howto
Upgrading my laptop to ext4
Sunday, March 15th, 2009 | debian, english, howto | 3 Comments
Warning: Don’t upgrade root partition (/) or the partition in which /boot is placed unless you know what you are doing. More on this later.
Warning2: Make backups of your data.
Last Friday I went on upgrading to ext4 my laptop. I decided to go first with /home partition, as / has also /boot and can give some problems if not handled with care. Upgrading it is quite easy, and fast, as the old data is not upgraded, only new files will be added using new features.
First, I installed latest linux-image package to start using kernel version 2.6.28, which includes production ready ext4 support. After rebooting, I logged in as root so I could umount /home. The steps to upgrade are as follows:
# uname -a
Linux gimli 2.6.28-1-686 #1 SMP Mon Feb 23 03:13:24 UTC 2009 i686 GNU/Linux
# umount /home
# tune2fs -O extents,uninit_bg,dir_index /dev/home_partition
# fsck -pfD /dev/home_partition
# mount /home
You MUST run fsck. If not, ext4 won’t mount your filesystem, so don’t forgive this step if you’re upgrading your / partition. You will see some checksums errors appear. Don’t be afraid, that’s expected, and that’s why -p is added to fsck command, you it is not asking which action to perform in every error.
Upgrading partition containing /boot
For upgrading your / partition you have to take into account what grub and klibc version you have installed. The former is need so grub can read your kernel image from filesystem, and the second is needed due a bug that made initramfs detect ext4 filesystems as ext3, and passing incorrect option to mount, which failed. Versions in Debian known to work are libklibc >=1.5.15-1 and grub2 (packaged as grub-pc). Make sure you have these versions installed before trying to go to ext4.
Also, as you have to upgrade having your partition unmounted, you will have to get a console before root partition is mounted. You can do that by passing mount=break break=mount to your boot options in grub.
ENJOY!
Innovation in netbooks
Wednesday, March 4th, 2009 | english, gadgets, howto | 3 Comments
After the release of Asus Eee PC and the discovery of the market that was eager to buy cheap and “wearable” computers every laptop manufacturer has jumped into the hype and released their own versions of netbooks, with different success.
But somehow it was a cloning phase. Vendors were just cloning what Asus did, with more or less changes, but without innovating. Now, it seems that the path has opened again, from the open source and open hardware front, and it has been released AlwaysInnovating’s touchbook. It is a netbook with a detachable keyboard (it is even sold separated) and built upon an ARM processor from Texas Instruments, and a 8GB microSD card. Thus they claim the battery last from 10 to 15h with the keyboard, and 3 to 5h in touchscreen mode.
As is said above, the whole machine is open source based. Software is based upon OpenEmbedded, and hardware schematics of the board are released under GPL on Beagleboard project. They say that you can also install Ubuntu, Android or even Windows CE on it.
Update: Just discovered that AlwaysInnovating is a Grégoire Gentil startup. Grégory is a Civil Engineer from École des ponts et Chaussées. We know how to build things 
Speed up multiple SSH connections to same server
Wednesday, January 14th, 2009 | english, howto | Comments Off
I am copying here the tip I read in Linux Journal so I won’t need to google for it when needed. It works by multiplexing connections to the same server in the same TCP connection. For this to work, it needs a socket to track each connection.
You have to add these lines to ~/.ssh/config file:
Host *
ControlMaster auto
ControlPath ~/.ssh/master-%r@%h:%p
Postfix+TLS+SASL in Debian HowTo recovered
Tuesday, January 13th, 2009 | debian, english, howto | Comments Off
Once of the most visited pages in my site was the Postfix+SASL+TLS for Debian Sid and Sarge Howto, who I wrote 3 years ago. As I hosted it in my old home server, when it broke it went offline, and though there are still some copies around the net, there are a lot of referals still directing traffic to tribulaciones.org.
Now I have recovered it and it is now available again. I will write an .htaccess file to redirect people to the new place and, with some more time, I will review it to see if there are some changes needed for Lenny.
Enjoy!
UPDATED 14/01/2009: I have added promised .htaccess file, so every link to old URL (http://www.tribulaciones.org/docs/postfix-sasl-tls-howto.html) will work again.
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