Practically every Linux distribution, including my favorite Ubuntu, can be downloaded as an ISO image. Traditionally these ISO images are then burned to a CD recordable or a DVD recordable. When that is done, you load the CD-R in the optical disc drive of the PC on which you want to install the Linux distribution and you restart the PC. The optical disc drive is then used as a boot device, and the Linux distribution can then be installed. In Ubuntu’s case, the installation is started after Ubuntu itself is started, because Ubuntu is a Live CD in case you download the Desktop CD version.
These times USB flash drives are quite popular, and they have some advantages compared to CD’s and DVD’s. The most important advantage in my opinion is that USB flash drives are reusable while CD and DVD recordables are not. Other advantages are portability, performance, reliability and ruggedness. I often have to throw away CD recordables which contain old versions of Ubuntu, I’d like to avoid wasting CD’s. Fortunately, it’s also possible to use USB flash drives for installing Linux distributions.
I have found instructions on the Internet. Because Ubuntu’s ISO image is supposed to fit on a CD it’s file size is approximately 700 MB, so you need a USB flash drive which has a capacity of at least 1 GB. If you are using Windows, follow these instructions. If you are already using Linux, follow these instructions on the Ubuntu Wiki and use the script. These instructions are very easy to follow. But I’ve experienced that these instructions fail to mention an important step, to be able to use the USB flash drive as a boot device I had to change a setting in the BIOS of all three PC’s on which I have booted from a USB flash drive.
You need to set the USB flash drive as the first hard disk drive which is going to be used as the boot device. By default the USB flash drive is set to be the boot device after the hard disk drive(s), and then it will not work because the PC will boot from the hard disk drive. There are several different BIOS manufacturers and the way to do this is depends on which BIOS is used by the PC. On the PC’s I have tested, I have encountered two different BIOS versions, one computer had an Asus A8N-E motherboard which used a BIOS produced by Phoenix Technologies (Award BIOS), the other two computers used motherboards manufactured by MSI and used a BIOS produced by American Megatrends (AMI BIOS).
To access the BIOS, you need to press the Delete key soon after starting up the PC. In the AwardBIOS you need to go to the “Boot” menu, then choose “Hard disk drives”. Then you should see the name of the USB flash drive below the hard disk drives in a numbered list. You need to place the USB flash drive on the top of the list with the “+” key, and then press F10 to save the change and exit the BIOS. In the AMIBIOS you need to choose “Advanced BIOS Features”, “Boot Sequence”, “Hard Disk Drives”.
After I had followed these steps, everything worked perfectly. Unfortunately, this information isn’t found on Ubuntu’s website, but on other websites. The instructionson the Ubuntu Wiki don’t count, because those are “hidden”, i.e. you won’t find them unless you search for them well, this way the average user will never find them unless they are on the Ubuntu.com website. Notice that when you choose the links “Get Ubuntu” and then “Download Ubuntu” on the website, you will arrive at this page after choosing a download server? Here you can find links to pages explaining how you can verify the MD5 sum and how to burn the ISO image to a CD recordable. Exactly this page should also contain a link to a page explaining how to install Ubuntu from a USB flash drive, instructions for doing so should be made more accessible to users. Even if the instructions I linked to are relatively easy, some people which lack knowledge might be put off by it’s seeming complexity. Perhaps an application with a graphical user interface could be created, which would enable the user to select an ISO image and a USB flash drive, and which would then automatically copy the files to the USB flash drive.