This chapter shows how to build the last missing bits of the temporary system: the tools needed by the build machinery of various packages. Now that all circular dependencies have been resolved and the temporary system is already bootable, we can boot it on the target system which is completely isolated from the host operating system used for the build.
For proper operation of the temporary system, some communication with the running kernel must be established. This is done through the so-called Virtual Kernel File Systems, which must be mounted as soon as possible after boot. You may want to check that they are mounted by issuing mount.
All commands in this and following chapters are run as root on the target system, fortunately without access to the host system. Be careful anyway, as if your target system is not fresh new and already contains some important data, it's possible to destroy them with badly formed commands.