The Linux Startup Process
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Booting up and Shutting Down a Primer for Troubleshooting the Boot
Booting up and Shutting down A primer for troubleshooting In this section, we touch upon the startup and shutdown process on Linux. It is beyond the scope of this course to cover this topic in depth and we highly recommend that you read more about this topic in the official RedHat documentation or the documents listed at the end of this section. There is an abundance of information on this topic available in books and on the web. The Boot Up Process Please refer to the official RedHat documentation for details about the boot up process. http://www.redhat.com/docs/manuals/linux/RHL-9-Manual/ref-guide/ch-boot-init-shutdown.html Bootloaders Two common bootloaders in Linux are Lilo and grub. Bio-Linux currently uses grub. Grub installs a boot loader to the Master Boot Record. By configuring grub, you can put specific instructions in the Master Boot Record that allow you to load menus or command environments such that you could choose to start up different operating systems, pass information to the kernel, etc. The grub configuration file is at /boot/grub/grub.conf. Unless you are really into system work, you will probably not ever have to touch this file. More information on grub can be found at: http://www.redhat.com/docs/manuals/linux/RHL-9-Manual/ref-guide/s1-grub-whatis.html Once grub has done its job, it hands over control of the machine to the operating system. Run levels Run Level Description 0 Halt 1 Single user mode 2 Multiuser, without networking (without NFS) 3 Full multiuser mode, with networking 4 Unused 5 the same as 3, but with X11 started automatically 6 Reboot The first process run after the kernel has loaded is /sbin/init – this runs with pid 1. -
It's Complicated but It's Probably Already Booting Your Computer
FAQ SYSTEMD SYSTEMD It’s complicated but it’s probably already booting your computer. dynamically connect to your network, a runlevel of 1 for a single-user mode, GRAHAM MORRISON while syslogd pools all the system runlevel 3 for the same command messages together to create a log of prompt we described earlier, and Surely the ‘d’ in Systemd is everything important. Another daemon, runlevel 5 to launch a graphical a typo? though it lacks the ‘d’, is init – famous environment. Changing this for your No –it’s a form of Unix notation for being the first process that runs on next boot often involved editing the used to signify a daemon. your system. /etc/inittab file, and you’d soon get used to manually starting and stopping You mean like those little Isn’t init used to switch your own services simply by executing devils inhabiting Dante’s between the command-line the scripts you found. underworld? and the graphical desktop? There is a link in that Unix usage For many of us, yes. This was the You seem to be using the past of the term daemon supposedly main way of going from the tense for all this talk about the comes from Greek mythology, where desktop to a command line and back init daemon… daemons invisibly wove their magic again without trying to figure out which That’s because the and benign influence. The word is today processes to kill or start manually. aforementioned Systemd wants more commonly spelt ‘demon’, which Typing init 3 would typically close any to put init in the past. -
Linux Boot Loaders Compared
Linux Boot Loaders Compared L.C. Benschop May 29, 2003 Copyright c 2002, 2003, L.C. Benschop, Eindhoven, The Netherlands. Per- mission is granted to make verbatim copies of this document. This is version 1.1 which has some minor corrections. Contents 1 introduction 2 2 How Boot Loaders Work 3 2.1 What BIOS does for us . 3 2.2 Parts of a boot loader . 6 2.2.1 boot sector program . 6 2.2.2 second stage of boot loader . 7 2.2.3 Boot loader installer . 8 2.3 Loading the operating system . 8 2.3.1 Loading the Linux kernel . 8 2.3.2 Chain loading . 10 2.4 Configuring the boot loader . 10 3 Example Installations 11 3.1 Example root file system and kernel . 11 3.2 Linux Boot Sector . 11 3.3 LILO . 14 3.4 GNU GRUB . 15 3.5 SYSLINUX . 18 3.6 LOADLIN . 19 3.7 Where Can Boot Loaders Live . 21 1 4 RAM Disks 22 4.1 Living without a RAM disk . 22 4.2 RAM disk devices . 23 4.3 Loading a RAM disk at boot time . 24 4.4 The initial RAM disk . 24 5 Making Diskette Images without Diskettes 25 6 Hard Disk Installation 26 7 CD-ROM Installation 29 8 Conclusions 31 1 introduction If you use Linux on a production system, you will only see it a few times a year. If you are a hobbyist who compiles many kernels or who uses many operating systems, you may see it several times per day. -
