Learning Idioms

Posted by skelter Thu, 16 Oct 2008 22:49:00 GMT

There’s learning idioms and there’s learning idioms.

Learning idioms, as in gaining knowledge of idioms, in a natural language as well as programming language. I don’t know that it is a specific skill, but it is definitely a general quality that is very useful in becoming productive in a new language. I have to think the two are related.

Made me think if idioms of learning. Will have to contemplate this. Generalized learning idioms might be useful in AI, but then might be useful in the real world, too, especially if you like to over-think things.

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NFJS wrapup

Posted by skelter Thu, 16 Oct 2008 22:46:00 GMT

wrap up some straggler blog notes about nfsf.

git: Version control very popular among the presentorgencia? (presentatti?) seemed uncomfortably unstructured, but will have to look into it.

Brian Geotz’s are always great, and the Java Memory Model talk was worth the time. This will become more important as we look at things like terracotta.

Architecture and Scaling by Ken Sipe inspired me to set up the scaling lab at work and get some real numbers out of our application.

Leading Agile Projects by David Hussman. I think what I need next in my career is some bone-head manager training. My people leading and direction skills are not geared to what I am having to deal with at work right now.

Ted Neward was using the Komodo editor in a pinch during his magic show act.

In the roundtable/grilling/QA, one of the presenters mentioned Bill Gates going on a reading weekend. I thought this was a full week. I was right, and it even has a name:Think Week.

I need to google a bunch of things, including

I’ll update this post with links as I go.

Did you know you can just randomly put curly braces in a Java class, outside of a method. Uhh. Kind of a party trick. I’m not sure if it’s gross or not.

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APC UPS's fail

Posted by skelter Tue, 14 Oct 2008 21:00:00 GMT

I have now had two APC UPS’s fail on me. Not battery failure, I mean the electronics die. Very frustrating.

I’ll try Tripplite and will avoid APC UPS’s.

I don’t need this. I have a life and I have things to do.

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Playing with TerraCotta 2.7.0

Posted by skelter Tue, 14 Oct 2008 16:41:00 GMT

I am playing with Terracotta clustering, the way it should be: on different machines.

Obstacle 1 - Binding to non-localhost address

  1. edit top level tc-config.xml <server> entry to bind to the public address
  2. Add a server line to the ClusteredHelloWorld/tc-config.xml to specify the server at that address

Obstacle 2 - Remote terracotta admin console access

Solution:

  1. Double check that the RMI stubs handed out are pointing to the resolvable hostname and not localhost or myhostname.local. See this helpful blog on hostname resolution on linux
  2. Enable authentication. admin console reports a timeout, but you are able to telnet to the port just fine, ruling out firewall issues. Server’s jmx is apparently handing out stubs, but still no joy. Turn on authentication and make sure the properties are set up, and admin console will prompt you for a username and password. See terracotta’s jmx guide. Would be nice if admin console helped diagnose this.

Conclusion - promising

Got the HelloClusteredWorld example going on two different machines hitting the same cluster. It’s a brain-dead hammering of a clustered object so I can see some performance grief, but it seems to be working find. This looks very promising. I am going to have to try some non-trivial prototypes.

Next stop: learn about ehcache.

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Dr. Bart Childs right again: Network Attached Memory

Posted by skelter Tue, 14 Oct 2008 16:18:00 GMT

My last year (1995) at Texas A&M University computer science, I had the pleasure of taking a seminar guided by Dr. Childs. One of the things he mentioned was coming was network memory. Your program will be able to address memory locations that refer to memory not on your machine, but over the network on a different machine.

Today, 2008, I am playing with Terracotta at work. It is intriguing. While the fallacies of network computing still apply, this is an interesting approach to clustering an object graph.

It is a wonderful time to be a developer. It is still profitable. The technology makes leaps on an almost overwhelming pace which increase my productivity. My children will probably never know CORBA, DCOM/COM+/OLE.

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SIGSEGV (0xb) at pc=0x0625665c Eclipse

Posted by skelter Thu, 09 Oct 2008 18:00:00 GMT

Today, out of the blue, after months of working just fine, I started getting the dreaded

 # An unexpected error has been detected by Java Runtime Environment:
 #
 #  SIGSEGV (0xb) at pc=0x0625665c, pid=22092, tid=349178768
 #
 # Java VM: Java HotSpot(TM) Server VM (10.0-b23 mixed mode linux-x86)
 # Problematic frame:
 # V  [libjvm.so+0x25665c]

I’m not on an amd64 platform. I’m on good ol’ Gentoo x86. However, I did compile the kernel with extended address space so I can make full use of the 4 gigs.

So now I am trying jdk1.6.0_10, reluctantly. Not sure what caused this to pop up now.

nice long error dump after the jump, but it’s mostly boring and only there for search engines.

Read more...

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n800 FAIL!

Posted by skelter Tue, 07 Oct 2008 04:39:00 GMT

upgraded OS. Now Rebooting all the time!

Boo!

4.2008.32-5 Bad!

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Hacking the JDK

Posted by skelter Tue, 30 Sep 2008 20:55:00 GMT

Notes from Ted Neward’s Hacking the JDK

NFJS/NESS 2008

Ballsy presentation. format: Audience picked from lists and Ted did it.

  • Binary hacking
    • modifying the JVM settings at runtime
    • changing the JDK security policy at runtime
    • call private mthods, get/set private fields
    • load code remotely from an http server and other place
    • ignore CLASSPATH and -Djava.class.path
    • slipping your own clases ahead of thE jdk’S
    • Modifying byte code during load
    • embedding the JDK in your own (native) code
  • Source hacking
    • modifying the Java launcher (java.exe)
    • modifying the java class library
    • modifying the java compiler
    • modifying the JVM

see slides

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Viva la Javolution

Posted by skelter Tue, 30 Sep 2008 19:20:00 GMT

NFJS NESS Notes from Brian Sletton’s talk Viva la Javolution

This was primarily about Javalution, a kit and api useful for producing java code with predictable performance, important for embedded systems. Not useful for my current use, however a spun-off project, JScience, contains a UOM api which may prove useful.

I had talked with Scott Davis about his talk about YSlow and reviewed the slides. It looked like I could pick up on the aspects of the tool, and make use of it and the techniques it mentions on my own.

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Branding build version into manifest and retrieving with Package.getSpecificationVersion

Posted by skelter Thu, 25 Sep 2008 23:14:00 GMT

You would expect this to be straight forward but it isn’t quite all there. Even then, there is a slew of bugs in the Sun Java bug parade that are worth looking at.

  1. the Implementation-XXX and Speicification-XXX must be in a section for the package
  2. the section name is slash separated and MUST have a trailing slash.
  3. some of the docs and specs reference Package-XXX but we don’t see this “manifesting” itself (nyuck nyuck nyuck).
Read more...

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