Computer networks are physical (equipment) and logical (program, protocol) structures that allow two or more computers to share their information with each other. Imagine a computer by itself, without being connected to any other computer: This machine will only have access to your information (present on your HDD) or information that may come to it via floppy disks and CDs. When a computer is connected to a computer network, it can have access to the information that comes to it and the information present on other computers connected to it on the same network, which allows much more information to be accessed through that computer..