A virtual instrument alone is nonsensical. Measuring a voltage or a current with a multimeter is much simpler, faster, and cheaper than using a virtual measurement environment. A dedicated instrument can perform more accurate and reliable measures than any virtual instrument. On the other hand, if a measurement is a combination of different data, if it has to be mathematically manipulated, or transmitted, or recorded, or displayed . . .for these situations, virtual instruments prove their worth. The concept can extend to virtual controllers. A hardware controller can easily implement a single PID control loop, but virtual devices are much more flexible in implementing multiple control strategies. Virtual devices give the best results when solving complex measurement and control tasks. Let’s define the meaning of the two words that comprise virtual system.