PS1 Emulator on a USB drive

Is it possible to run one of the PS1 emulators off a USB stick? if so, how? what would the file structure look like?

The file structure would be the same as if it were on an SD card.

As for USB support, I don' know....You'd just have to try it to see.

well its reads the USB stick for revolution.... but it freezes when it tries to start the game... any idea