loader is a BTX client as well. I will not describe it here in detail, there is a comprehensive manpage written by Mike Smith, loader(8). The underlying mechanisms and BTX were discussed above.

The main task for the loader is to boot the kernel. When the kernel is loaded into memory, it is being called by the loader:

sys/boot/common/boot.c:
    /* Call the exec handler from the loader matching the kernel */
    module_formats[km->m_loader]->l_exec(km);