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title: 'archi - Cours 1 : subject'
tags: [' cours', archi]

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title: "archi - Cours 1 : subject"
tags: archi, cours
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#Architecture - Cours 0 : Subject

[`video`](url_video)
[`cours`](url_cours)
[`slides`](url_slides)

## Introduction

livre:
- basic architecture concepts required
- what is an os


## basic architecture concepts required

- CPU: central processing unit
  - register: variable of the CPU
- frbice: hardware
- interruption: way to handle an event for the CPU
  - hardware interrupt or IRQ: Interruption from hardware
  - Software interrupt: interuption from sofware

BUS: c'est un vecteur de donné. enpratique ensemble de file qui ensemble transmet 1 donnée

## Basic architecture concepts required

- Protection rigns:
  - model of protection
  - Levels/Layers of autorisations
  - Each level has specific permissions
  
Exemple
- Intel example: 4 level
  - ring 0 = most privileged mode - Supervisor mode - privileged mode:
    - context in witch the CPU allows more actions
    - allows access to restricted memory addresses (you might not want that another program erase )
  - ...
  - ring 3 = least privieged mode (regular mode)

# What is an OS

Operating systems perform two essentially unrelated functions: provioded application programmers (and application programs, naturally)a clean abstract set of resources intead of the messy hardware ones and managing these hardware resource.

An operationg system is software that manages a computers's hardware. It also provodes a basis for application programs and acts as an intermediary between the computer use 

