Comments for Engineering Rapleaf http://blog.rapleaf.com/dev For engineers, by engineers. Thu, 09 Feb 2012 03:22:26 +0000 hourly 1 Comment on Can You Solve this Tropical Puzzle? by Lenoxus http://blog.rapleaf.com/dev/2011/06/29/can-you-solve-this-tropical-puzzle/#comment-13013 Lenoxus Thu, 09 Feb 2012 03:22:26 +0000 http://blog.rapleaf.com/dev/?p=3273#comment-13013 Actually, if the 500/500 ratio were already known, then all the islanders would leave on the first midnight possible, without having to do much thinking at all. Meanwhile, the visitor's comment does in fact cause new information to be known. Try it out with just 1 blue-eyed islander (and, say, 500 browns), then try it with 2, then 3, etc. In logicians' terms, the visitor's comment causes the existence of blue eyes to be common knowledge, meaning that everyone now knows that everyone knows that (repeat an infinite number of times) there are blue eyes, whereas before they noy knew this for up to 499 repetitions. Actually, if the 500/500 ratio were already known, then all the islanders would leave on the first midnight possible, without having to do much thinking at all.

Meanwhile, the visitor’s comment does in fact cause new information to be known. Try it out with just 1 blue-eyed islander (and, say, 500 browns), then try it with 2, then 3, etc.

In logicians’ terms, the visitor’s comment causes the existence of blue eyes to be common knowledge, meaning that everyone now knows that everyone knows that (repeat an infinite number of times) there are blue eyes, whereas before they noy knew this for up to 499 repetitions.

]]> Comment on Google Calendar + Arduino = The Roominator by The Roominator Against Conference Room Abuse / Cooking Hacks Blog http://blog.rapleaf.com/dev/2011/08/01/google-calendar-arduino-the-roominator/#comment-12993 The Roominator Against Conference Room Abuse / Cooking Hacks Blog Tue, 31 Jan 2012 12:32:59 +0000 http://blog.rapleaf.com/dev/?p=3383#comment-12993 [...] [Rapleaf] tried to solve this by creating a system to coordinate the (mis)use of room conferences The hardware consists of two parts: a display unit that’s posted outside of each conference room, and a controller unit that’s located in Rapleaf’s wiring closet. The display unit shows the current and upcoming reservations and an LED status indicator that can tell you from a distance whether a room is “good to grab”. It also has a pair of buttons – one to make an ad-hoc reservation and one to cancel the current reservation. The controller unit interfaces with all the displays to distribute power and data, both of which run over a single standard Cat5e cable. Both the controller and the displays are Arduino-based. [...] [...] [Rapleaf] tried to solve this by creating a system to coordinate the (mis)use of room conferences The hardware consists of two parts: a display unit that’s posted outside of each conference room, and a controller unit that’s located in Rapleaf’s wiring closet. The display unit shows the current and upcoming reservations and an LED status indicator that can tell you from a distance whether a room is “good to grab”. It also has a pair of buttons – one to make an ad-hoc reservation and one to cancel the current reservation. The controller unit interfaces with all the displays to distribute power and data, both of which run over a single standard Cat5e cable. Both the controller and the displays are Arduino-based. [...]

]]> Comment on Can You Solve this Tropical Puzzle? by Melvin http://blog.rapleaf.com/dev/2011/06/29/can-you-solve-this-tropical-puzzle/#comment-12973 Melvin Wed, 25 Jan 2012 23:16:17 +0000 http://blog.rapleaf.com/dev/?p=3273#comment-12973 My solution: Assumption: they live in a world where the blue and brown eyed people don't know if there are only 2 eye colors. In that case the blue eyed people will leave at night 500 and the brown eyed people will leave at night 1000. The blue eyed people will leave by induction (already explained here) and because they are gone, people could infer that since most people on the island have brown eyes, the counter will restart immediatly at day 501. Then via induction (again, same process) the brown eyed people will know after 500 days that they all have brown eyes. Because if they didn't they would've left at night 999. My solution:

Assumption: they live in a world where the blue and brown eyed people don’t know if there are only 2 eye colors.

In that case the blue eyed people will leave at night 500 and the brown eyed people will leave at night 1000.

The blue eyed people will leave by induction (already explained here) and because they are gone, people could infer that since most people on the island have brown eyes, the counter will restart immediatly at day 501.

Then via induction (again, same process) the brown eyed people will know after 500 days that they all have brown eyes. Because if they didn’t they would’ve left at night 999.

