For each of these stages and components there are different variations and approaches; for example, GRUB, LILO, SYSLINUX or Loadlin can be used as boot loaders, while the startup scripts can be either traditional init-style, or the system configuration can be performed through modern alternatives such as systemd or Upstart.
对于不同的阶段和组件它们存在不同的变化和途径；比如GRUB、LILO、SYSLINUX或者Loadlin等能被用来当作启动加载器，同时启动脚本可以是传统的init风格，也可以是系统配置能被执行的现代替代方案比如systemd或Upstart。