UNIX system faults and solutions (1)

Fault 1

Boot not found cannot open Stage 1 boot failure: error loading hd (40)/boot.

Analysis: This indicates that the Boot file in the root directory of the system is lost. Boot is an interactive program used to load and execute UNIX programs. It is mainly used to load and execute the core of UNIX operating systems. During the Boot process, boot reads/etc/default/Boot, displays the boot process information, loads and runs/unix. Therefore, if the Boot file is damaged, the system Boot will fail.

Solution: 1. Insert the Boot disk into the drive and re-power the machine. Boot starts from the Boot disk;

2. Press hd (40)/unix in the system boot prompt. This command is used to mount the UNIX core from the hard disk. Enter the Root password to enter the single-user mode. a Super User prompt is displayed #;

3. Run the command to install the Boot disk on the hard disk, mount/dev/fd0135ds18/mnt, and run the command cp/mnt/boot/to restore the Boot file under the root directory of the hard disk;

4. Run the umount/dev/fd0135ds18 command to detach the Boot disk from the hard disk;

5. Press haltsys to shut down the system, and then take out the Boot disk. Then, the fault is rectified and the system can be properly guided;

6. Enter the Super User after the system is properly guided, and change the owner and group of the/boot file to the bin defined by the system.

Fault 2

After the host is powered on, the following information is displayed on the console screen: unix not found, and then the host crashes.

Analysis: This indicates that the UNIX core is lost. Because/unix contains the core and unix files are damaged, the system cannot mount the parallel kernel, resulting in a crash.

Solution: 1. Insert the Boot disk into the drive and re-power the machine. Boot starts from the Boot disk;

2. type fd (64) unix root = hd (40) swap = hd (41) pipe = hd (40) or Type fd (64) only) or unix. This command is used to mount the UNIX core from the Boot disk, and then enter the Root password to enter the single-user mode. a Super User prompt is displayed #;

3. Run the mount/dev/fd0135ds18/mnt command to install the Boot disk on the hard disk. Then run the command cp/mnt/unix/to restore the unix files in the root directory of the hard disk;

4. Run the umount/dev/fd0135ds18 command to detach the Boot disk from the hard disk;

5. Type haltsys to shut down the system and take out the Boot disk. The fault is rectified and the system can be properly guided;

6. Enter the Super User after the system is properly guided, and change the owner and group of/unix files to the bin and mem defined by the system.

Fault 3

After the machine is powered on, enter the Enter key at the system boot prompt. Many error messages, such as INIT: command exec/etc/brc 1>/dev/console 2> & 1 failed to execute, errno = 9 (exec of shell failed )...

Analysis: This indicates that the system/bin/sh file is damaged or lost. Because sh is an interpreter of Shell standards, Job control, and restrictive commands, damage or loss of this file will cause the system to fail to start.

Solution: 1. insert the Boot disk into the drive and turn on the power again. Press the Enter key at the system Boot prompt. When prompted to insert the Root disk, remove the Boot and insert the Root disk, in this way, the system is all guided by the emergency boot disk until the prompt appears #;