Fenimore thinks this is a cool thing to do, run Linux from a flash drive, from anyone’s computer. These are my notes on how to do this.
Most computers can boot from a usb drive, but the commands vary. For several machines, f12 during the boot brings up a boot device menu. For other computers, this may be f9 or another key, usually identified by the computer during the early boot screens. In some older computers, you may have to change the bios settings to allow booting from a usb device.
How do you create the bootable flash drive? This is not difficult if you download the free utility Unetbootin. Unetbootin runs on both Windows and Linux.
I haven’t used the Windows version yet. For the Linux version, you can install from an .rpm or .deb file, or download an executable file. (For the latter option, you have to change permissions to permit the file to be run as an executable).
To install Ubuntu on a USB drive, you download the ISO image of the version you want to install, and run Unetbootin. (Unetbootin can even do the download for you). The menus are very straightforward, and it works with flash drives or usb connected hard drives. This makes it easy to download and test different Linux distributions, without having to change a single bit on the main hard drive of computer you use to run the program.
I have not had much luck making an Apple computer boot from a usb device.
A flash drive of 1 gigabyte or larger will work fine. It boots, runs and shuts down surprisingly fast from a flash drive. I have been impressed at how well a flash drive version of Ubuntu 8.10 can boot from many different computers, and find and use properly the video card, sound system, wireless connections, and use the computer’s drives and even bluetooth devices. A default Ubuntu install comes with a lot of software to begin with, including open office, Firefox and many other programs. You can upgrade and install new software, and keep your settings, and store whatever documents you like, depending upon the size of the flash drive.
One important use of a bootable flash drive is data recovery. You can boot up a computer from the flash drive, and also read the normal hard drive data. I have used this to copy data files from a disk that has too many errors (or viruses) to boot directly from its own internal hard drive.
Another use for a bootable flash drive is to bypass some of network security features that normally would make it hard to use a computer or access the Internet. There are times this will come in handy.
UPDATE
There are issues concerning the “persistence” of the data stored on the flash drive. In the default Unetbootin install of a Ubuntu “Live” drive, stored files are wiped out when you power down. You can fix this by tweaking some of the Grub options. However, an easier method is to create a drive using the Ubuntu 8.10 utility, usb-creator, which you can find on the Ubuntu System/Administration menu. This utility is present in the Ubuntu 8.10 live distribution, so you can use Unetbootin to create a bootable flash drive with Ubunut 8.10, and then use the bootable flash drive to create one that allows you to store data. One would think that Unetbootin should include this feature at some point.