作業系統在理論方面相對於許多領域已是相當成熟的，但是要實做一個作業
系統卻相較之下難上許多。舉例來說，Virtual Memory的技術在20年前就已經發展出
來了，要了解這著機制在作業系統中到底如何實做卻不是一件簡單的事。
Minix是最初被用來作為教學用的小型作業系統。但是，麻雀雖小，五臟俱
全，他具備了作業系統開具備的各種要素，並且對應了POSIX的API，是一個完整
的類UNIX作業系統。Minix的第三版已經是一個真正的微內核架構，並且被應用在
嵌入式系統上。微內核的高容錯性與高模組化設計讓應用多變的嵌入式系統的開發
更具彈性。
但是，Minix 3目前只有X86的版本，這篇論文的目的是將Minix移植到
以ARM為基礎的嵌入式系統。以他作為一個實驗性的嵌入式系統平台。並且，因
為Minix 3和IA-32採用的segmented記憶體管理機制和ARM所提供的unsegmented記憶
體管理機制並不相容，所以我們也提供了一組API，簡化了移植的工作。

Theories in operating systems are relatively matured, but implementations are hard
compared to many areas in computer science. For example, virtual memory has been around
for more than 20 years since its introduction, but, to understand how an operating system
supports virtual memory is not a trivial task, let alone implementation.
Minix is an operating system that has been designed for educational purpose. It’s a
good starting point for a novice who wants to learn operating systems. The third version of
Minix has been moved towards a true microkernel design and targeted at small computers and
embedded systems. The advantages of microkernel architecture is its high fault tolerance and
high modularity design which can make it much more flexible for versatile applications on
embedded systems.
However, to the best of our knowledge, Minix 3 only runs on Intel-based machine so
far. The objective of this thesis is thus to port Minix 3 to ARM-Based embedded systems, to
make it an experimental microkernel for embedded systems. Also, due to the incompatibility
between the segmented memory model used by Minix 3 on IA-32 and the unsegmented
memory model support by ARM, we also provide an API to simplify the porting effort.

List of Tables iv
List of Figures v
List of Listings vi
Chapter 1 Introduction 1
1.1 Introduction to Microkernel
1.2 Microkernel and Embedded System
1.3 Introduction to Minix
Chapter 2 Related Hardware and Software
2.1 Target Platform
2.2 Tool-chains
2.2.1 arm-linux-gcc v.s arm-elf-gcc
2.3 The SkyEye Simulator
2.4 Bootstrap Loader
2.5 Difference in Address Space between Monolithic Kernel and Microkernel
Chapter 3 Porting the Minix 3 Kernel
3.1 Overview
3.2 Introduction to Minix 3 Kernel
3.3 Implementation on SkyEye
3.3.1 Bootstrapping
3.3.2 Starting up the First Process
3.3.3 Sending Messages to the Virtual Console
3.3.4 Putting All Together
3.3.5 Implementation of Software Interrupt
3.4 Moving from SkyEye to Hardware Platform
3.4.1 Loading the Kernel Image to the Target Platform
3.4.2 Porting U-Boot to the Target Platform
3.4.3 Changes Made for the Target Platform
3.4.4 Simplifying the Context Switch Code
3.5 Implementation of Interrupt Dispatcher
3.5.1 Introduction to S3C2410 Interrupt Controller
3.5.2 Overview of Minix 3 Interrupt Dispatcher
3.5.3 Details of Implementation
3.5.4 Testing
Chapter 4 Porting Upper Layer Software
4.1 Overview
4.2 Memory Management Unit (MMU)
4.2.1 Memory Object Abstraction
4.2.2 Implementation
4.3 Upper Layer Software
4.3.1 Memory Driver
4.3.2 File System Server
4.3.3 Terminal driver
4.3.4 Process Manager Server
4.3.5 setjmp() and longjmp()
Chapter 5 Related Work
5.1 L4 Microkernel Family
5.2 Features Being Added on Minix 3
5.3 Minix-vmd
Chapter 6 Conclusion and Future Works
6.1 Conclusion
6.2 Future works

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