1. An operating system acts as an intermediary between hardware and software applications, managing computer resources like the CPU and peripheral devices while providing a user interface and executing services for other programs.
2. Common personal computer operating systems include Windows and Mac OS, with Windows being the most popular. Windows XP brought consumer and corporate versions together and improved the user interface, personalization, and security features.
3. Network operating systems handle network functions like sharing resources between computers on a network, providing data security and administrative control over the network.