The "operating system" of a computer is like a first, supervisory program that begins running when the computer first starts up .

The operating system plays an invisible administrative and bookkeeping role behind the scenes.

• The time and date are displayed on the system tray.
  
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• The system tray (or "systray") is a section of the taskbars in the Microsoft Windows operating system (OS) user interface that provides easy access icons to the user's most commonly used apps and displays the clock.
• A system tray is also available in other OSes such as Linux, Mac OS, Android, and iOS.
  

A computer network is a set of computers sharing resources located on or provided by network nodes.

The computers use common communication protocols over digital interconnections to communicate with each other.

A local area network  is a group of computers and associated devices that share a common communications line or wireless link to a server.

Modem is a combined device for modulation and demodulation, for example, between the digital data of a computer and the analogue signal of a phone line.

Hierarchical Schema. In hierarchical database model, the data is organized into a tree-like structure and the data is stored as records which are connected to one another through links.

A data record is an instance of a data type stored for your application.

For example, Customer records would include data specific to each customer, such as name, email, phone number

Isolation

تنہائی

Deflect  روکنا 

Adam Smith FRSA was a Scottish economist, philosopher, pioneer of political economy, and a key figure during the Scottish Enlightenment. 

Born: June 1723 United Kingdom

Died: July 17, 1790 United Kingdom