Linux knowledge-Brief Introduction to vmlinuz

Linux knowledge-vmlinuz brief introduction vmlinuz is a bootable and compressed kernel. "Vm" represents "Virtual Memory ". Linux supports Virtual Memory. Unlike earlier operating systems such as DOS, there is a limit of KB memory. Linux can use hard disk space as virtual memory, so it is named "vm ". Vmlinuz is an executable Linux kernel located in/boot/vmlinuz, which is generally a soft link. There are two ways to establish vmlinuz. One is to compile the kernel through "make zImage" to create, and then through: "cp/usr/src/linux-2.4/arch/i386/linux/boot/zImage/boot/vmlinuz" generated. ZImage is suitable for small kernels. It exists for backward compatibility. The second is when the kernel is compiled by the command make bzImage to create, and then through: "cp/usr/src/linux-2.4/arch/i386/linux/boot/bzImage/boot/vmlinuz" generated. BzImage is a compressed kernel image. It should be noted that bzImage is not compressed with bzip2, and bz in bzImage is easy to misunderstand. bz indicates "big zImage ". B In bzImage means "big. Both zImage (vmlinuz) and bzImage (vmlinuz) are compressed using gzip. They are not only a compressed file, but are embedded with gzip decompression code at the beginning of the two files. Therefore, you cannot use gunzip or gzip-dc to unpackage vmlinuz. The kernel file contains a micro gzip used to extract the kernel and boot it. The difference between the two is that the old zImage decompress the kernel to the low-end memory (the first 640 K), and The bzImage decompress the kernel to the high-end memory (more than 1 MB ). If the kernel is small, zImage or bzImage can be used. The two methods guide the same system runtime. BzImage is used for large kernels, and zImage cannot be used. Vmlinux is an uncompressed kernel and vmlinuz is a compressed file of vmlinux. Vmlinux is the ELF file, that is, the most original file compiled. Vmlinuz should be the file zImage compressed by vmlinuz after being OBJCOPY by the ELF File vmlinux and compressed by gzip. It is applicable to the small kernel bzImage which is the file after vmlinuz is compressed by gzip, it is applicable to large kernels. Generally, you cannot use vmlinuz to decompress the package to obtain vmlinux.