Digital – operating on numbers rather than measured physical quantities.


Operates at electronic speeds, much faster than would be possible for humans or any mechanical device (the slowest electronic computers were about 1,000 times as fast as was possible from an electro-mechanical device).


Performance of arithmetic and/or logical operations.

Automatic Sequencing

By means of some form of program, the machine automatically carries out a largely pre-determined sequence of operations.

Conditional Branching

The results of intermediate calculations can be used to change the course of later ones. It is this which gives the computer its power of decision making.

Stored Program

The operations to be performed are governed by a program which is stored internally in the computer along with the data. Apart from making programming much easier, this also allows the program itself to be altered in the course of execution and therefore allows the computer to solve the widest range of problems,

Self Programming

The power and effectiveness of the computer is greatly enhanced if its computing power can be used to assist in its own programming. The computer can be used to convert easily understood code into binary, thus simplifying the programmer's job.


The computer requires a means of taking in information (input) and of presenting the results of its work (output).