What file is the OS loader boot program?
This version of the Boot Loader Specification is significantly altered from the upstream version. The following changes have been made: Show
TL;DR: Currently there's little cooperation between multiple distributions in dual-boot (or triple, ... multi-boot) setups, and we'd like to improve this situation by getting everybody to commit to a single boot configuration format that is based on drop-in files, and thus is robust, simple, works without rewriting configuration files and is free of namespace clashes. The Boot Loader Specification defines a scheme how different operating systems can cooperatively manage a boot loader configuration directory, that accepts drop-in files for boot menu items that are defined in a format that is shared between various boot loader implementations, operating systems, and userspace programs. The target audience for this specification is:
Of course, without this specification things already work mostly fine. But here's why we think this specification is needed:
The EFI specification provides a boot options logic that can offer similar functionality. Here's why we think that it is not enough for our uses:
Technical DetailsWe define two directories:
These directories are defined below the placeholder file system
Note: In all cases the /org/freedesktop/bls directory should be located directly in the root of the file system. Specifically, if $BOOT is the ESP, then /org/freedesktop/bls directory should be located directly in the root directory of the ESP, and not in the EFI/ subdirectory. Note: 3 was traditionally handled), all installed OS share the same place to drop in their boot-time configuration.For systems where the firmware is able to read filesystems directly, Inside the 8 or the D-Bus machine ID for OSes that lack 8), the kernel version (as returned by 0) and an OS identifier (The ID field of 1). Example: $BOOT/org/freedesktop/bls/entries/6a9857a393724b7a981ebb5b8495b9ea-3.8.0-2.fc19.x86_64.conf`.These configuration snippets shall be Unix-style text files (i.e. line separation with a single newline character), in the UTF-8 character sets. The configuration snippets are loosely inspired on Grub1's configuration syntax. Lines beginning with '#' shall be ignored and used for commenting. The first word of a line is used as key, and shall be separated by a space from its value. The following keys are known:
Each configuration drop-in snippet must include at least a
And here's an example of one using multiboot:
Note that these configurations snippets do not need to be the only configuration source for a boot loader. It may extend this list of entries with additional items from other configuration files (for example its own native configuration files) or automatically detected other entries without explicit configuration. Note that all paths used in the configuration snippets use a Unix-style "/" as path separator. This needs to be converted to an EFI-style "\" separator in EFI boot loaders. PathnamesIt is valid for operating systems to install kernels, initrds, devicetree files or EFI executables under $BOOT/org/freedesktop/bls, although care must be taken to avoid collisions. It is recommended that operating systems use their machine id as a unique parent directory. Example:
If an operating system installs its boot files in an operating system-specific partition, there is no need to embed the machine id in any paths. LogicA boot loader needs a file system driver to discover and read 9 and 5 fields, and possibly others. It uses the file name to identify specific items, for example in case it supports storing away default entry information somewhere. A boot loader should generally not modify these files and must not assume that the filesystem is writable.A kernel installer package installs the kernel and initrd images to either A UI application intended to show available boot options shall operate similar to a boot loader, but might apply additional filters, for example by filtering out the booted OS via the machine ID, or by suppressing all but the newest kernel versions. An OS installer picks the right place for Out of FocusThere are a couple of items that are out of focus for this specifications:
http://www.freedesktop.org/wiki/Software/gummiboot/ http://pkgs.fedoraproject.org/cgit/grub2.git/tree/0460-blscfg-add-blscfg-module-to-parse-Boot-Loader-Specif.patch What is the name of the Windows boot loader file?The Boot. ini file is a text file that contains the boot options for computers with BIOS firmware running NT-based operating system prior to Windows Vista. It's located at the root of the system partition, typically c:\Boot. ini.
What is the OS loader boot program?A boot loader, also called a boot manager, is a small program that places the operating system (OS) of a computer into memory.
Where is Windows bootloader stored?The path element of a Windows boot loader specifies the location of the boot loader on that volume. For UEFI systems, path indicates the Windows boot loader for EFI, whose path is \Windows\System32\Winload.
Where is the boot ini file?Boot. ini is a text file located at the root of the system partition, typically c:\Boot. ini.
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