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Linux is a family of open source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991 by Linus Torvalds. Linux is typically packaged in a Linux distribution (or distro for short).

Distributions include the Linux kernel and supporting system software and libraries, many of which are provided by the GNU Project. Many Linux distributions use the word "Linux" in their name, but the Free Software Foundation uses the name GNU/Linux to emphasize the importance of GNU software, causing some controversy.

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What are all the files/folders that will be in the filesystem after initrd? (lemmy.zip)

submitted 1 week ago by SpiderUnderUrBed@lemmy.zip to c/linux@lemmy.ml

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is /run shared to the real filesystem after the initrd stage? like what directories are shared to the real filesystem after initrd, or what files. Or is everything just inaccessible in the real filesystem from the initrd phase.

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[–] gnuhaut@lemmy.ml 4 points 1 week ago* (last edited 1 week ago)

man switch_root

switch_root moves already mounted /proc, /dev, /sys and /run to newroot and makes newroot the new root filesystem and starts init process.

WARNING: switch_root removes recursively all files and directories on the current root filesystem.

If you look at the source code, it uses mount(2) with the MS_MOVE flag to move the /proc, /dev, /sys, /run to the new root, then deletes all the files on the old root fs recursively, then MS_MOVE-mounts the new root over the old one. As the comment in the source code points out:

/* Don't try to unmount the old "/", there's no way to do it. */

This is presumably why it deletes the files on the initrd, because it is a ram disk and the files would be eating up memory if left there.