Com 226 comp trouble shooting II theory book
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| Test 624 Hard Drives Drive troubleshooting has the potential of destroying any data on the drives. Before attempting to troubleshoot hard-disk problems, be sure to backup as much of the drive as possible. If no backup is available, do not repartition or reformat the drive unless absolutely necessary, and all other possible alternatives have been exhausted. the drive and drive controller. If the controller responds, but the drive does not, try repartitioning and reformatting the hard drive. If the drive still doesn’t respond, replace the hard drive outright. If the controller doesn’t respond, replace the hard-drive controller. Symptom 17-3. One or more sub-directories appear lost or damaged Both the root directory of a drive and its FAT contain references to sub-directories. If data in either the root directory or file allocation table is corrupt, one or more sub-directories might be inaccessible by the drive. Try repairing the drive’s directory structure. Use DISKFIX (with PC Tools) or SCANDISK (with DOS 6.2 or later) to check the disk’s directory structure for problems. Symptom 17-4. Errors occur during drive reads or writes Magnetic information does not last forever, and sector ID information can gradually degrade to a point where you encounter file errors. Start by checking for file structure problems on the drive. Use a utility, such as DISKFIX or SCANDISK, to examine the drive and search for bad sectors. If a failed sector contains part of an .EXE or COM file, that file is now corrupt and should be restored from a backup. If you cannot isolate file problems, you might need to consider a Low-Level (LL) format. This is an ideal solution because LL formatting rewrites sector ID information, but the sophistication of today’s drives makes LL formatting almost impossible. If the drive manufacturer provides a drive preparation utility, you should backup the drive, run the utility, FDISK, FORMAT, and restore the drive. Symptom 17-5. The hard drive was formatted accidentally A high-level format does not actually destroy data, but rather it clears the filenames and locations kept in the root directory and FAT— this prevents DOS from finding those files. You will need to recover those files. Use a utility, such as UNFORMAT (with PC Tools, which can reconstruct root directory and FAT data contained in a MIRROR file. This is not always a perfect process and you might not be able to recover all files. Symptom 17-6. A file has been deleted accidentally Mistyping or forgetting to add a drive specification can accidentally erase files from places you did not intend to erase. You can often recover those files if you act quickly. Use a utility, such as UNDELETE (with PC Tools and DOS, to restore the deleted file. This is not always a perfect process and you might not be able to recover every file. Symptom 17-7. The hard drive’s root directory is damaged A faulty root directory can cripple the entire disk, rendering all sub-directories inaccessible. You might be able to recover the root directory structure. Use a utility, such as DISKFIX (with PC Tools, to reconstruct the damaged FATs and directories. If you have been running MIRROR, DISKFIX should be able to perform a very reliable recovery. You might also try other recovery Download 1.89 Mb. Share with your friends:
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