Computers can be classified in various ways, including by purpose, size, and functionality. They can be general purpose computers designed to run many different programs, or specialized computers designed for a specific task. Computers also differ in how they process and represent data, operating as digital computers which use binary representations, analog computers which represent values as continuous quantities, or hybrid computers which combine aspects of both. Finally, computers are also classified by size from the largest and most powerful supercomputers down to palmtop computers.