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Master the fundamental concepts of the boot process — theory through this focused micro-challenge.
An initramfs is a cpio archive the bootloader loads into memory before the kernel starts. Early kernel code mounts it as a tmpfs root so drivers and scripts can run before the real root disk is available. For example, a typical Linux image ships initramfs-linux.img containing module-loading helpers and init glue that finds the LUKS or LVM root.
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The kernel mounts tmpfs, extracts the cpio archive into rootfs, and executes /init. Dracut-generated images include udev rules to modprobe storage drivers before pivot_root. If /init exits, the kernel panics; keep the process alive until switch_root completes. Inspect an image with lsinitrd or zcat initramfs.img | cpio -itv to see which helpers your distro ships.
You will trace how the bootloader passes an initramfs blob to the kernel and what early /init must accomplish. This exercise requires describing why root-on-LUKS or NFS roots depend on initramfs content before pivot_root.
Simulate initramfs operations in C.
Requirements:
Test:
Three hints are available for this task, revealed one at a time inside the code workspace so you can struggle productively before seeing them.
Every task includes starter code, theory, and hidden tests so you can implement and verify locally in the browser.
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