zImage: a compressed version of the Linux kernel image that is self-extracting. uImage: an image file that has a U-Boot wrapper (installed by the mkimage utility) that includes the OS type and loader information. A very common practice (e.g. the typical Linux kernel Makefile) is to use a zImage file.
What is zImage and bzImage?
zImage ( make zImage ) This is the old format for small kernels (compressed, below 512KB). At boot, this image gets loaded low in memory (the first 640KB of the RAM). bzImage ( make bzImage )
What are Atags?
The Atags is a list of information about certain aspects of the hardware. This list is created by the bootloader before our kernel is loaded. The bootloader places it at address 0x100, and also passes that address to the kernel through register r2.
What is a Rootfs image?
A rootfs image is just a file system image, that hosts at least an init system. … Note that, whichever file system you choose to use, support for it will have to be compiled into the kernel, so it can be mounted at boot time.
How do you get zImage?
A zImage file contains a compressed Linux kernel image. If it is not available pre-built, you create it by compiling the kernel sources with make zImage . The initramfs created by mkinitcpio is a cpio archive containing the files of an initial ram filesystem that is used at startup.
What is difference between uImage and zImage?
zImage: a compressed version of the Linux kernel image that is self-extracting. uImage: an image file that has a U-Boot wrapper (installed by the mkimage utility) that includes the OS type and loader information.
Why is it called vmlinuz?
The kernel binary on the original UNIX as developed at Bell Labs was called unix. … And because the Linux kernel executable was made into a compressed file and compressed files typically have a z or gz extension on Unix-like systems, the name of the compressed kernel executable became vmlinuz.
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.
Why is Linux kernel compressed?
Traditionally, when creating a bootable kernel image, the kernel is also compressed using gzip, or, since Linux 2.6. … On the SPARC architecture, the vmlinux file is compressed using simple gzip, because the SILO boot loader transparently decompresses gzipped images.
How does Busybox work?
Busybox allows you or programs to perform actions on your phone using Linux (copied from Unix) commands. Android is basically a specialized Linux OS with a Java compatible (Dalvik) machine for running programs.