When we use the hard drive, often some strange problems. In order to effectively save the hard drive data, in addition to routinely back up outside of work, but also learn the hard drive fails to save hard drive, or from a bad area to extract useful data, to minimize the extent of the loss. Here I collected a hard drive failure solutions often appear, for your reference, we want to help:
1, the system does not recognize hard drive
System can not boot from the hard drive, boot from A drive can not access C drive, use the CMOS of the automatic monitoring function can not find the existence of the hard disk. Most of these failures appear in the connection cable or IDE ports, hard disk failure is unlikely in itself, can be re-plug hard drive IDE cable or a change to replace the port and cable testing, will soon find fault lies. If the new hard drive is not connected to acceptance, a common reason is the master and slave jumpers on the hard disk, if an IDE hard disk drive line connected the two devices, it is necessary to distinguish the primary from the relationship.
Second, CMOS failures
CMOS in the hard disk drive type is right or not directly affect the normal use. The machines are now supporting "IDE Auto Detect" function, can automatically detect the type of hard disk. When the hard disk type error, or sometimes even unable to start the system, sometimes to start, but will read and write error occurred. Such as CMOS type of hard disk drives smaller than the actual capacity of the drive behind the sector will not be able to read and write, if it is multi-division state the individual partitions will be lost. There is also a major cause of the malfunction, the current logical arguments support the type of IDE hard disk can use "Normal, LBA, Large", etc., if installed in the normal mode data, but in the CMOS of the model to other will be hard to read and write error occurred fault, because the mapping has changed, and will not be able to read the original location of the correct hard drive.
Third, the main boot process due to start trouble
Master boot program is located in the main hard disk boot sector, mainly for testing the correctness of the hard disk partition, and to identify the active partition, is responsible for guiding the right to transfer to the active partition to DOS or other operating systems. This section will not damage the program from the hard disk boot, but boot floppy or CD-ROM drive can read and write later. Way to fix this fault is more simple, use the DOS version of FDISK high most convenient, as with parameters / mbr run-time, will directly replace (override) the hard disk master boot program. In fact the main hard disk boot sector is the program established, FDISK.EXE being a complete hard disk that contains the master boot program. While the DOS version of the update, but the hard disk master boot process has not changed from the DOS 3.x to Windos 95 of the DOS, as long as find a DOS boot disk boot system and run this program can repair.
4, partition table boot failures caused by erroneous
Hard disk partition table errors are serious errors, different errors might lead to different losses. If there is no active partition flag, then the computer will not start. However, after the boot floppy or CD-ROM drive can read and write, reset the active partition by FDISK to repair.
If a partition type of error, can cause the loss of a partition. The fourth partition table for the partition type byte value, the normal bootable DOS partition larger than 32MB of the basic value of 06, while the extended DOS partition value is 05. Many people use this type of value to achieve a single partition of encryption technology, to restore the original value of the correct type can make the partition back to normal.
Partition table, there are other data used to record the start or end address area. These data will result in damage or loss of the chaos of the partition, the available method is to use the backup data to re-write the partition table back, or from other conditions the same type and the same hard disk partition for the partition table data.
NU and other tools can be used to restore tool, the operation very convenient. Of course, can use DEBUG to operate, but easy to operate and has certain risks.
5, area efficient fault error flag
In the hard disk master boot sector there are still an important part, that is, the last two bytes: "55aa", the bytes of the effective symbol for the sector. When from the hard disk, floppy disk or CD-ROM starts, will detect two bytes, if you think hard there, otherwise it would not recognize the hard drive. Here for the whole hard drive encryption technology, the method can be used to restore DEBUG processing. In addition, when the DOS boot sector not leading sign, the system starts to appear as: "Mmissing Operating System". Convenient method is to use the following DOS system common repair methods.
6, DOS boot failure due to start
DOS boot from the DOS boot sector and the main DOS system files. System files include IO.SYS, MSDOS.SYS, COMMAND.COM, which is a DOS shell COMMAND.COM file, similar documents can replace the other, but by default is the essential DOS boot files. DOS in Windows 95 systems carry, MSDOS.SYS is a text file, is to start Windows to the file, but only when the DOS can not start the file. DOS boot error, it can boot from a floppy disk or CD-ROM after using SYS C: command transmission system can repair failures, including boot sector and system files can be automatically repaired to normal.
7, FAT table to read and write failures caused by
FAT table records the hard disk data storage addresses, each file has a FAT chains specify the cluster address stored. FAT table of the damage means the loss of the document. Fortunately DOS FAT system itself provides two tables, if the current use of the FAT table is corrupt, can be used to cover the second repair. However, different specifications of the disk of its FAT table length and the address of the second FAT table is not fixed, so the repair must be correct to find its correct position, a number of tools such as NU itself has such a repair, use also convenience. DEBUG can also be used to achieve this operation, that is, by its m command of the second FAT table to move the first office that you can. If the second FAT table is also damaged, you can not put hard drive back to their original state, but the file data is still stored in hard disk data area, or SCANDISK CHKDSK command can be used to repair and eventually get *. CHK files, This is the FAT chain sector lost data. If it is a text file can be extracted from the full or partial content of the document.
8, table of contents damage caused by lead failure
Catalog table records the name of the file on your hard disk and other data, the most important of which is the starting cluster number of the document. List of tables because there is no automatic backup function, so damage will be lost if the directory number of documents. A kind of method is also used to reduce losses or SCANDISK CHKDSK program to restore the way, from the hard disk to search out the *. CHK files, because the table of contents damage is only missing the first cluster number, each *.. CHK file that is a complete file, its name can be restored to most of the original document.
9, accidentally deleted partition data recovery
When using FDISK to delete the partition, the surface is the hard disk data has completely disappeared, when entered without formatting the hard disk drive will be displayed as invalid. If you understand the working principle of FDISK, FDISK will know only redefined the hard disk master boot sector (sector 0 face 0 1) content, specifically, to delete the partition table information, and any partition hard drive The data are not changed. Can be modeled on the above partition table error repair method, which try to restore the data you can restore the partition table partition and data. If you have formatted the partition, restore partition earlier, according to the following methods of recovery partition data.
10, mistakenly formatted hard drive data recovery
In the DOS version of the state high, formAT formatting by default are set up for the restoration of formatted disk information, is actually the disk of the DOS boot sector, FAT partition table and copy all the contents of the table of contents to disk sector in the last few (rarely used because of the back of the sector), the contents of the data area has not changed. This command can be restored by running the UNformAT. DOS also provides a MIROR command used to record information on the current disk for recovery after formatted or deleted using this method is also more effective.