Operating Systems · Foundations

What an operating system does

The OS as the layer that turns raw, shared hardware into a clean, protected abstraction for programs.

Also known as: OS basics, kernel, role of the operating system.

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Leads to

• System calls and kernel mode: The controlled doorway, a trap into kernel mode, a program uses to ask the OS to do something on its behalf.

Related topics

• The process abstraction: A running program's isolated illusion of its own CPU and memory, tracked by the OS as a process control block.
• System calls and kernel mode: The controlled doorway, a trap into kernel mode, a program uses to ask the OS to do something on its behalf.