Dear All,
I want to install the full operating systems (SL 6, SL 5.5 and some variant of ubuntu), together with grub, on an external USB hard drive. This is so I can boot from the OS's, on different machines, whenever I need to. (A kind of portable operating sytems environment. For, I seem to have issues with LiveCD/DVD on usb sticks, especially on windoze machines, etc.)

Any things to watch out for in trying to install and use such an external USB hard drive?

I already learned the hard way, for multiple OS's, to use labelled disk partitions in /etc/fstab. More generally, how is hardware mapped or handled so that a given OS on the external drive *safely* boots/reboots from different machines [of the same architecture]?

Unfortunately, the only helpful sites I've found date back a long time, e.g.:
   http://www.brunel.ac.uk/~eesridr/extlinux.html
   http://ubuntuforums.org/showthread.php?t=80811
and so its not clear if one has to tinker with, say, mkinitrd in more recent OS versions.

Also, Troy's response in thread (Re: Only One Disk ??) is for installation USB's. (http://www.scientificlinux.org/distributions/6x/build/sites).

Any help appreciated.

Regards,

William.