Can you boot from any external HDD?

Question

I am going on vacation and I am taking my corporate Win7 laptop along. To keep personal and private data separate, I'd like to have two OS installs, but I don't want to dual-boot from the laptop HDD. So I intend to install Ubuntu on an external HDD and boot from there.

I was on Amazon shopping for an external HDD specifically for this purpose, when a user comment caught my eye. The user claimed that the HDD I am looking at is not bootable, as it has two disks internally and this configuration is readable by modern OSs (thus making a good storage medium), but not by the typical BIOS. He claimed that he has tested the 120 GB version of the same HDD and it would boot without problems, because it is a single-disk, but the 250 GB one won't.

Is this true? Can you boot from a two-disk HDD or not? And if not, how do I recognize whether a given HDD is a two-disk or single-disk type? (No it isn't in the data sheet, I looked there :( )

Answer 1

Booting solely depends on your BIOS. Older BIOSs can't handle disks larger than 32GB or USB disks at all. And they also have bugs.

If your laptop is less than two years old, it should work, especially if you make the boot partition for your OS the first on the external disk.

If in doubt, buy the disk at a local store (even if it costs $20 more) and ask that you can try it.