- The letters PC after someone's name mean they are a member of the Privy Council
Today, most PCs usually have a basic set of software called an operating system. The most popular operating system on PCs is Windows, sold by Microsoft Corporation. PCs made by a company called Apple Inc. can use a different system of software called Mac OS that is sold by Apple Inc.
Many free operating systems are available. They are called Linux operating systems. There are over 300 different Linux "distributions". Each one has a different purpose. For most people using Ubuntu-Linux is the best choice because it is the easiest to use.
The CPU (Central Processing unit) follows the instructions in the operating system and application programs. The memory, or RAM (random access memory), is for moving information (or data) quickly to and from the processor. The hard drive holds programs and data while the computer is powered off. Floppy drives, CD-ROM drives are used for storing information on removable disks.
Computers may be used for work, including doing research using the internet, keeping records; or writing documents. Other uses include communicating, with people across the world using Instant messaging, e-mail or Skype or recreation activity such as playing computer games.