INITIALIZATION Knowledgebase: ki-dev-large Base Query: based on The little book about OS development Model: gemini-1.5-pro-preview-0409 Use Curl?: None ================================================== **Elapsed Time: 0.00 seconds** ================================================== ROUTING Query type: research ================================================== **Elapsed Time: 1.97 seconds** ================================================== RAG PARAMETERS Max Context To Include: 20 Lowest Score to Consider: 0.5 ================================================== **Elapsed Time: 0.14 seconds** ================================================== VECTOR SEARCH ALGORITHM TO USE Use MMR search?: False Use Similarity search?: True ================================================== **Elapsed Time: 0.10 seconds** ================================================== VECTOR SEARCH DONE ================================================== **Elapsed Time: 0.77 seconds** ================================================== FILENAMES AND KEYWORDS Keywords Found: ['development', 'OS'] All file names: ['The%20Little%20Book%20About%20OS%20Development%20-%20Erik%20Helin%2C%20Adam%20Renberg%20-%20%28PDF%2C%20HTML%29.pdf', 'The%20Little%20Book%20About%20OS%20Development%20-%20Erik%20Helin%2C%20Adam%20Renberg%20-%20%28PDF%2C%20HTML%29.pdf', 'The%20Little%20Book%20About%20OS%20Development%20-%20Erik%20Helin%2C%20Adam%20Renberg%20-%20%28PDF%2C%20HTML%29.pdf', 'The%20Little%20Book%20About%20OS%20Development%20-%20Erik%20Helin%2C%20Adam%20Renberg%20-%20%28PDF%2C%20HTML%29.pdf'] File names to FILTER: ['The%20Little%20Book%20About%20OS%20Development%20-%20Erik%20Helin%2C%20Adam%20Renberg%20-%20%28PDF%2C%20HTML%29.pdf'] ================================================== **Elapsed Time: 1.09 seconds** ================================================== PRIMER Primer: You are Simon, a highly intelligent personal assistant in a system called KIOS. You are a chatbot that can read knowledgebases through the "CONTEXT" that is included in the user's chat message. Your role is to act as an expert at reading the information provided by the user and giving the most relevant information. In your responses to enterprise users, prioritize clarity, trustworthiness, and appropriate formality. Be honest by admitting when a topic falls outside your scope of knowledge, and suggest alternative avenues for obtaining information when necessary. Make effective use of chat history to avoid redundancy and enhance response relevance, continuously adapting to integrate all necessary details in your interactions. Focus on precision and accuracy of your answers information. ================================================== **Elapsed Time: 0.00 seconds** ================================================== FINAL QUERY Final Query: CONTEXT: ########## File: The%20Little%20Book%20About%20OS%20Development%20-%20Erik%20Helin%2C%20Adam%20Renberg%20-%20%28PDF%2C%20HTML%29.pdf Page: 1 Context: ```markdown # The little book about OS development **Authors:** Erik Helin, Adam Renberg **Date:** 2015-01-19 **Commit:** fe8e3e27dab3c399303354d2lea38f6d4ee2928212 ``` #################### File: The%20Little%20Book%20About%20OS%20Development%20-%20Erik%20Helin%2C%20Adam%20Renberg%20-%20%28PDF%2C%20HTML%29.pdf Page: 7 Context: ```markdown # Chapter 1 ## Introduction This text is a practical guide to writing your own x86 operating system. It is designed to give enough help with the technical details while at the same time not reveal too much with samples and code excerpts. We’ve tried to collect parts of the vast (and often excellent) expanse of material and tutorials available, on the web and otherwise, and add our own insights into the problems we encountered and struggled with. This book is not about the theory behind operating systems, or how any specific operating system (OS) works. For OS theory, we recommend the book *Modern Operating Systems* by Andrew Tanenbaum [1]. Lists and details on current operating systems are available on the Internet. The starting chapters are quite detailed and explicit, to quickly get you into coding. Later chapters give more of an outline of what is needed, as more and more of the implementation and design comes up to the reader, who should now be more familiar with the world of kernel development. At the end of some chapters there are links for further reading, which might be interesting and give a deeper understanding of the topics covered. In chapters 2 and 3 we set up our development environment and boot up our OS kernel in a virtual machine, eventually starting to write code in C. We continue in chapter 4 with writing to the screen and the serial port, and then we dive into segmentation in chapter 5 and interrupts and input in chapter 6. After this we have a quite functional but bare-bones OS kernel. In chapter 7 we start the road to user mode applications, with virtual memory through paging (chapters 8 and 9), memory allocation (chapter 10), and finally running a user application in chapter 11. In the last three chapters we discuss the more advanced topics of file systems (chapter 12), system calls (chapter 13), and multitasking (chapter 14). ## About the Book The OS kernel and this book were produced as part of an advanced individual course at the Royal Institute of Technology [2], Stockholm. The authors had previously taken courses in OS theory, but had only limited practical experience with OS kernel development. In order to get more insight and a deeper understanding of how the theory from the previous OS courses works in practice, the authors decided to create a new course, which focused on the development of a small OS. Another goal of the course was writing a thorough tutorial on how to develop