Networks are everywhere in the world of business. A network is a series of computers throughout the company which rely on one or two fileservers. Or it can be used in long distance communication through modem. An example would be that a company located in Calgary can call up its other branch in Toronto via modem, also able to up and download valuable files or records. Networks have their disadvantages also.
Computer viruses are always present somewhere in a disk or computer system ready to strike.
If an over powering, destructive virus enters a network system, all data can be severely damaged or lost completely. That's why there is back-up drives to store existing data that is written onto the disk each day. Anti virus programs are there to alert the user and wipe the virus off the system before it does any destruction to the data stored on the network. As far as practicality and mobility is concerned, the laptop has been around for quite a long time. A laptop computer is a portable computer, about the size of a brief case.