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The newsletter of the SIE de Investigación y Enseñanza N. 39 - December-2010 / January-2011
To err is human - and to blame it on a computer [or on the SIC/SIE staff] is even more so.

Updates to Fedora 12

In the next two or three months all desktop PCs will be upgraded to Fedora 12. A dozen users have volunteered to be our "guinea pigs", or, more elegantly, "beta testers", and helped us find out and fix those minor problems and inconsistencies that typically show up after such a big upgrade of the Operating System. There is an important change with respect to previous RedHat/Fedora installations: now all software packages are installed locally on the machine's hard disk (no longer on a central server), which will make loading programs faster. The complete Fedora 12 + local software will take about 140GB, a generous figure meant to allow for painless (no disk repartioning) future OS and software updates. Upgrading a PC will take a few hours, depending on how much data in the /scratch disk(s) must be first transferred to a temporary storage area and then copied back after the upgrade is completed.

New Web servers

As you may have already noticed, some of the Research Area internal websites have moved to a new server, managed by the SIE. The homepage for the research area intranet is now http://venus/inves/, the SIE wiki is at http://venus/SIE/wiki/, while the forum is at http://venus/SIE/forum/. In short, the new server is "venus", a name chosen because it's very easy to write and remember, it's spelled the same in english and spanish, and suits better a webserver who has astrophysicists as its main clients. The Research Area external websites is also being migrated to a new webserver, managed by the SIE, with the aim of relieving the SIC's workload (the SIC staff will be very busy managing and providing support for the IAC-gestion project), and of specializing the server configuration and installed software for such applications as the Virtual Observatory, Fortran or Python-coded tools, PHP-based websites, etc. This will be a slower, more careful process, and more details and status reports will be given in due time.

New printers

Several printers have been bought last year, and are already installed and available to all users. A brand new color printer for the A3 format is now located at the end of 2nd corridor, ground floor (next to the Research Area Secretariat). Its name is lwinv2 (ip: 161.72.202.191). Please use it only for work-related jobs (it was kind of disappointing to discover that the first color printout to ever come out of that printer was a list of traffic violations and corresponding point penalties - we can only hope the user who did it will drive more carefully now ...). Four new B/W printers have replaced older models that had reached the end of their life cycle: lw3, lw19, lw20, lw21 (you cannot fail to notice them ...).

Condor/Diodo/LaPalma Hall of Fame

As we do every six months, it's the time to publish the usage statistics of the Supercomputing resources at the IAC for the second semester of 2010. In total, 814768.9 CPU hours were delivered during this period. By resource, Condor delivered 577898.8 CPU hours, LaPalma 218551.43 and Diodo 18318.67. Full details of the breakdown by users can be found at the SIE Forum for  Condor, LaPalma and Diodo. If you want a piece of this pie and don't know how to start, just let us know.

Mathematica through ssh tunnel

In case you want to use Mathematica at home, it is quite simple. At the IAC the licence server for Mathematica listens on port 16286, so if you have a PC with Mathematica installed locally (but without a license), to access that license server you just need to:
  • locate the "mathpass" file in the PC and add the line:
    !localhost
  • then create a ssh tunnel where the local 16286 port is redirected to the 16286 port in the license server ("pampero").
And that's all. Now Mathematica at home works fine, but using the Mathematica licenses at the IAC. If you don't remember how to create ssh tunnels, this SIEPedia article has all (and more) the details.

Gigabytes and Gibibytes

As part of the "guinea pigs" who are testing the installation of Fedora 12 in a desktop machine, I've received a brand new Dell PC with a 500GB hard disk. However, when I check the available space with df -h, I notice that the disk has apparently shrunk to 465GB. Where have the 35 missing GB gone? Is Dell cheating when claiming that the disk is 500GB? Has partitioning the disk eaten them away? It actually turns out that the disk is both 500 Gigabytes and 465 Gibibytes in size. Kilobytes, Megabytes, and Gigabytes are power of tens (SI units - so 1 Gigabyte is 1,000,000,000 bytes), while Kibibytes, Mebibytes and Gibibytes are binary units with a step of 2^10=1024 (so 1 Gibibyte is 1024x1024x1024=1,073,741,824 bytes). As you have probably already figured out, df -h displays the results in binary units, and you must use df -H to get the SI units (unfortunately, df displays the same suffix, G, in both cases, adding to the confusion). A more detailed discussion about binary units can be found in the Wikipedia entry on Binary Prefix.
SIE de Investigación y Enseñanza :: N. 39 - December-2010 / January-2011 - Contact: