AWS Elastic MapReduce Webinar @Noon ET on May 28

Amazon's new Elastic MapReduce service makes it easier to run Map/Reduce jobs within EC2. If that sounds interesting, you can find out more about it by registering and "attending" the webinar they're holding on Thursday, May 28 at Noon ET. I'll be there, in a virtual sense. :)

ConcurrentLinkedHashMap and Possible Alternatives

I mentioned in an earlier post that a project I'm working on needed a thread-safe class with behavior similar to LinkedHashMap, which maintains the order of entries while allowing sub-classes to set a (rather primitive) eviction policy.  I came upon and started using Ben Manes's ConcurrentLinkedHashMap, with only minor modifications to allow for easier sub-classing.  I've been pretty happy with it so far and have been meaning to take a look at recent changes that he and "zellster" have made since I last downloaded the code.

The same project is also using ehcache for caching.  I was looking forward to the release of version 1.6 and inquired about the expected release date on the developer's forum.  That kicked off an exchange between me and Greg Luck, the lead for ehcache, that eventually led to him mentioning some problems he'd encountered with ConcurrentLinkedHashMap.  I'm going to check in with Ben and let him respond to what Greg said, along with giving him a chance to provide a guess for when his new version of CLHM is likely to be usable.  I also need to look into what Greg was referring to in the changelog for ehcache 1.6 beta5 when he said, "Make MemoryStore eviction policies injectable."  Interesting…

Just to confuse matters, I was also recently looking over some materials discussing Infinispan, which will essentially be the 4.0 release of JBoss Cache, and saw this interesting blog entry on "Implementing a performant, thread-safe ordered data container".  In it, Manik Surtani mentions their newly implemented classes FIFODataContainer and LRUDataContainer, which sound like another plausible way to approach my problem.  I'll make sure to ask more about them in the comments for that post.

JPC: x86 Emulator in Java

Last night, I was reading Caches and Maps in Terracotta by Alex Miller when I came upon his link to the JPC (a.k.a. JavaPC) Project.  It sounded familiar and I decided to follow the link.  It turns out to be an open source project implementing an impressively functional and performant x86 emulator in Java.  I had fun last night launching an MS-DOS environment within an applet (what a concept!) and playing Donkey Kong for the first time in ages.  According to the site, the emulated layer runs at about 20% of your processor's speed - not bad for a emulator written in pure Java.

Note: After my first visit to the site, it seemed to be having problems.  Just in case it had to do with visitor load, I changed the link above to point to the copy in Coral Cache.  The site is now totally back up and behaving normally.  If Coral has any problems or is slow, you can safely go to the site directly.

Update: I got an email from one of the JPC team members saying that they'll be at JavaOne this year with some new stuff.  I wish I could be there to see it.  I guess I'll have to wait for it to show up on their site.

Trying out DISQUS for Comments

I've decided to try out DISQUS for handling comments on my blog. Let me know what you think. I can always revert back to Blogger comments if desired.

Update: It turns out that there's a bug in Blogger that precludes you from using DISQUS in conjunction with an external post editor. Since I'm happy with Windows Live Writer, I guess I'll disable DISQUS for the time being and revisit the decision if the bug gets fixed.