter new Product

 ActionController::InvalidAuthenticityToken in AdminController#create


RAILS_ROOT: /Users/miro/Projects/RAILS2/Depot
Application Trace | Framework Trace | Full Trace

/Library/Ruby/Gems/1.8/gems/actionpack-2.0.2/lib/action_controller/request_forgery_protection.rb:79:in `verify_authenticity_token'
/Library/Ruby/Gems/1.8/gems/actionpack-2.0.2/lib/action_controller/filters.rb:469:in `send!'
/Library/Ruby/Gems/1.8/gems/actionpack-2.0.2/lib/action_controller/filters.rb:469:in `call'
/Library/Ruby/Gems/1.8/gems/actionpack-2.0.2/lib/action_controller/filters.rb:441:in `run'
/Library/Ruby/Gems/1.8/gems/actionpack-2.0.2/lib/action_controller/filters.rb:716:in `run_before_filters'
/Library/Ruby/Gems/1.8/gems/actionpack-2.0.2/lib/action_controller/filters.rb:695:in `call_filters'
/Library/Ruby/Gems/1.8/gems/actionpack-2.0.2/lib/action_controller/filters.rb:689:in `perform_action_without_benchmark'
/Library/Ruby/Gems/1.8/gems/actionpack-2.0.2/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue'
/Library/Ruby/Gems/1.8/gems/actionpack-2.0.2/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue'
/Library/Ruby/Gems/1.8/gems/actionpack-2.0.2/lib/action_controller/rescue.rb:199:in `perform_action_without_caching'

I backtracked, and tried to go with generated scaffold, rather with dynamic. The generated views were named edit.html.erb, rather than edit.rhtml and the generator did not allow to enter controller (second argument). This lead to error


Template is missing

Missing template admin/index.html.erb in view path /Users/miro/Projects/RAILS2/Depot/app/views

At this point I gave up and decided to:

  • read the Rails 2.0 documentation (after everything else failed, read the manual …)
  • reconsider using AWDWR as the guide – obviously, it needs to be updated to be useful with Rails 2. If you purchased the PDF from Pargmatic Programmers, there is an update available on their website, but it is not an update for Rails 2 …

I was not the only person to try AWDWR with Rails 2. The best resource I found was Ruby Plus website with series of screencasts, starting with this. The author – Bala Paranj did great job in putting together very useful collection of Rails screencasts. If you want to use the AWDWR with Rails 2.0, listen to them first – unless you are very experienced Rails developer.

Showstopper issue with JRuby ?


After some break, I dusted off the Ruby to try out one interesting idea Peter presented yesterday that literally ASKS for Rails. So I grabbed the latest and greatest RubyNetBeans from Ruby Hudson. For some reason it stopped updates on January 26th so the latest version I have got was build 6327. It is bundled with JRuby 1.1RC1 and the Rails version that comes preinstalled is 1.2.6. Using the menu Tools -> Ruby Gems, they can be easily upgraded to latest and greatest 2.0.2.

The trouble begins when you want to install database connectivity gems such as sqlite3-ruby. The installer fails with the message:

trying to install

INFO:  `gem install -y` is now default and will be removed
INFO:  use --ignore-dependencies to install only the gems you list
Building native extensions.  This could take a while...
extconf.rb:1: no such file to load -- mkmf (LoadError)
ERROR:  Error installing sqlite3-ruby:
    ERROR: Failed to build gem native extension.

/Users/miro/Applications/<a href="" class="linkification-ext" title=""></a> extconf.rb install sqlite3-ruby --no-rdoc --no-ri --include-dependencies --version > 0

Gem files will remain installed in /Users/miro/Applications/<a href="" class="linkification-ext" title=""></a> for inspection.
Results logged to /Users/miro/Applications/<a href="" class="linkification-ext" title=""></a>

The missing file mkmf.rb is indeed missing from the JRuby distribution. This is entered as a bug in JIRA 1306 with resolution ‘Won’t fix’. Tough luck.

I understand the reasons and motivation for this decision – the JRuby team decided not to support native extensions in Gems, to keep the platform Java only. I also understand that in this particular case, there are workarounds – using ActiveRecord-DBC gem and JDBC drivers for the database will most likely work. Unfortunately, this decision makes choice of JRuby as platform very questionable.

I really liked JRuby for the comfort of having platform that is portable and safely wrapped within boundaries of the good old trusted JVM. I feel much more comfortable maintaining possibly several different versions of JRuby and corresponding Gems sets than maintaining same several configurations on the OS level and sudo-ing just to install Gems. I was more that happy to trade the lack of speed for this security.

The two main attractions of Ruby (from my point of view) are elegant, powerful language with beautiful syntax as well as sheer amount of code available as Gems to be reused. With the bug 1306, many of this code may not be available for JRuby – unless Gem authors make specific provisions for Java version of the Gem. I cannot think how this is a good idea and certainly not a good news for the future of the language.

One way out is use native Ruby interpreter, of course and make sure you do not mess up your installation by trying out new things. This does not allow the easy way into enterprise that JRuby was promising – by being basically ‘just another jar’ and running on Tomcat.
The other way out is to reconsider the Groovy. I still do not enjoy the syntax anywhere close to Ruby, but every Groovy class is Java class, there is no need for artificial bridges. It has own clone of Rails – GRails – that seems to provide lots of Rails magic and goodies and is based on Spring which I am very familiar and quite happy with. I still do not know whether the amount of “gems” in Groovy world is in the same league as Ruby (which is still limited compared to Python or even CPAN Perl bonanza) – but as long as I can find that what I need, it may be just enough.

For now, I will revert back to Ruby (no time to start learning Groovy+Grails), but I definitely will look at it later on.

On White Stuff and Other Disasters


Guess what are three most useful tools without which no proper Ottawa household can exist ? Snow shovel, snow pusher and car window ice scratcher. If the number was 4, the next would be snowblower. Up to yesterday, our family was in safe position being equipped with several shovels, four or five scratchers and one pusher.

Then disaster stroke: my son broke the pusher while moving away few cube meters of snow we removed from the roof. In case you do not understand – removing snow from roof is another favorite winter leisure time activity in Ottawa: almost everybody is doing it. Not that it would be so much fun, but because of the dreadful consequences – avoid it and you may end up like this guy.

Especially in year rich on snow, like this one. And this winter – despite beig warm and cosy, only few days of -25 and below – it is snow-wise very likely a record year. The previous record winter happened (fortunately) long before I set foot on this continent: in 1970-71, we had 444 cm of snow during winter. Right now, it is about 415. The weather forecast for next week mentions possibility of another 50 cm. Ouch.

picture-19.pngThe shoveling is no fun at all. The back garden is full of snow, with top of the snowhill well over 3 m high. Another mountain in front of the house. I can hardly imagine where we do put another 50 cm, and most importantly HOW. Because the darn pusher is broken.
Now if you think that in modern market economy it is just a matter of driving to next store and buying one, think again. This is what I did today, just to discover that full Garden and Outdoor section is filled with barbecues, rakes, seeds, lawn movers and other completely ridiculous tools :-). No pushers at all. Only small pack of deserted shovels set aside. I bought one to make the trip worth the time ….

I guess I will have to BORROW a pusher from neighbor :-(. What a shame to admit I am pusher-less …

Out of desperation, I have decided to share my experience with the public in the following book:
Snow Shovelling