virtualbox下的ubuntu经常因为各种原因被强制关闭，然后再启动的时候就出现类似错误：

mounting /dev on /root/dev failed: No such file or directorymount:
mounting /sys on /root/sys failed: No such file or directorymount:
mounting /proc on /root/proc failed: No such file or directory
Target file system doesn’t have /sbin/initNo init found.
Try passing init= bootarg
Busybox v1.13.3 (Ubuntu 1:1.13.3-1ubuntu7) built-in shell (ash)
Enter ‘help’ for a list of built-in commands
(initramfs) _

修复办法：

1. 在虚拟光盘添加一个ubuntu12.04的cd映像(10.04的有bug)
2. 从光盘进入系统，也就是（try ubuntu）
3. 进入系统后在终端运行sudo fsck /dev/sda1
4. 一路提示都直接按回车，直至修复完毕
5. 关闭系统，卸掉虚拟光盘的系统映像，重新启动，一切OK！