Booting Issues

Q. Some Resons for System not booting?
Ans :
1. May be auto-boot is not set to true
Soln: Use printenv to see whether auto-boot is true or false , if it is false . change the value using Setenv ,
Eg: ok setenv auto-boot?true

2. May be boot block corrupted
Soln: Boot block on the hard disk is corrupted .Boot the system in single user mode with cdrom
Ok boot cdrom -s
#installboot /usr/platform/`uname -i`/lib/fs/ufs/bootblk /dev/rdsk/c0t3d0s0
3. bootblk: can’t find the boot program
Soln: ufsboot in Solaris .Either ufsboot is missing or corrupted . In such cases it can be restored from the cdrom after booting from cdrom & mounting the hard disk
cp /platform/`uname -i`/ufsboot /mnt/platform/`uname -i`

4. boot: cannot open kernel/unix
soln: Kernel directory or unix kernel file in this directory is not found .Probably deleted during fsck or deleted by mistake. Copy it from the cdrom or restore from the backup tape.# cp /platform/`uname -i`/kernel/unix /mnt/platform/`uname -i`/kernel
5.Cannot open /etc/path_to_instSoln: System can not find the /etc/path_to_install file .It might be missing or corrupted and needs to be rebuildTo rebuild this file boot the system with -ar option :ok>boot -arPress enter to select default values for the questions asked during booting and select yes to rebuild /etc/path_to_installThe /etc/path_to_inst on your system does not exist or is empty. Do you want to rebuild this file [n]? ysystem will continue booting after rebuilding the file.
6. /etc/system file missing?
Soln: ok boot -as and it ask for question , if you have backup file , give the path of the file else
Give /dev/null it will take default system values and reboot the system
Note: previously modified parameters will not effect.
7. My Solaris unable to boot it stops at grub> prompt even tried couple of time reinstalling.Earlier it was working fine with same DVD. After i did experiment in fdisk I am facing this problem.
Ans: Ram failed
8. i got Grub error when i am booting my personal system it displaced errornumber 18 how can solve this any one can guide me
Soln: First, Boot through intel solaris CD and choose option No:6 , it will drop to the shell. mount the root slice to /a , and perform /sbin/installgrub /boot/grub/stage1 /boot/grub/stage2 /dev/rdsk/CXDXTXS0.Also perform an FSCK to the root filesystem

9.if you cannot find the soln , why system is not booting?
Ans: go to /var/adm/messages and /etc/log/syslog
Note: /etc/syslog.conf is a configuration file-------àusing this we can manage syslog