Question 1:

Computer network:

A computer network is a group of computer systems and other computing hardware apparatus that are connected together through communication channels to facilitate connection and resource-sharing among a broad range of users. Systems are routinely categorized founded on their characteristics.
One example for a computer network was a network of communicating computers that functioned as part of the U.S. military's Semi-Automatic Ground natural environment (SAGE) radar system. In 1969, the University of California at Los Angeles, the Stanford Research organisation, the University of California at Santa Barbara and the University of Utah were attached as part of the advanced study tasks bureau Network (ARPANET) task. It is this network that developed to become what we now call the Internet. Systems are used for the following key causes: To facilitate connection via internet message, video conferencing, instant messaging, etc. To enable multiple users to share a lone hardware device like a copier or scanner To endow document sharing across the network To permit for the distributing of software or functioning programs on remote systems To make data easier to get access to and sustain amidst network users .( R. Morris (10-2001))

Personal area networks (PANs);
A Personal area network - PAN - is a computer network coordinated round a one-by-one individual. Personal area systems typically involve a mobile computer, a teli phone and/or a handheld computing apparatus such as a PDA. You can use these networks to transfer documents encompassing internet message and calendar appointments, digital photographs and music.
Personal area systems can be assembled with cables or be wireless. USB and FireWire technologies often link simultaneously a connected PAN; while wireless PANs normally use Bluetooth or occasionally infrared attachments. Bluetooth