How to install 12.04 on a pendrive?

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http://askubuntu.com – All I want to do is, install ubuntu onto a pendrive, so that I don't need to use my internal HDD. Another motto is to install packages on Ubuntu, in pendrive(so I don't want to use the 'live pendrive' thing) I installed it on the pendrive, and selected the boot installation to dev/sdd1. But when I boot the pendrive, it says 'Missing Operating System' Also, one more question, can the same pendrive be booted on any other computer? (HowTos)