用戶空間
User space is system memory allocated to running applications. It is often contrasted with kernel space, which is memory allocated to the kernel and the operating system. Separating user space from kernel space protects the system from errant processes that could use up memory required by the operating system (OS).
uImage 和 zImage 的區別
After the kernel compiles (make), it will generate two files, an Image, a zImage, where Image is the kernel image file, and zImage is an image compression file of the kernel. Image is about 4M, and zImage is less than 2M.
So what is uImage? It is a uboot-specific image file. It adds a 64-byte “header” before the zImage, indicating the version, loading position, generation time, size, etc. of the kernel; it is no different from zImage after 0x40.