Wikipedia
SoulPad is a mobile computing project developed by researchers at IBM. The project's aim is to provide a computer user with the ability to suspend their operating system environment and resume it on another computer, all by using a USB data storage device. The SoulPad project is the subject of a paper entitled Reincarnating PCs with Portable SoulPads, which won Best Paper at the 2005 ACM/ USENIX MobiSys conference. A video demo of the technology in action was made available on IBM's website.
The researchers of the project have suggested that SoulPad could be used to boot one's operating environment from USB compatible storage devices such as cell phones and iPods (the latter being used in the video demo of the project).
The name SoulPad is derived from the project's aim to separate the underlying computer hardware (the "body" of the computer) from the user's operating environment (the "soul" of the computer). The "Pad" part is most likely a reference to IBM's former ThinkPad line of laptop computers.