Back when I worked on software validation of large clinical chemistry analyzers, I had a number of these that I could move around the lab and hook directly to the target machines.  We had an array of Turbo-C programs that would inject data into the machine over the serial port and read back results.<p>It was a lot easier to move these machines around that it was to move PC-ATs.  The battery also kept the machine running even if the power glitched (which we would test as well)