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
http://www.strw.leidenuniv.nl/local/computers/it_local/).
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 http://www.ittvis.com/idl/idl7.asp.
- 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".