Software that functions as a virtual sampler. It is a musical instrument that allows a user to load, edit, sequence, and play back audio samples at different times and pitches. Most professional software samplers have built in effects, both realtime and applied, and are able to interact with other audio software such as MIDI sequencers. This allows you to control a software sampler with a MIDI keyboard.
Soft samplers are a relatively new invention; only the latest computer hardware has enough CPU power to drive one with the extreme precision, fidelity, and timing required by a musician. They are growing rapidly in popularity as their reliability and speed increase. By being software, they gain all of the advantages of being on a computer: easy upgradeability, easy access to samples, plenty of storage space, a monitor, and keyboard and mouse input. They are also considerably cheaper than comparable hardware samplers.
Examples of some software samplers on the market today (Feb. 2001) are: Bitheadz Unity DS-1, Steinberg Reason, and to a lesser degree Steinberg Rebirth.