A computer's hardware components are the parts you can touch. Computer hardware is the physical part of the computer. The smallest hardware component that can still perform computations is the computer chip. A computer chip is composed of semi-conductors and tiny wires laid out on top of thin wafers of silicon. Layers of wire and semi-conductors sandwiched between layers of silicon comprise a computer chip. The semi-conductors can be configured to represent either a 0 or a 1 when electricity is supplied to them. The configuration of most computer chips cannot be changed once they are built and most kinds of hardware are thus said to be 'hard-wired'.