Troubleshooting system startup

This section discusses reasons why a system that has booted successfully in the past may not boot now. These situations usually occur as a result of a power failure or system panic that corrupts the root filesystem, although configuration changes, hardware failure, and human error can also cause these situations.

If you are performing an installation and your system fails to boot see Chapter 3, ``Troubleshooting the installation''.

If you cannot boot your system:

• Is the system plugged in?

• Are any cables loose, disconnected, or misconnected?

• Are the cable chains terminated properly?

• Does the floppy drive contain a floppy disk that is not a boot floppy disk?

• Has your hard disk developed a bad track? A bad track on the disk can corrupt system files that are required for booting the system.
  See ``Fixing bad tracks and bad blocks on hard disks'' for information on how to recover from this situation.

Many of the problems discussed here relate to missing system files. ``About missing or corrupted system files'' explains what you need to restore files.

These problems are discussed:

• Restoring critical security database files

• System fails to boot or displays ``NO OS'' message

• boot not found

• unix not found

• Cannot load floating point emulator

• Cannot exec /bin/login: No such file or directory

• Cannot open /etc/inittab

• /etc/initscript: /bin/sulogin: not found

• /etc/initscript: /etc/bcheckrc: not found
  

• no utmp entry. You must log in from lowest level -sh

• Fork failed... Resource temporarily unavailable

• System hangs at boot time

• Console keyboard locks up

• Cannot log into console