Operating System Components

Three Easily Defined Operating System Components

Kernel

This provides basic-level control over all of the computer hardware devices.
Main roles include reading data from memory and writing data to memory, processing execution orders, determining how data is received and sent by devices, such as the monitor, keyboard and mouse; and determining how to interpret data received from networks.
Monolithic kernels have a simpler design and consist of a single code that communicates with all hardware and software.
Microkernels implement user and kernel services in different address spaces, reducing their size, but forcing the use of message passing to execute services.

User Interface (UI)

This component allows interaction with the user, which may occur through graphical icons and a desktop or through a command line.
The UI is further divided into Command Line Interface (CLI), consisting of a text-based interface where advanced users can prompt specific commands by typing them, and a Graphical User Interface (GUI).
The latter is a visual interface that allows the end user to issue commands by interacting with symbols, icons, and menus using an input device such as a mouse or touchpad.

Application Programming Interfaces (API)

This component allows application developers to write modular code.
An API defines how other systems or components can use a certain application.

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