Any software program, no mater how complex, can be written as a combination of these three boolean operators: AND
, OR
, and NOT
.
And it just so happens that these operators have physical counterparts known as logic gates. These logic gates are in fact exactly how some micro processors work.
From this, we see that the previous answers given here by other people are actually correct: a physical computer can be thought of as the antonym of a virtual machine.
However, let's not stop at this simple answer. Let's take this knowledge further.
Since any program can be represented by the AND, OR, and NOT operators; and since these software building-blocks have physical counterparts; we can therefore say that it is possible to make a physical circuit with all the functionality of a given computer program.
And since a "virtual machine" is nothing more than a sophisticated program, it too can be modeled by an electric circuit — albeit a very big and unreasonably-expensive circuit.
In colloquial terms, one may suitably refer to such a circuit this as a "hardwired program".
This terminology bears allusion to devices like the [hardwired controlled unit][3] which, in the past, were used as faster alternatives to microprogrammed devices.
In short, we can say that a "hardwired program" is an electronic circuit which performs a particular function not by interpreting software instructions, but rather by being an exact physical representation of the software itself.
Essentially, it's a piece of hardware "pretending to be" a piece of software. :P
Some Notes:
Besides the improved performance, such hardwired devices can have improved security and reliability, which are important in some high-grade applications. For example in reliably generating a normal distribution of random numbers — which is, by the way, a more difficult problem than it may seem.
It's also worth mentioning that very early video games were actually implemented directly into the hardware due to the performance benefits that this provided.