]]> Comment on Command-line auto completion for Hadoop DFS commands by dhamu http://blog.rapleaf.com/dev/2009/11/17/command-line-auto-completion-for-hadoop-dfs-commands/#comment-12953 dhamu Sun, 15 Jan 2012 21:13:47 +0000 http://blog.rapleaf.com/dev/?p=304#comment-12953 Finally managed to create the deb package for those scripts and uploaded those to my launchpad ppa. :) - https://launchpad.net/~kernel164/+archive/ppa Here is how to setup bash completion for hadoop commands using my ppa - http://cloudblog.8kmiles.com/2012/01/15/hadoop-setup-bash-completion-for-hadoop-commands-using-ppa/ Finally managed to create the deb package for those scripts and uploaded those to my launchpad ppa. :) – https://launchpad.net/~kernel164/+archive/ppa
Here is how to setup bash completion for hadoop commands using my ppa – http://cloudblog.8kmiles.com/2012/01/15/hadoop-setup-bash-completion-for-hadoop-commands-using-ppa/

]]> Comment on Command-line auto completion for Hadoop DFS commands by dhamu http://blog.rapleaf.com/dev/2009/11/17/command-line-auto-completion-for-hadoop-dfs-commands/#comment-12933 dhamu Sat, 14 Jan 2012 09:07:22 +0000 http://blog.rapleaf.com/dev/?p=304#comment-12933 Thanks ckline. I have published another bash completion script for hadoop commands at http://cloudblog.8kmiles.com/2012/01/14/hadoop-autocomplete-for-hadoop-commands/ Thanks ckline. I have published another bash completion script for hadoop commands at http://cloudblog.8kmiles.com/2012/01/14/hadoop-autocomplete-for-hadoop-commands/

]]> Comment on Command-line auto completion for Hadoop DFS commands by Hadoop: Autocomplete for hadoop dfs commands | 8KMiles Cloud Solutions Blog http://blog.rapleaf.com/dev/2009/11/17/command-line-auto-completion-for-hadoop-dfs-commands/#comment-12913 Hadoop: Autocomplete for hadoop dfs commands | 8KMiles Cloud Solutions Blog Fri, 13 Jan 2012 11:14:08 +0000 http://blog.rapleaf.com/dev/?p=304#comment-12913 [...] What I needed was an bash auto completion for those commands. A simple google search led me to rapleaf, but I wanted more… so here it is.. I made hadoop dfs autocompletion scripts.Plans: 1) To [...] [...] What I needed was an bash auto completion for those commands. A simple google search led me to rapleaf, but I wanted more… so here it is.. I made hadoop dfs autocompletion scripts.Plans: 1) To [...]

]]> Comment on Command-line auto completion for Hadoop DFS commands by ckline http://blog.rapleaf.com/dev/2009/11/17/command-line-auto-completion-for-hadoop-dfs-commands/#comment-12893 ckline Wed, 11 Jan 2012 18:40:10 +0000 http://blog.rapleaf.com/dev/?p=304#comment-12893 Wow, looks great @dhamu. Definitely an upgrade in functionality. Wow, looks great @dhamu. Definitely an upgrade in functionality.

]]> Comment on Command-line auto completion for Hadoop DFS commands by dhamu http://blog.rapleaf.com/dev/2009/11/17/command-line-auto-completion-for-hadoop-dfs-commands/#comment-12883 dhamu Wed, 11 Jan 2012 08:17:38 +0000 http://blog.rapleaf.com/dev/?p=304#comment-12883 Excellent article... I got inspired and did more changes on it... checkout here - http://cloudblog.8kmiles.com/2012/01/09/hadoop-autocomplete-for-hadoop-dfs-commands/ Excellent article… I got inspired and did more changes on it…
checkout here – http://cloudblog.8kmiles.com/2012/01/09/hadoop-autocomplete-for-hadoop-dfs-commands/

]]> Comment on Adventures in Java Garbage Collection Tuning by JavaDev http://blog.rapleaf.com/dev/2011/12/07/adventures-in-java-garbage-collection-tuning/#comment-12873 JavaDev Tue, 10 Jan 2012 18:10:16 +0000 http://blog.rapleaf.com/dev/?p=6423#comment-12873 Great post! My application also had the same issue -- some objects were getting tenured triggering full gc every few minutes. >>At the core of our problems with garbage collection is that we’re allocating a lot of memory in a very short amount of time. Addressing that issue will be the topic of a follow-up post. How did you resolve this issue? It would be great if you can shed some light. Great post! My application also had the same issue — some objects were getting tenured triggering full gc every few minutes.

>>At the core of our problems with garbage collection is that we’re allocating a lot of memory in a very short amount of time. Addressing that issue will be the topic of a follow-up post.

How did you resolve this issue? It would be great if you can shed some light.

]]> Comment on Matching Impedance: When to use HBase by Matching Impedance: When to use HBase | VC Ramesh http://blog.rapleaf.com/dev/2008/03/11/matching-impedance-when-to-use-hbase/#comment-12853 Matching Impedance: When to use HBase | VC Ramesh Sun, 08 Jan 2012 16:43:37 +0000 http://blog.rapleaf.com/dev/?p=26#comment-12853 [...] Matching Impedance: When to use HBase. Share this:Like this:LikeBe the first to like this post. [...] [...] Matching Impedance: When to use HBase. Share this:Like this:LikeBe the first to like this post. [...]

]]>