I have a company notebook with encrypted HDD. I cannot change anything and, as usual,is a windows xp2 system. The only way I can boot linux easily is running a USB pen installation. I use SLAX, it works pretty well, configurable, fast. The issue with USB pen is that is not a complete installation, it runs in memory and not all the distribution can be run from there. Plus all the limit of running an OS from a small memory.
While is possible to install a minimal version of ubuntu on a USB Pen, this is not recommended. First of all the Flash drive are not build to work with continuous read and write access, as required for a full installation of Ubuntu or any other distribution.
The best way is to install your Linux distribution on a 2.5″ USB HDD, it is cheap, fast, reliable and it is like to run your distribution from your PC HDD. How to do that is a less than 1 hour job, easy even for novice. I suggest to prepare the partition before to start any installation, though Ubuntu installer gives the opportunity to do it during the installation. I recommend to create at least 3 partition: one for the root, one for the swap and the third for some free space to share with windows.
Let’s start.
Prerequisite: In this guide I suppose that you have at least the knowledge on how to partition a hard disk, run a live linux distribution and in general how to use a Linux at basic. It is better to use a desktop where you can disconnect all the IDE or SATA drive.
1) Prepare your HDD. You can use the live CD of Ubuntu Edgy. Boot, connect the USB HDD, run gparted. Don’t forget to un-mount the HDD before doing change to the partition table.
2) On a 80GB HDD, I suggest 15GB ext3 for the Ubuntu system, 1GB for the swap file and the rest for a FAT32 partition.
3) Disconnect all your fixed HDD and boot the CD with the installation. Just leave connected the USB HDD.
4) During the Ubuntu installation, the system will ask for automatic or manual partitioning. Choose manual and put the mount point of the 15GB to the “/” (root). I suggest to use the alternate CD of Ubuntu that enable a text installation. Graphic installation is slower and a bit tricky during the partitioning phase.
5 ) Move on with the installation to the end.
6) Reboot from the Live CD and connect the USB HDD
7) You have to modify the menu.lst of Grub to reflect your notebook configuration. So, go on /boot/grub directory on the mounted external HDD (for instance /media/usbdisk/boot/grub/menu.lst) and, in case of my X41 change sda1 with sdb1.
8 ) Usually you have to modify also fstab in the external HDD installation to reflect the name of the mout point in your notebook. For Ubuntu edgy is not required any change because the drive in fstab are listed in a different way (I don’t know the details) and it works right as it is.
9) Now you are ready to boot your new OS from the external HDD. After booting, usually you will get a login prompt. This is because the Xorg configuration won’t match the new hardware in case, for instance, you have prepared the external HDD on a different computer. Dont’t panic!
10) Reconfigure the Xorg. On Ubuntu is pretty easy just execute:
user@host:~$sudo dpkg-reconfigure -phigh xserver-xorg
reply to all the questions, just use default if you don’t know. This is the most complicated step for some distribution. Be prepared, maybe read the xorg.conf generated when you run the live CD version before doing any change.
That’s it. Not really for newbie but reasonable simple for “less experienced” like me.
Just drop a comment if you need help. I will be happy to help you.
Posted by koenig 
