**Real Computers**

Computer theorists often refer to idealized analog computers as real computers (because they operate on the set of real numbers). Digital computers, by contrast, must first quantize the signal into a finite number of values, and so can only work with the rational number set (or, with an approximation of irrational numbers).

These idealized analog computers may *in theory* solve problems that are intractable on digital computers; however as mentioned, in reality, analog computers are far from attaining this ideal, largely because of noise minimization problems. *In theory*, ambient noise is limited by quantum noise (caused by the quantum movements of ions). Ambient noise may be severely reduced – but never to zero – by using cryogenically cooled parametric amplifiers. Moreover, given unlimited time and memory, the (ideal) digital computer may also solve real number problems.

Read more about this topic: Analog Computer

### Famous quotes containing the word real:

“The things of this world reveal their essential absurdity when they are put in the Venetian context. In the unreal realm of the canals, as in a Swiftian Lilliput, the *real* world, with its contrivances, appears as a vast folly.”

—Mary McCarthy (1912–1989)