Initramfs (Initial RAM File System) is a way of providing the Linux kernel with the drivers and other tools needed to mount the real root filesystem at boot time. Use this tag if your question relates to using and controlling initramfs.
During the Linux boot process, an image of the initial root filesystem is loaded into memory along with the kernel by the bootloader. Initramfs (Initial RAM File System) is an archive of this initial root filesystem containing all the drivers and other tools that are needed to mount the real root filesystem.
It is unpacked by the kernel and used to run the init process, including mounting of the real filesystem. In Ubuntu, initramfs images for each kernel are stored in /boot and addressed in /var/lib/initramfs-tools. After updating GRUB bootloader or kernel modules, the image is regenerated by running the update-initramfs command - a task usually automatically performed by the package management system.
