Initrd and/or initramfs is used to load temporary root file system into RAM or system memory hence its named like initial RAM Disk/FS.
What is initramfs in Linux?
initramfs is the solution introduced for the 2.6 Linux kernel series. … This means that firmware files are available before in-kernel drivers load. The userspace init is called instead of prepare_namespace. All finding of the root device, and md setup happens in userspace.
What is the difference between initrd and initramfs in Linux?
Both initrd and ramfs are zipped at compile time, but the difference is, initrd is a block device unpacked to be mounted by the kernel at booting, while ramfs is unpacked via cpio into memory.
What is initrd in Linux?
The initial RAM disk (initrd) is an initial root file system that is mounted prior to when the real root file system is available. The initrd is bound to the kernel and loaded as part of the kernel boot procedure.
What is the use of initramfs in Linux?
The only purpose of an initramfs is to mount the root filesystem. The initramfs is a complete set of directories that you would find on a normal root filesystem. It is bundled into a single cpio archive and compressed with one of several compression algorithms.
What are the run levels in Linux?
A runlevel is an operating state on a Unix and Unix-based operating system that is preset on the Linux-based system.
…
runlevel.
| Runlevel 0 | shuts down the system |
|---|---|
| Runlevel 1 | single-user mode |
| Runlevel 2 | multi-user mode without networking |
| Runlevel 3 | multi-user mode with networking |
| Runlevel 4 | user-definable |
What is Vmlinuz in Linux?
vmlinuz is the name of the Linux kernel executable. … vmlinuz is a compressed Linux kernel, and it is bootable. Bootable means that it is capable of loading the operating system into memory so that the computer becomes usable and application programs can be run.
What is bzImage in Linux?
The bzImage is the compressed kernel image created with command ‘make bzImage’ during kernel compile. It important to note that bzImage is not compressed with bzip2 !! The name bz in bzImage is misleading!! It stands for “Big Zimage”. The “b” in bzImage is “big”.
Why do we need initrd?
The kernel almost certainly will have been passed an initial RAM disk image (usually called “initrd”) by the boot loader. This is needed to provide needed device-special files in /dev, as devices are now dymanically created by the udev daemon which is only started during the middle of the boot sequence.
Where is the initrd file in Linux?
Afterwards, a new root file system can be mounted from a different device. The previous root (from initrd) is then moved to a directory and can be subsequently unmounted. The initrd files are usually in /boot directory, named /boot/initrd. img-kversion with a /initrd.