The Computer is the procedure that is the instantiation of the Abstract Machine and is the ideally stated method - a set of on and offs. A computer may be defined the Von Neumann architecture that may be considered the ordered procedure and is now networked. 'Computer' is not in fact mechanical and is the formal table of instructions and is a series of switches. The formal approach is defined the Abstract Machine that may be taken as the formalized modus operandi.
'Computer' is not fundamentally machinery and is the formal method that can be made in many ways.
See also Inscription,