Posted by Kelvin on 03 Apr 2011 | Tagged as: Ubuntu
EasyHotSpot is an open-source hotspot solution built in PHP/MySQL on the CodeIgniter framework. It integrates with Chillispot and FreeRadius to provide a captive portal solution. Per-user bandwidth quotas are provided by way of "vouchers". A voucher is something you generate according to a "plan", e.g. 10MB voucher which expires 30 days from first-use. You can […]
Posted by Kelvin on 03 Apr 2011 | Tagged as: Ubuntu
In a previous post, I talked about my quest for a captive portal which supports per-user download quotas (and also explain what the heck a captive portal is). Here's a list of features which I was looking for in the Captive Portal: Free! Web-based administration Users need to login before having access to the internet […]
Posted by Kelvin on 03 Apr 2011 | Tagged as: Ubuntu
There are a number of free hotspot/captive portal solutions available on Linux, but believe it or not, not a single one of them offers daily per-user upload/download quotas. I ended up going with a customized EasyHotSpot solution which is based off the defunct Chillispot, FreeRadius and MySQL. Its way more involved than I initially thought. […]
Posted by Kelvin on 30 Mar 2011 | Tagged as: programming
Slacy has a fantastic post about what Larry Page really needs to do to return Google to its startup roots, but what I really learnt about it, was what life at Google is like as an engineer. 🙂 If you're too lazy to read the article, here's the bullet points: 1. Lotsa meetings (duh) 2. […]
Posted by Kelvin on 22 Mar 2011 | Tagged as: Ubuntu
Delete files older than 7 days: cd /path/to/dir find -mtime +7 -exec rm {} \; Change +7 to +14 for deleting files older than 14 days.
Posted by Kelvin on 13 Mar 2011 | Tagged as: programming
Recently when migrating from one server to another, my Java apps using an old version of Connector/J failed with this error: java.sql.SQLException: Unknown initial character set index '192' received from server. Initial client character set can be forced via the 'characterEncoding' property. No changes were made in the apps, so it had to do with […]
Posted by Kelvin on 08 Mar 2011 | Tagged as: programming
Akka is a Scala-based framework which promises "Simpler Scalability, Fault-Tolerance, Concurrency & Remoting through Actors" SO has a great thread on use-cases for Akka here: http://stackoverflow.com/questions/4493001/good-use-case-for-akka
Posted by Kelvin on 04 Mar 2011 | Tagged as: Ubuntu
Ever had your Intel wireless card play up on you in Ubuntu? You can't seem to reset it like the ethernet cards (i.e. with ifup and ifdown). Do this instead: sudo rmmod iwlagn && sudo modprobe iwlagn Replace iwlagn with your wireless card module name if you don't have an intel wireless card.
Posted by Kelvin on 01 Mar 2011 | Tagged as: programming
http://perfectmarket.com/blog/not_only_nosql_review_solution_evaluation_guide_chart has a lucid comparison of MongoDB, Redis, TokyoCabinet and BerkeleyDB. What's nice about the evaluation is that it mentions what use-cases which solution is likely to be a good fit. While we're on this topic, how about a recap of Brewer's CAP Theorem (pun intended)? And to round things up, checkout this Visual Guide […]
Posted by Kelvin on 01 Mar 2011 | Tagged as: programming, Lucene / Solr / Elasticsearch / Nutch, crawling
Just so no-one forgets, here's a recap of the Fallacies of Distributed Computing 1. The network is reliable. 2. Latency is zero. 3. Bandwidth is infinite. 4. The network is secure. 5. Topology doesn’t change. 6. There is one administrator. 7. Transport cost is zero. 8. The network is homogeneous.