Mare Nostrum Europe most powerfull supercomputer

The Europe most powerfull computer has been build by IBM, it will work with Linux operating system and will count with 4.564 processors with Power technology. It will be used to medical investigations like human genome, proteins, medicaments development and climate change.

More information (in spanish)
Barcelona Supercomputing Center http://www.bsc.org.es/
IBM: http://www.ibm.com/news/es/2004/11/superordenador.html
(in english)
http://imagicweb.com/ambient/modules.php?op=modload&name=News&file=article&sid=66

Backup and restore floppy disks and drives with Linux

We use still some floppies and it is important that we back up them, because it is a long process to create the disk and if it fails, the time to redo the disk is longer than restoring a backup or the knowhow is not there.

To backup a floppy disk or any other disk we use the dd tool, including hard disks, in new versions of Linux it supports files larger than 2 Gigas.

$ dd if=/dev/fd0 of=/backup/floppy_backup.dd

To restore the backup into a fresh floppy (note, you will loose any other information in the floppy):
$ dd if=/backup/floppy_backup.dd of=/dev/fd0

Let me know what did you backed up !

Set the keyboard language in Console and XFree86

To set the keyboard keys distribution (or language) use these utilities:

$ setxkbmap
$ setxkbmap us
$ setxkbmap es
$ setxkbmap us-acentos

Adding and quiting services with chkconfig

This implementation of chkconfig was inspired by the chkconfig command present in the IRIX operating system. Rather than maintaining configuation information outside of the /etc/rc[0-6].d hierarchy, however, this version directly manages the symlinks in /etc/rc[0-6].d.

In Redhat Linux you have a powerfull tool called chkconfig, you can list all the services with:
chkconfig --list
To see the services started in runlevel 3:
chkconfig --list | grep 3:on

To turn off a service in all the runlevels:
chkconfig pcmcia off

Turn off a service in a desired runlevel:
[root@monitor1]# chkconfig --list | grep hpoj
hpoj 0:off 1:off 2:on 3:on 4:on 5:on 6:off
[root@monitor1]# chkconfig --level 3 hpoj off
[root@monitor1 rc3.d]# chkconfig --list | grep hpoj
hpoj 0:off 1:off 2:on 3:off 4:on 5:on 6:off


If you want to add a new service, you created the /etc/rc.d/init.d/ file and now you wans to manage the service, configure it to start and stop on desired runlevels.

Edit the /etc/rc.d/init.d/service-name file, and add this line on the top:

#!/bin/bash
# chkconfig: 2345 55 25
# description: A service that does powerful things
#

This is a description of what this line does:
# chkconfig: 2345 55 25
             |   |  |
             |   |  priority for kill scripts
             |   |
             |   priority for start scripts
             |
             run levels at which to start service

Then execute, for example, adding the qmail service:
[root@monitor1 init.d]# chkconfig --add qmail
[root@monitor1 init.d]# chkconfig --list qmail
qmail           0:off   1:off   2:off   3:on    4:off   5:on    6:off

Now configure it to start on desired runlevels !