a small OS basically from scratch, and this short book is the result. The x86 architecture is, and has been for a long time, one of the most common hardware architectures. It was not a difficult choice to use the x86 architecture as the target of the OS, with its large community, extensive ``` #################### File: The%20Little%20Book%20About%20OS%20Development%20-%20Erik%20Helin%2C%20Adam%20Renberg%20-%20%28PDF%2C%20HTML%29.pdf Page: 8 Context: ```markdown # Reference Material The OS was developed in about six weeks of full-time work. The implementation was done in many small steps, and after each step the OS was tested manually. By developing in this incremental and iterative way, it was often easier to find any bugs that were introduced, since only a small part of the code had changed since the last known good state of the code. We encourage the reader to work in a similar way. During the six weeks of development, almost every single line of code was written by the authors together (this way of working is also called pair-programming). It is our belief that we managed to avoid a lot of bugs due to this style of development, but this is hard to prove scientifically. ## The Reader The reader of this book should be comfortable with UNIX/Linux, systems programming, the C language, and computer systems in general (such as hexadecimal notation [3]). This book could be a way to get started learning those things, but it will be more difficult, and developing an operating system is already challenging on its own. Search engines and other tutorials are often helpful if you get stuck. ## Credits, Thanks and Acknowledgements We'd like to thank the OSDev community [4] for their great wiki and helpful members, and James Malloy for his eminent kernel development tutorial [5]. We'd also like to thank our supervisor Torbjørn Granlund for his insightful questions and interesting discussions. Most of the CSS formatting of the book is based on the work by Scott Chacon for the book Pro Git, [http://progit.org](http://progit.org). ## Contributors We are very grateful for the patches that people send us. The following users have all contributed to this book: - alexschneider - Arvidanborisov - nirs - kedarambaswade - vamanaea - ansjob ## Changes and Corrections This book is hosted on GitHub - if you have any suggestions, comments or corrections, just fork the book, write your changes, and send us a pull request. We'll happily incorporate anything that makes this book better. ``` #################### File: The%20Little%20Book%20About%20OS%20Development%20-%20Erik%20Helin%2C%20Adam%20Renberg%20-%20%28PDF%2C%20HTML%29.pdf Page: 12 Context: ```markdown # Host Operating System All the code examples assume that the code is being compiled on a UNIX-like operating system. All code examples have been successfully compiled using Ubuntu [6] versions 11.04 and 11.10. # Build System Make [13] has been used when constructing the Makefile examples. # Virtual Machine When developing an OS, it is very convenient to be able to run your code in a virtual machine instead of on a physical computer, since starting your OS in a virtual machine is much faster than getting your OS onto a physical medium and then running it on a physical machine. Bochs [14] is an emulator for the x86 (IA-32) platform which is well suited for OS development due to its debugging features. Other popular choices are QEMU [15] and VirtualBox [7]. This book uses Bochs. By using a virtual machine, we cannot ensure that our OS works on real physical hardware. The environment simulated by the virtual machine is designed to be very similar to their physical counterparts, and the OS can be tested on one by just copying the executable to a CD and finding a suitable machine. # Booting Booting an operating system consists of transferring control along a chain of small programs, each one more "powerful" than the previous one, where the operating system is the last "program". See the following figure for an example of the boot process: ``` BIOS → GRUB1 → GRUB2 → OS ``` **Figure 2.1**: An example of the boot process. Each box is a program. # BIOS When the PC is turned on, the computer will start a small program that adheres to the Basic Input Output System (BIOS) [16] standard. This program is usually stored on a read-only memory chip on the motherboard of the PC. The original role of the BIOS program was to export some library functions for printing to the screen, reading keyboard input, etc. Modern operating systems do not use the BIOS' functions; they use... ``` ########## """QUERY: based on The little book about OS development""" Consider the chat history for relevant information.Important: Take a look at the QUERY and only the QUERY. If this is vague or unclear, please ignore everything and ask a follow-up question instead! Final Files Sources: The%20Little%20Book%20About%20OS%20Development%20-%20Erik%20Helin%2C%20Adam%20Renberg%20-%20%28PDF%2C%20HTML%29.pdf - Page 1, The%20Little%20Book%20About%20OS%20Development%20-%20Erik%20Helin%2C%20Adam%20Renberg%20-%20%28PDF%2C%20HTML%29.pdf - Page 7, The%20Little%20Book%20About%20OS%20Development%20-%20Erik%20Helin%2C%20Adam%20Renberg%20-%20%28PDF%2C%20HTML%29.pdf - Page 8, The%20Little%20Book%20About%20OS%20Development%20-%20Erik%20Helin%2C%20Adam%20Renberg%20-%20%28PDF%2C%20HTML%29.pdf - Page 12 ================================================== **Elapsed Time: 0.00 seconds** ================================================== FINAL ANSWER Answer: Please clarify your query. What information are you looking for from "The Little Book About OS Development"? ================================================== **Elapsed Time: 1.90 seconds** ==================================================