here’s an interesting list of 5 resolutions for programmers for 2011. To summarize:
A presentation by Rich Hickey to the Western Mass. Developers Group on Clojure and concurrency. Brief overview of Clojure, discussion of concurrency issues, locking, and immutabiity. In-depth look at Clojure’s refs, transactions and agents. Demonstration and review of code for a multithreaded ant colony simulation.
I am a half hour into this, I’m up to the part on using Explicit locks for implementing concurrency. This is the old way of doing concurrency, as Clojure has built in support for concurrency. About 2 more hours in this video. Rich Hickey is the author of Clojure, this looks like a good talk.
There is another video at blip.tv by Rich Hickey, that looks interesting, called Hammock-driven Development. Described as: Rich Hickey’s second, “philosophical” talk at the first Clojure Conj, in Durham, North Carolina on October 23rd, 2010.
I watched a video presentation of Node.js, by the author Ryan Dahl. It explained the concept. He used some simple code examples. Mainly he emphasized that blocking I/O should be avoided. One thing that bugged me, he dropped down to the shell to illustrate, and while it was projected on a screen, the camera man, if there was one, did not pan to the screen. The first few characters of each line was visible, which made it that more frusrating.
This video was 48 minutes and kind of thin as compared to Martin Odersky’s presentation on Scala, which was dense with material.
There are more Node.js videos at blip.tv, including:
I watched a video tutorial called Scala – A Scalable Language by Martin Odersky, the author of the language. He described the design and syntax of Scala. He blazed through the tutorial which had lots of example code, occasionaly dropping down into emacs, which was projected onto to the screen, to illustrate the REPL (Read-Evaluate-Print-Loop).
Scala handles concurrency, has closures, traits and pattern matching. Traits are a sort of interface.
Functions are first class objects.
The REPL is called scala and their is a web framework called lift.
Martin talked about the tools available for Scala and mentioned with a straight face that he “uses emacs because he is old.” There was no reaction from the audience to this statement, even though there were older programmers present.
Scala interacts well with Java. In fact it seems like knowing Java would be a good idea.
I just finished watching the Loopage video by David Crockford. He claims, at the end of the video, that Javascript is leading the way to Event Driven I/O. He compares threads to non-blocking I/O:
after running ./configure get these:
Checking for header port.h : not found Checking for header sys/event.h : not found Checking for function kqueue : not found Checking for library execinfo : not found
went ahead and built any way, the node google group says it is okay.
I decided to repartition a 320 Gig drive I had, that was already partitioned into 4 lvm partitions. I needed something to use for backuppc, which I installed on my Ubuntu desktop. This time I created 1 big pv partition of the whole drive. Then I created a vg partition and used the name of the drive to name it, because I always get confused what lvm partition is on what drive.
Pick one of the install methods in this gist.
npm install connect socket.io
# start the redis server
wget http://redis.googlecode.com/files/redis-2.0.4.tar.gz
tar -zxf redis-2.0.4.tar.gz
cd redis-2.0.4
make
./redis-server
# install the node library:
npm install redis hiredis
I just discovered how to use less on non-text files, thanks to Linux Journal.
In Ubuntu, at least, we have /usr/bin/lesspipe. Then set the LESSOPEN environment variable like so:
> export LESSOPEN=”| /bin/lesspipe %s”
Which allows us to do this:
> less archlinux-2010.05-netinstall-i686.iso
CD-ROM is in ISO 9660 formatSystem id: LINUXVolume id: ARCH_201005Volume set id: Publisher id: Arch Linux <http://www.archlinux.org>Data preparer id: prepared by mkarchisoApplication id: Arch Linux Live/Rescue CDCopyright File id: Abstract File id: Bibliographic File id: Volume set size is: 1Volume set sequence number is: 1Logical block size is: 2048Volume size is: 81799El Torito VD version 1 found, boot catalog is in sector 321NO Joliet presentRock Ridge signatures version 1 foundEltorito validation header: Hid 1 Arch 0 (x86) ID ‘Arch Linux <http://www.’ Key 55 AA Eltorito defaultboot header:
2 things I finally got around to doing: