Alternatively, you can use the cpio program with the -p option, because cpio handles device special files correctly, and will not try to copy the contents. If you want to do it the hard way, use ls -l to display the major and minor device numbers for the devices you want, and create them on the diskette using mknod . However the devices are copied, it is worth checking that any special devices you need have been placed on the rescue diskette. For example, ftape uses tape devices, so you will need to copy all of these if you intend to access your floppy tape drive from the bootdisk. Note that one inode is required for each device special file, and inodes can at times be a scarce resource, especially on diskette filesystems.
Many devices are obviously unnecessary on specific systems.
For example, if you do not have SCSI disks you can safely remove all the device files starting with sd . Similarly, if you don't intend to use your serial port then all device files starting with cua can go. This directory must contain a number of configuration files. May be required, but no-one is too sure. Junk that crept in.