Hello,
I have experience with installing to an external thumb drive, so I guess 
I'll reply.

It is easiest to start with a fresh install onto your external drive.
Boot up your machine with the installer, like you were going to install 
to your normal internal drive, but during the partitioning phase, leave 
the internal drive alone and only work with the external drive.
I always do the partitioning using the custom partitioning scheme 
because I don't want to trust it to the installer.
After partitioning, you come to the "Boot Loader Configuration"

https://fermilinux.fnal.gov/distribution/slf-5/installation/boot.loader.configuration.html

Click on "Configure advanced boot loader options" and click "Next"
At the advanced screen, click on "Change Drive Order"
On that screen, rearange the drive order so that your external drive is 
first in the list. Click "OK" Then double check to make sure that
"Master Boot Record (MBR)" is checked.
Then click "Next"

And then proceed like a normal install.

Then if your machine is able to boot off an external USB device, it 
should be able to boot off the external drive that you just installed on.

Troy

suhaiL khan wrote:
> Hello all
> Nobody responded to this mail. I also want to know this possibility.
> Any help is thankfully appreciated.
> 
> --- On *Tue, 25/5/10, Francis Ogula /<[log in to unmask]>/* wrote:
> 
> 
>     From: Francis Ogula <[log in to unmask]>
>     Subject: how can I boot sl54 from external hd?
>     To: [log in to unmask]
>     Date: Tuesday, 25 May, 2010, 3:07 PM
> 
>     Hello all, I have just installed SL54 on my  transcend external 235
>     GB hardrive.My internal hd has windows xp. However, My PC bios
>     cannot boot from USB. I installed grub to the mbr but it was unable
>     to boot either the linux or windows OS. I tried installing grub on
>     the external hd linux partition and attemped to boot it on a hp
>     laptop whose BIOS does support usb booting, but it only went as far
>     as GRUB_. Is it really possible to boot SL from an external HD? any
>     help will be appreciated 
> 
> 


-- 
__________________________________________________
Troy Dawson  [log in to unmask]  (630)840-6468
Fermilab  ComputingDivision/LSCS/CSI/USS Group
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