---
title: "archi - Cours 1 : subject"
tags: archi, cours
---
{%hackmd theme-dark %}

$$
\newcommand{\vt}[3]{
\begin{pmatrix}
{#1} \\
{#2} \\
{#3}
\end{pmatrix}
}
\newcommand{\limto}[1]{\xrightarrow[#1]{}}
$$

#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