The Linux 2.4 Kernel's Startup Procedure
The Linux 2.4 Kernel’s Startup Procedure William Gatliff 1. Overview This paper describes the Linux 2.4 kernel’s startup process, from the moment the kernel gets control of the host hardware until the kernel is ready to run user processes. Along the way, it covers the programming environment Linux expects at boot time, how peripherals are initialized, and how Linux knows what to do next. 2. The Big Picture Figure 1 is a function call diagram that describes the kernel’s startup procedure. As it shows, kernel initialization proceeds through a number of distinct phases, starting with basic hardware initialization and ending with the kernel’s launching of /bin/init and other user programs. The dashed line in the figure shows that init() is invoked as a kernel thread, not as a function call. Figure 1. The kernel’s startup procedure. Figure 2 is a flowchart that provides an even more generalized picture of the boot process, starting with the bootloader extracting and running the kernel image, and ending with running user programs. Figure 2. The kernel’s startup procedure, in less detail. The following sections describe each of these function calls, including examples taken from the Hitachi SH7750/Sega Dreamcast version of the kernel. 3. In The Beginning... The Linux boot process begins with the kernel’s _stext function, located in arch/<host>/kernel/head.S. This function is called _start in some versions. Interrupts are disabled at this point, and only minimal memory accesses may be possible depending on the capabilities of the host hardware. -
Question Bank Mca Semester V Vol. I
QUESTION BANK MCA SEMESTER V VOL. I 1 FOR PRIVATE CIRCULATION The Questions contained in this booklet have been prepared by the faculty of the Institute from the sources believed to be reliable. Neither the Institute nor the faculty gives any guarantee with respect to completeness or accuracy of the contents contained in the booklet and shall in no event be liable for any errors, omissions or damages arising out of use of the matter contained in the booklet. The Institute and the faculty specifically disclaim any implied warranty as to merchantability or fitness of the information for any particular purpose. 2 QUESTION BANK LINUX PROGRAMMING MCA 301 3 QUESTION BANK LINUX PROGRAMMING - MCA 301 MCA V UNIT - I I Test Your Skills: (a) State Whether the Following Statements are True or False: 1 The “no” option informs the machine that there is no grace period or time to wait for other users to log off. 2 Telnet command is used for changing the run level or state of the computer without rebooting. 3 IP address is a unique identifier for the system. 4 Transmission control protocol (TCP) builds on top of UPS and certifies that each message has been received. 5 Cron is known for arranging the files in the disk in chronological manner. 6 ARP (Address Resolution Protocol) converts IP address to MAC Address. 7 UNIX is a command-based system. 8 A program is synonymous with a process. 9 All UNIX flavors today offer a Command User Interface. 10 The operating system allocates memory for the program and loads the program to the allocated memory. -
Implementing Full Device Cloning on the NVIDIA Jetson Platform
Implementing Full Device Cloning on the NVIDIA Jetson Platform March 2, 2018 Calvin Chen Linh Hoang Connor Smith Advisor: Professor Mark Claypool Sponsor - Mentor : NVIDIA - Jimmy Zhang Abstract NVIDIA’s Linux For Tegra development team provides support for many tools which exist on the Jetson-TX2 embedded AI computing device. While tools to clone the user partitions of the Jetson-TX2 exist, no tool exists to fully backup and restore all of the partitions and configurations of these boards. The goal of this project was to develop a tool that allows a user to create a complete clone of the Jetson-TX2 board’s partitions and their contents. We developed a series of bash scripts that fully backup the partitions and configurations of one Jetson-TX2 board and restore them onto another board of the same type. 1 Table of Contents Abstract 1 Table of Contents 2 1 Introduction 3 2 Background 5 2.1 Preliminary Research 5 2.1.1 UEFI Booting and Flashing 5 2.1.2 Tegra Linux Driver Package 8 2.1.3 Network File System 8 2.1.4 Jetson TX2 Bootloader 10 2.2 Linux Terminology, RCM boot and Initial ramdisk 12 2.2.1 Linux Terminology 12 2.2.2 USB Recovery Mode (RCM) Boot 13 2.2.3 Initial Ramdisk 14 2.3 Associated Technologies 15 2.3.1 Linux tools 15 2.3.2 Serial Console 16 3 Methodology 17 4 Product 20 4.1 Backup Script 20 4.2 Restore Script 22 4.3 Initial ramdisk (initrd) 24 4.4 Script Development Guidelines 26 4.4.1 Use Case 26 4.4.2 Integrity 26 4.4.3 Performance 27 5 Future Work 29 6 Conclusions 30 7 Bibliography 31 2 1 Introduction The Jetson-TX2 is a low power, high performance embedded artificial intelligence supercomputer utilized in many modern technologies. -
Effective Cache Apportioning for Performance Isolation Under
Effective Cache Apportioning for Performance Isolation Under Compiler Guidance Bodhisatwa Chatterjee Sharjeel Khan Georgia Institute of Technology Georgia Institute of Technology Atlanta, USA Atlanta, USA [email protected] [email protected] Santosh Pande Georgia Institute of Technology Atlanta, USA [email protected] Abstract cache partitioning to divide the LLC among the co-executing With a growing number of cores per socket in modern data- applications in the system. Ideally, a cache partitioning centers where multi-tenancy of a diverse set of applications scheme obtains overall gains in system performance by pro- must be efficiently supported, effective sharing of the last viding a dedicated region of cache memory to high-priority level cache is a very important problem. This is challenging cache-intensive applications and ensures security against because modern workloads exhibit dynamic phase behaviour cache-sharing attacks by the notion of isolated execution in - their cache requirements & sensitivity vary across different an otherwise shared LLC. Apart from achieving superior execution points. To tackle this problem, we propose Com- application performance and improving system throughput CAS, a compiler guided cache apportioning system that pro- [7, 20, 31], cache partitioning can also serve a variety of pur- vides smart cache allocation to co-executing applications in a poses - improving system power and energy consumption system. The front-end of Com-CAS is primarily a compiler- [6, 23], ensuring fairness in resource allocation [26, 36] and framework equipped with learning mechanisms to predict even enabling worst case execution-time analysis of real-time cache requirements, while the backend consists of allocation systems [18]. -
A Reliable Booting System for Zynq Ultrascale+ Mpsoc Devices
A reliable booting system for Zynq Ultrascale+ MPSoC devices An embedded solution that provides fallbacks in different parts of the Zynq MPSoC booting process, to assure successful booting into a Linux operating system. A thesis presented for the Bachelor of Science in Electrical Engineering at the University of Applied Sciences Utrecht Name Nekija Dˇzemaili Student ID 1702168 University supervisor Corn´eDuiser CERN supervisors Marc Dobson & Petr Zejdlˇ Field of study Electrical Engineering (embedded systems) CERN-THESIS-2021-031 17/03/2021 February 15th, 2021 Geneva, Switzerland A reliable booting system for Zynq Ultrascale+ MPSoC devices Disclaimer The board of the foundation HU University of Applied Sciences in Utrecht does not accept any form of liability for damage resulting from usage of data, resources, methods, or procedures as described in this report. Duplication without consent of the author or the college is not permitted. If the graduation assignment is executed within a company, explicit consent of the company is necessary for duplication or copying of text from this report. Het bestuur van de Stichting Hogeschool Utrecht te Utrecht aanvaardt geen enkele aansprakelijkheid voor schade voortvloeiende uit het gebruik van enig gegeven, hulpmiddel, werkwijze of procedure in dit verslag beschreven. Vermenigvuldiging zonder toestemming van de auteur(s) en de school is niet toegestaan. Indien het afstudeerwerk in een bedrijf is verricht, is voor vermenigvuldiging of overname van tekst uit dit verslag eveneens toestemming van het bedrijf vereist. N. Dˇzemaili page 1 of 110 A reliable booting system for Zynq Ultrascale+ MPSoC devices Preface This thesis was written for the BSc Electrical Engineering degree of the HU University of Applied Sciences Utrecht, the Netherlands. -
Linux Booting Procedure How Linux Boot?
Linux Booting Procedure How Linux boot? 2 What is “boot”? • boot (n.) [1] http://en.wikipedia.org/wiki/Boot 4 Brief etymology[2] • Phrase “pull oneself up by one’s bootstraps” • Misattributed (at latest in 1901!) to “The Surprising Adventures of Baron Munchausen” (1781, Rudolf Erich Raspe) : The baron pulls himself out of a swamp by his hair (pigtail). • The use of this phrase is found in 1834 in the U.S. • “[S]omeone is attempting or has claimed some ludicrously far-fetched or impossible task” • In the 20th century, the “possible bootstrap[3] task” meaning has appeared • “To begin an enterprise or recover from a setback without any outside help; to succeed only on one's own effort or abilities” 5 [2] http://en.wiktionary.org/wiki/pull_oneself_up_by_one%27s_bootstraps [3] http://en.wikipedia.org/wiki/Bootstrapping Bootstrapping (in Computer) • The process of loading the basic software (typically, operating systems) into the main memory from persistent memory (HDD, flash ROM, etc.) • “Boot” is an abbreviation for “bootstrap(ping)” Boostrapping Code 6 System startup Booting sequence 1. Tern on 2. CPU jump to address of BIOS (0xFFFF0) 3. BIOS runs POST (Power-On Self Test) 4. Find bootale devices 5. Loads and execute boot sector form MBR 6. Load OS 5 BIOS (Basic Input/Output System) BIOS refers to the software code run by a computer when first powered on The primary function of BIOS is code program embedded on a chip that recognises and controls various devices that make up the computer. BIOS on board BIOS on screen 6 How computer startup? Booting is a bootstrapping process that starts operating systems when the user turns on a computer system A boot sequence is the set of operations the computer performs when it is switched on that load an operating system 4 Boot loader MBR (Master Boot Record) OS is booted from a hard disk, where the Master Boot Record (MBR) contains the primary boot loader The MBR is a 512-byte sector, located in the first sector on the disk (sector 1 of cylinder 0, head 0) After the MBR is loaded into RAM, the BIOS yields control to it. -
MX-19.2 Users Manual
MX-19.2 Users Manual v. 20200801 manual AT mxlinux DOT org Ctrl-F = Search this Manual Ctrl+Home = Return to top Table of Contents 1 Introduction...................................................................................................................................4 1.1 About MX Linux................................................................................................................4 1.2 About this Manual..............................................................................................................4 1.3 System requirements..........................................................................................................5 1.4 Support and EOL................................................................................................................6 1.5 Bugs, issues and requests...................................................................................................6 1.6 Migration............................................................................................................................7 1.7 Our positions......................................................................................................................8 1.8 Notes for Translators.............................................................................................................8 2 Installation...................................................................................................................................10 2.1 Introduction......................................................................................................................10 -
Debian GNU/Linux Installation Guide
Debian GNU/Linux Installation Guide July 31, 2021 Debian GNU/Linux Installation Guide Copyright © 2004 – 2021 the Debian Installer team This manual is free software; you may redistribute it and/or modify it under the terms of the GNU General Public License. Please refer to the license in Appendix F. Build version of this manual: 20210730. i Contents 1 Welcome to Debian 1 1.1 What is Debian? . 1 1.2 What is GNU/Linux? . 1 1.3 What is Debian GNU/Linux? . 2 1.4 What is the Debian Installer? . 3 1.5 Getting Debian . 3 1.6 Getting the Newest Version of This Document . 3 1.7 Organization of This Document . 3 1.8 About Copyrights and Software Licenses . 4 2 System Requirements 5 2.1 Supported Hardware . 5 2.1.1 Supported Architectures . 5 2.1.2 CPU, Main Boards, and Video Support . 6 2.1.2.1 CPU . 6 2.1.2.2 I/O Bus . 6 2.1.3 Laptops . 6 2.1.4 Multiple Processors . 6 2.1.5 Graphics Hardware Support . 6 2.1.6 Network Connectivity Hardware . 7 2.1.6.1 Wireless Network Cards . 7 2.1.7 Braille Displays . 7 2.1.8 Hardware Speech Synthesis . 7 2.1.9 Peripherals and Other Hardware . 7 2.2 Devices Requiring Firmware . 7 2.3 Purchasing Hardware Specifically for GNU/Linux . 8 2.3.1 Avoid Proprietary or Closed Hardware . 8 2.4 Installation Media . 8 2.4.1 CD-ROM/DVD-ROM/BD-ROM . 9 2.4.2 USB Memory Stick . -
Installing Fedora the Installation • Choosing How to Install Fedora
CHAPTER 3 IN THIS CHAPTER • Before You Begin Installing Fedora the Installation • Choosing How to Install Fedora This chapter shows you how to get a basic installation of • Step-by-Step Installation Fedora up and running. You will learn how to start installa- tion, as well as specify certain configuration options during • Logging In and Shutting the install. Before you even insert the disc, we will take a Down look at some considerations you need to think about that • Reference will affect how you install Fedora. It is impossible to take you through every single variation of the install, but you will get a step-by-step guide of a typical installation, includ- ing how to log in to your new system and shut down or reboot the system. Before You Begin the Installation Installing a new operating system is a major event and you should make sure that you have properly thought through what is going to take place. The first thing you should consider is how the hardware will be affected by the soft- ware that you propose to install. Although Fedora runs well on an extremely wide variety of hardware, it is worthwhile checking out your hardware components because there may be a banana peel waiting for you to slip up on. The following sections provide some areas for you to investigate and think about, and may even save you hours of frustra- tion when something goes wrong. The sections are designed to complement the ideas and checklists presented in Chapter 2, “Preparing to Install Fedora.” You start by researching and documenting your hardware.