A couple of years ago it was not possible to boot from USB on every computer (where the BIOS doesn't support this). There was a tiny ISO image which allows for booting from a USB stick.
Now we have the same situation with software for virtual machines such as VMWare, Parallels Desktop and this ISO is useful again. I use Parallels Desktop 7 for Mac OS X which doesn't have an option to boot from USB or USB stick.
I have following real world situation: I have HDD with Linux installed. It is not like Live CD, it is already configured by me. I use it on my computer at work to boot environment I like and I use it at home to have same environment. Sometimes I work with Mac OS X and want to download something for my Linux (such as updates and new software) and configure something if I need.
I can't boot from it using Parallels Desktop or VMWare because BIOS in this VMs doesn't recognize my USB or it can't be attached before I run my VM.
Where can I find an ISO that would allow me to boot from a USB stick?