UNIX tip: from chmod(1): “The letters ‘rwxXstugo’ select the new permissions for the affected users […one option is:] execute only if the file is a directory or already has execute permission for some user (X)”. That is, when, for whatever reason, you’ve got a whole tree of files and directories, and you can’t enter some number of sub-directories because their execute bit isn’t set, you can either execute chmod -R u+x my_dirs, or, you can (now) execute chmod -R u+X my_dirs. The former will make all the files executable (Bad™) while the latter will make only directories enterable (or, otherwise-executable files executable for you). Handy to know.

Have you ever wished you could sort all of the people you follow on Twitter by how frequently they update? Here is a Ruby script that will do that for you. It asks Twitter for your friends, and uses Gene Smith’s Tweeterboard.com to determine update frequency. (Follow tweeterboard to let it know to track your stats).

To use the script, simply download it below, edit the constants at the top of the file, at run: ruby friendstats.rb. (Optional step: unfollow your boring-but-prolific “friends”).

Feedback appreciated. Usual disclaimer applies: beware, may kill your cat, I’m not liable, etc.

I’ve just released Snippits 0.5.2, my Ruby text expansion program for Linux. This version contains mostly bugfixes and documentation updates. The full changelog is below. I also have put together a roadmap of future versions of snippits, and what they might entail. Take a look; any feedback is appreciated.

• Bugfixes
  • Updated README on how to use GPG-encrypted files. Please try it and report

Kevin Purdy, editor at Lifehacker has an excellent post featuring setting up and configuring Snippits. Why not take a look? (Also, a birdie tells me there will be a new release of Snippits soon. Keep your eyes peeled. Peeled, like tangerines.)

I’ve been tweaking the design of the site for the past week or so, shifting elements around and mostly attempting to give the text a chance to breath. Because HTML sucks, my spring cleaning will undoubtedly broken something for someone, somewhere. So, if you are that someone, and you’ve noticed some bit over here broken, give me a ring, if you please, and let me know. Thanks. Oh, and I’m still not done, that sidebar over there is giving me trouble. Bear with me, please, I’m working on it. ­

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p>Today, in December 2007, of the 6.6 billion people living on our planet, around three billion have access to cellular service (1).  In contrast to the relatively staid growth of fixed telephone lines (fig. 1), the growth in cellphone and Internet service subscribers is staggering.  This growth is evident not only in the United States and Europe, it can also be seen in second- and third-world countries such as China, India, those in Africa (2), and those in the Arab world.  Although these countries are not as wealthy as the US, and certainly not the center of technological developments and innovation, their governments are finding that cellular and Internet service are basic and vital infrastructure that their populations highly demand.  Almost half the population on Earth is connected somehow to a telecommunications network, either the Internet or the local cellular network.  Furthermore, this proportion is on a strict upward trend.

I’m a big fan of great films. I try to seek out and watch those great movies that awe and inspire, that are beautiful and tragic, and those that are a work of art. And after I’ve seen them, I like to rate these movies, look for similar movies to watch, and give and receive recommendations. After searching low and high on the Internet for a site that would let me do this, I passed up several (IMDB, Flixster, and Rotten Tomatoes) I found one: Criticker.com.

Whew, what a day.  It’s 9PM here in Reno, and I’ve got the first shift on the floor.  One hour ago, the challenge overseers invited all the reporters and conference attendees into the exhibit hall, projected a large countdown, and waved a flag, all to culminate in…our team captain pressing a return key.  My roles for the challenge are POVRay (more below) and visualization, so our large TV immediately springs into life, green progress bars jumping and flashing.  Screenshots are below.

Update:  10:30 PM:

So, a bit about our configuration: we are running a 13-node cluster, with each node containing 2 quad core Intel Xeon’s, each core clocked at 1.86 GHz.  Each node is connected to the network with both a gigabit Ethernet connection, and a 5Gbps Infiniband link.  There is one hard disk located on the head node, for use by the entire cluster.  Data from the applications is first written to a 8GB RAMDisk shared over NFS.  Our cluster has a theoretical computing power of 750 Gigaflops, or 750 billion floating point operations per second.  For the contest, we are limited to 26 Amps total for the power, split over two 13-Amp circuits.  Power is distributed to 2 monitoring PDUs (Power Distribution Units), and if we go over the 13-Amp limit, alarms go off and we get emails.  We currently idle at around 8.1 Amps, and we are at 12.5 at full load.  I’ll be able to post some more pictures of the configuration, and the conference floor, after I get back to the hotel tomorrow morning.

Update: 11 PM: 

The contest is structured in two parts: a benchmark and a application and data set computing challenge.  We are just now finishing up with the HPCC benchmark suite, and after that, I’ll begin the POVRay jobs, rendering either pollen particles, SQUIDAtom (not sure, it’s the last image, below), or any other strange number of things.  Our two other applications are POP, to simulate ocean temperatures and curents, and GAMESS, which does crazy molecule and atomic simulations.  We have 25 separate datasets over these 3 applications, and each data set is worth some number of points.  Points are also awarded for the HPCC benchmark.  At the end, the teams with the most points wins!

 

Update: 11:45 PM:

I’ve finished rendering Pollen6, a nifty simulation of what looks like the most painful pollen particle I’ve ever seen.  I’m rendering the SQUID data set now.  After that, I’ll try what is labelled Scene005, which I believe is a rendering of microbial activity.  The next shift comes in at 6AM,  at which point I’ll grab a cab back to the hotel, although there are some inviting leather couches nearby.

 

­

So, the cruise kinda sucked.  First, our bus broke down, then it started raining, and finally, the boat (The Mason Dixie II) wasn’t that impressive.  The food was good, but we had to endure "entertainment" by a fake Sam Clemens a.k.a Mark Twain.  The jokes were not funny.

On the plus side, we got our cluster up and running, and I was even able to run POVRay yesterday.  So far, we don’t have any problems fitting under the power limit.

We also get a couple of perks: since the conference organizers weren’t able to secure prepaid Visa cards for us, we get an envelope of cash every morning.  There is a party for all the Cluster Challenge participants Wednesday night, featuring a performance by The Blue Man Group.  We get extra points because we have Intel processors.

We also have two very tall Stony Brook Banners, a table for our TV, small stuffed mascots, and other schwag.  Our booth space is looking professional.  The other teams seem to be doing well.  Most have half-height racks instead of full-height, and the IU + Apple team has very nice-looking equipment.  I maintain that we have a good chance of coming out ahead.  Watch this space.

So I’m typing this from the back room in the Reno-Sparks Convention Center in Nevada. We’re almost done setting up our full-height rack with all our computing nodes. We’re hooking up the 5 Gbps Infiniband as I type. After we’ve got the hardware all set up, we still have a bunch to do on the software side of things.

The other teams are arriving now also. The Taiwanese team is already here, they are just waiting for their rack. The Purdue team has shipping containers strewn about, but their team isn’t here yet. Same with the Indiana University team - their Apple hardware is just sitting there, some eight or 10 XServes, plus a paltry 23-inch Cinema Display. Our Plasma TV is 42 inches, and it’ll be displaying all our progress, as well as the slickest screensavers I can find.

After that, we have a all-hands meeting to go after safety procedures, and tonight, when everything is ready, all the teams are going on a chilly late-evening dinner cruise on Lake Tahoe. It sounds pretty fun, I’ll tell you about in my next post.