Hey all, so I'm wondering how I can put an operating system on an external hard drive, and if i can boot it up on another computer. <-- in short.
Almost all versions of Linux, BSD, and other free *nix OSes can do it. ReactOS can theoretically do it in the future once USB support is all worked out. However, a requirement is that the computer's BIOS can boot from USB, which many cannot, at least not without BIOS flashing to the latest version.
All versions of Windows since the 3.x line, and Mac OS X cannot do it, and actively prevent installing to removable media.
Story:
My grandfather has a Vista computer (his Windows 98 fell to a flood in his house), and hates Vista. A lot of his programs that he needs won't work on Vista, and he doesn't want to re-buy the software for the prices. like Microsoft Office. So instead, I'm going to give him a "demo" of Windows XP. If he likes it, then I'll just re-format his Vista, and put XP on it. Or just swap hard drives. Is this possible?
The only way to get a "demo" of Windows is through http://www.nu2.nu/pebuilder/, but he won't be able to test out compatibility with applications as you cannot install applications in BartPE. Basically: far more hassle than it is worth. The only other option is to abuse Microsoft's http://www.microsoft.com/downloads/details.aspx?FamilyId=21EABB90-958F-4B64-B5F1-73D0A413C8EF&displaylang=en, though that "demo" too may prove too cumbersome.
Better solution: make Vista look like 98 through classic mode and use free alternatives for his applications (like OpenOffice.org). If he is retired, I can't see him having need for something like Access or the highest echelon of Excel macros