Tiny-Core is a Linux the runs completely from RAM. I use it for maintanance, you can boot it from USB and then remove the boot device :)
Get it from http://tinycorelinux.net/
Download the book, and the Tinycore ISO with gigantic 16MB. The Tinycore is with graphical interface. Core is cmdline only and a bit too hardcore for first time use.
When it runs, right click the desktop and choose Apps to install packages.
I boot it from USB with Syslinux, I could post a howto if needed.
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