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The newsletter of the SIE de Investigación y Enseñanza N. 26 - July/August 2008

SIEminar: "VO tools: An overview on Virtual Observatory tools", Thursday 17 July, 2008

The Virtual Observatory is an international initiative on standardizing astronomical data and protocols, as well as the development of scientific tools. Nowadays, the Virtual Observatory (VO) offers a number of powerful tools to manipulate and analyze catalogs, images, spectra and, of course, to interoperate with the Virtual Observatory archives. In the SIE, we resume our SIEminar series, short and technical seminars, like this one in which Jorge will present the most interesting tools the Virtual Observatory offers.

32bit vs 64bit CPUs and computing environments

About half of the PCs here in the Research and Graduate Studies Departments have a 64bit CPU. While virtually all astronomical software packages work exactly the same in 32bit and 64bit machines, nevertheless knowing the differences between the two architectures is especially important for advanced users or program developers. To help you understand in what aspects 32bit and 64bit CPUs differ, what kind of problems you might experience in a 64bit machine, and to write code fully compatible with both the 32bit and the 64bit computing environments, we have assembled this short and simple SIEPedia article.

Supercomputing support

The support on supercomputing will be temporarily discontinued at the end of July, as Angel's contract will expire in about one month, and he is taking his well deserved holidays starting July 28th. We hope that in about two, two and half months from now the supercomputing support position will be filled again. We regret to have been unable this year to keep a regular schedule for SIEminars, SIENews and software courses (as you certainly remember, the Web officer post remained vacant for a little more than three months), and we hope we can resume our activities at full speed when the SIE will be back to a stable three-strong staff.

Supercomputing hall of fames

As most of you probably know by now, the IAC has a number of Supercomputing resources that you can use. It is becoming our habit to regularly publish statistics of their use, so here there are the numbers for the first semester of 2008. In total, 888898.13 CPU hours were delivered during this period (roughly "equivalent" to 101.47 years in just one CPU). By resource, Chimera delivered 397901.20 CPUhours, Condor 331721.1 and LaPalma 159275.83. Full details of the breakdown by users can be found at the SIE Forum for Chimera, Condor and LaPalma.

Fedora and yum tips

Many Linux PCs in the Research and Graduate Studies Departements have recently been migrated to Fedora 8 as Operating System. Fedora 8 is a relatively new Linux distro, and has several, sometimes significant differences from the previous distro (Red Hat Enterprise Linux 4). We have found a few nice pages on Fedora 8 written by the Computer Support People at the Leiden Observatory: Fedora 8 issues, Fedora Core compatibility settings, Efficient use of the computers (the Home Page of the site is While geared to astronomers at Leiden, some comments and recommendations are of broader interest and may help you get acquainted faster with Fedora 8. As for Yum, it's a simple but powerful tool to install or upgrade packages (and all dependencies) in Fedora. Some of the most useful commands are:
  • yum list   # list of all installed packages
  • yum search <string>   # search for available packages having <string> in their name or description
  • yum install <package>   # install <package> and all dependencies
  • yum whatprovides <file>   # what package installed <file>?

Short announcements

  • IDL: v7.0 is now the default version (it includes the Workbench patch 7.0.3). For details about the IDL 7.0 release see
  • Burros (machines for massive data reduction): as in the last few months very few or no reservations have been made on rusco or esel, as of now access is free. esel has a 32bit CPU, 4 GB RAM and 420 GB of disk space; rusco has 64bit CPU, 4 GB RAM and 420 GB of disk space, plus an exabyte and a DAT unit. Both are located in the "Sala de Usuarios".
SIE de Investigación y Enseñanza :: N. 26 - July/August 2008 - Contact: