Boot folder

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In Unix-like operating systems, a boot folder is the directory which holds files used in booting the operating system, typically /boot. The usage is standardized within Linux in the Filesystem Hierarchy Standard. [1]

Contents

Contents

The contents are mostly Linux kernel files or boot loader files, depending on the boot loader, most commonly (on Linux) LILO or GRUB.

Linux

LILO

LILO creates and uses the following files:

LILO may also use other files, such as message and also stores a non-boot configuration file in /etc/lilo.conf.

GRUB

GRUB stores its files in the subdirectory grub/ (i.e. /boot/grub/). These files are mostly modules (.mod), with configuration stored in grub.cfg.

Location

/boot/ is often simply a directory on the main (or only) hard drive partition. However, it may be a separate partition. A separate partition is generally only used when bootloaders are incapable of reading the main filesystem (e.g. LILO does not recognize XFS) or other problems not easily resolvable by users.[ citation needed ]

On UEFI systems, including most modern PCs, the EFI system partition is often mounted at /boot/, /efi/ or /boot/efi/. [6] [7]

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<span class="mw-page-title-main">Disk partitioning</span> Creation of separate accessible storage areas on a secondary computer storage device

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<span class="mw-page-title-main">Boot sector</span> Sector of a persistent data storage device

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<span class="mw-page-title-main">GNU GRUB</span> Boot loader package

GNU GRUB is a boot loader package from the GNU Project. GRUB is the reference implementation of the Free Software Foundation's Multiboot Specification, which provides a user the choice to boot one of multiple operating systems installed on a computer or select a specific kernel configuration available on a particular operating system's partitions.

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Multi-booting is the act of installing multiple operating systems on a single computer, and being able to choose which one to boot. The term dual-booting refers to the common configuration of specifically two operating systems. Multi-booting may require a custom boot loader.

<span class="mw-page-title-main">Bootloader</span> Software responsible for starting the computer and load other software to the CPU memory

A bootloader, also spelled as boot loader or called bootstrap loader, is a computer program that is responsible for booting a computer. If it also provides an interactive menu with multiple boot choices then it's often called a boot manager.

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Unified Extensible Firmware Interface is a specification for the firmware architecture of a computing platform. When a computer is powered on, the UEFI-implementation is typically the first that runs, before starting the operating system. Examples include AMI Aptio, Phoenix SecureCore, TianoCore EDK II, InsydeH2O.

vmlinux Executable file containing the Linux kernel

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<span class="mw-page-title-main">GUID Partition Table</span> Computer disk partitioning standard

The GUID Partition Table (GPT) is a standard for the layout of partition tables of a physical computer storage device, such as a hard disk drive or solid-state drive, using universally unique identifiers (UUIDs), which are also known as globally unique identifiers (GUIDs). Forming a part of the Unified Extensible Firmware Interface (UEFI) standard, it is nevertheless also used for some BIOSs, because of the limitations of master boot record (MBR) partition tables, which use 32 bits for logical block addressing (LBA) of traditional 512-byte disk sectors.

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The SPARC Improved bootLOader (SILO) is the bootloader used by the SPARC port of the Linux operating system; it can also be used for Solaris as a replacement for the standard Solaris boot loader.

<span class="mw-page-title-main">EFI system partition</span> Partition used by Unified Extensible Firmware Interface

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<span class="mw-page-title-main">Windows Boot Manager</span> Boot process used in modern Windows NT-based products

The Windows Boot Manager (BOOTMGR) is the bootloader provided by Microsoft for Windows NT versions starting with Windows Vista and Windows Server 2008. It is the first program launched by the BIOS or UEFI of the computer and is responsible for loading the rest of Windows. It replaced the NTLDR present in older versions of Windows.

The following tables compare general and technical information for a number of available bootloaders.

The Linux booting process involves multiple stages and is in many ways similar to the BSD and other Unix-style boot processes, from which it derives. Although the Linux booting process depends very much on the computer architecture, those architectures share similar stages and software components, including system startup, bootloader execution, loading and startup of a Linux kernel image, and execution of various startup scripts and daemons. Those are grouped into 4 steps: system startup, bootloader stage, kernel stage, and init process.

The BIOS boot partition is a partition on a data storage device that GNU GRUB uses on legacy BIOS-based personal computers in order to boot an operating system, when the actual boot device contains a GUID Partition Table (GPT). Such a layout is sometimes referred to as BIOS/GPT boot.

<span class="mw-page-title-main">EasyBCD</span> Software for Microsoft Windows

EasyBCD is a program developed by NeoSmart Technologies to configure and tweak the Boot Configuration Data (BCD), a boot database first introduced in Windows Vista and used in all subsequent Windows releases. EasyBCD can be used to set up multi-boot environments for computers on which some versions of Windows, Linux, BSD and Mac OS X can be simultaneously installed; EasyBCD can also be used for adding entries to bootable tools and utilities, as well as modifying and controlling the behavior of the Windows boot menu. EasyBCD 2.3 introduced additional support for creating and managing entries for UEFI-based Windows entries in the boot menu. As of June 20, 2011 with the release of EasyBCD 2.1, it is no longer free for use in commercial environments which require the purchase of a paid license, however it remains free for home and non-profit use without limitations.

A master boot record (MBR) is a type of boot sector in the first block of partitioned computer mass storage devices like fixed disks or removable drives intended for use with IBM PC-compatible systems and beyond. The concept of MBRs was publicly introduced in 1983 with PC DOS 2.0.

rEFInd Boot manager for UEFI systems

rEFInd is a boot manager for UEFI and EFI-based machines. It can be used to boot multiple operating systems that are installed on a single non-volatile device. It also provides a way to launch UEFI applications.

References

  1. "3.5. /boot : Static files of the boot loader". Linux Foundation Referenced Specifications. March 19, 2015. Retrieved June 7, 2021.
  2. Ward, Brian (2004). How Linux works what every superuser should know. San Francisco: No Starch Press. p. 219. ISBN   1593270356.
  3. Lombardo, John (2001). Embedded Linux. Indianapolis, Ind: New Riders. p. 17. ISBN   9780735709980.
  4. Kopper, Karl (2008). The Linux Enterprise Cluster build a highly available cluster with commodity hardware and free software. San Francisco: No Starch Press. p. 61. ISBN   978-1593270360.
  5. "LILO mini-HOWTO: Background Information and Standard Installation". tldp.org. Retrieved 2022-11-26.
  6. "EFI System Partition - Gentoo wiki". wiki.gentoo.org. Retrieved 2024-02-15.
  7. "EFI system partition - ArchWiki". wiki.archlinux.org. Retrieved 2024-02-15.