Chasing the Clouds Home

The Korn shell uses two startup files, the .profile and the .kshrc. The .profile is read once, by your login ksh, while the .kshrc is read by each new ksh.

Wondering how the new quad-core Intel Nehalem (Xeon 5500 series) and six-Core AMD Istanbul (Opteron 2400 series) stack up against each other on HPC-style codes? The folks at Advanced Clustering Technologies, a company that builds customized HPC clusters from standard components, have been putting the latest high-end x86 silicon through its paces, and have generated some interesting results.

Those of you who don’t have perfect children will find this familiar: Just as I was withdrawing money in a bank lobby, my 5-year-old daughter chose to throw a temper tantrum, screaming and writhing on the floor while a couple of elderly ladies looked on in disgust. (Their children, apparently, had been perfect.) I gave Dorothy a disappointed look and said, “That argument won’t work, sweetheart. It isn’t pathetic enough.”

Select your state from the list on the right to see how it compares internationally. The graph shows how your state’s average mathematics score compares to each country that participated in the 2007 Third International Mathematics and Science Study (TIMSS).

Change UID/GID for a user from the command line in Leopard.

Leopard's Accounts Preference Pane also hides a set of advanced options you can use to customize user account settings. To get at the advanced options, Control-click a name in the Accounts Preference Pane, and then choose Advanced from the pop-up menu.

What environment variables are available in Windows?

Supporting Multiple Repository Access Methods

So how do you learn parallel programming? Luckily there are a number of resources on the web. Here are just a few links

what is this thing /dev/dm-[0-6] ?

Bootstrap is a simple but powerful Monte Carlo method to assess statistical accuracy or to estimate distribution from sample's statistics.

In this paper, we show how to leverage largely commodity Ethernet switches to support the full aggregate bandwidth of clusters consisting of tens of thousands of elements. Similar to how clusters of commodity computers have largely replaced more specialized SMPs and MPPs, we argue that appropriately architected and interconnected commodity switches may deliver more performance at less cost than available from today’s higher-end solutions. Our approach requires no modifications to the end host network interface, operating system, or applications; critically, it is fully backward compatible with Ethernet, IP, and TCP.

Oracle RAC over InfiniBand

This site is a companion to the influential computer-science text Structure and Interpretation of Computer Programs, by Abelson, Sussman, and Sussman. Its purpose is to demonstrate the Web's potential to be a channel for innovative support for textbook users.

I recently came up with what I think is an intuitive way to explain Bayes’ Theorem. I searched in google for a while and could not find any article that explains it in this particular way.

“Everything You Ever Really Needed to Know About Personal Finance on Just One Page” is a 49 page personal finance book that weaves together most of my favorite ideas on personal finance and a lot of other goodies into one document. I’m making it available for download under the Creative Commons Attribution-Share Alike 3.0 United States License, which means that this document is free - you can send it to your friends, put it up on your website, or print it out.

Processing is an open source programming language and environment for people who want to program images, animation, and interactions. It is used by students, artists, designers, researchers, and hobbyists for learning, prototyping, and production. It is created to teach fundamentals of computer programming within a visual context and to serve as a software sketchbook and professional production tool. Processing is an alternative to proprietary software tools in the same domain.

"Personal finance has come to substitute for the role government should play for people," observes Nan Mooney, author of (Not) Keeping Up with Our Parents. "In the past 20 years the myth of the person succeeding on their own has gotten bigger and bigger. This myth is dangerous. It tells you if you can't balance everything and you are in debt, it is your fault."

Article from Cory Doctorow about IT policies and procedures.

I've just had a quick article on the wars between corporate IT and tech enthusiast employees published in the Harvard Business Review. I've been on both sides of that barricade, and while I understand the plight of IT, I think that it's against everyone's interest to give them to power to lock employees out of figuring out better ways of using their PCs and the Internet to get the job done.

Whether you are interested in picking up CSS to create your own website, or merely to tweak your blog’s look and feel a little - it’s always good to start with the fundamentals to gain a stronger foundation. Let’s take a look at some CSS Tips we thought might be useful for beginners.

SL is a Linux release put together by Fermilab, CERN, and various other labs and universities around the world. Its primary purpose is to reduce duplicated effort of the labs, and to have a common install base for the various experimenters. The base SL distribution is basically Enterprise Linux, recompiled from source.

Structural Biology Grid (SBGrid) is a computing collaboration of several X-ray crystallography, NMR and electron microscopy laboratories. Participating laboratories include groups primarily at Harvard Medical School, Harvard University and Yale Medical School, but our alumni often remain members after becoming principal investigators at other institutions.

The example programs shown below employ the SPMD paradigm, i.e., an identical copy of the same program is used for each of the processes. Examples for the less frequently used MPMD paradigm (in which more than one program are used among the processes) are demonstrated in a separate page.

The goal of this tutorial is to teach those unfamiliar with MPI how to develop and run parallel programs according to the MPI standard. The primary topics that are presented focus on those which are the most useful for new MPI programmers. The tutorial begins with an introduction, background, and basic information for getting started with MPI. This is followed by a detailed look at the MPI routines that are most useful for new MPI programmers, including MPI Environment Management, Point-to-Point Communications, and Collective Communications routines. Numerous examples in both C and Fortran are provided, as well as a lab exercise.

The GM of the New York Yankees may be the worst ever at the best job in the world. Which is why he’ll inevitably fail this year in his shameless attempt to buy a World Series.

After I installed emacs I was horrified by its unbearable look which I thought would have changed over the few last years since I last tried it. Luckily the CVS version of emacs has considerable improvements in that area, it looks much better and I've been using it for few days and it seems to be pretty stable.

Recently i purchased Canon PowerShot S3-IS. Its a good camera but lacks raw picture format support in it. But now i find a way to get the raw support in my camera. CHDK Firmware is now available for some Canon P&S digital cameras. This firmware hack supports the following features:

If you have a point-and-click digital camera made by Canon, you may be able to turn on all sorts of features usually reserved for more expensive SLRs. That includes live histograms, depth-of-field calculation, under and overexposure highlighting, and -- best of all -- shooting your pictures in RAW. The secret is CHDK, an enhanced, free software replacement firmware.

In this post we present useful photographic techniques, tutorials and resources for various kinds of photography. You’ll learn how to set up the perfect environment and what techniques, principles and rules of thumbs you should consider when shooting your next perfect photo. This round-up isn’t supposed to be the ultimate one – please feel free to suggest more useful articles in the comments to this post.

There are several important decisions for organizations preparing to migrate from Network Information Service (NIS) or NIS+ to Lightweight Directory Access Protocol (LDAP). Similar yet simpler challenges are experienced by organizations that are embracing LDAP as a naming service for the first time.

I spent a fair amount of time debugging a bizarre net-snmp issue yesterday, and learned a TON about how net-snmp is implemented. While reading through the net-snmp code, I came across a number of macros similar to the following: DEBUGMSGTL((”mibII/udpScalar”, “Initialising UDP scalar group\n”)); The first argument to the DEBUGMSGCTL() macros contains a token name, which can be passed to the snmpd daemon’s “-D” option to get verbose debugging data

The problem? Not only is there no indication that any crime was committed, the investigating officer argued that the computer expertise of the student itself supported a finding of probable cause to seize the student's property.