Each user's hard drive are stored a large number of useful data, while the hard drive is an easy to faulty parts.In order to effectively save the data in the hard disk, hard disk in addition to the preservation of an effective data backup outside of work, but also learn how to save hard disk failure, or extract useful data, to reduce losses to a minimum.
1, the system does not recognize hard drive
Such failures are more common, from the hard disk does not start, can not boot from A drive into the C drive, the use of CMOS in the automatic monitoring function can not be found in the presence of the hard disk.Most of these failures appear in the mouth of the port connector on the cable or IDE hard disk itself, the failure rate of small, can change to re-plug cable or IDE hard drive and cables were replaced by oral test, where failure can be quickly found.If you do not recognize the new hard drive connected, there is a common reason for this is the hard drive from the main line, if the hard disk connected to the IDE's main location, the hard disk to skip the main coils, jumpers usually can not detect the errorhard disk.
2, CMOS failure caused by
CMOS direct impact on the correctness of the normal use of the hard disk, this mainly refers to one of the hard disk type.Fortunately, the machines now support the "IDE auto detect" feature that can automatically detect the hard disk type.When connecting the new hard drive or replace a new hard disk should be set back by this feature type.Of course, some types of motherboards can automatically identify the type of hard disk.When the hard disk type error, and sometimes simply can not start the system, and sometimes be able to start, but it will happen to read and write errors.Such as hard drive type in CMOS is less than the actual hard disk capacity, the hard drive behind the sector will not be able to read and write, if it is a state of the individual multi-partition partition will be lost.There is also a major cause of the malfunction, the current logical arguments support the type of IDE hard disk can be Normal, LBA, Large and so on.If the normal mode, install the data, but to others in the CMOS mode, the hard disk read and write error occurs fault, because the physical geological mapping has changed, and will not be able to read the original location of the correct hard drive.
3, the master boot program startup failure caused by
Hard disk master boot sector is one of the most sensitive parts, including the master boot program is part of it, this section is primarily used to detect the hard disk partition program correctness, and to determine the active partition, is responsible for handing over the leadactive partition DOS or other operating systems.This section will not damage the program from the hard disk boot, but after the soft areas or light areas on the hard drive read and write.Way to fix this fault is more simple version of DOS's fdisk with the most highly convenient, as with the parameter / mbr run, will directly replace (override) the hard disk master boot program.In fact the hard disk master boot sector is the establishment of this program, fdisk.exe into the hard disk that contains a complete master boot program.Although the updated version of DOS, but the hard disk master boot process has not changed from DOS 3.There are currently winDOS 95 x to the DOS, so long as to find a DOS boot disk to start the system and run this program can repair.In addition, other tools like kv300 also has this feature.
4, partition table boot boot failure error
Hard disk partition table errors are serious errors, different errors might lead to different losses.If there is no active partition flag, the computer will not start.However, soft areas or light areas on the hard drive after booting the system to read and write, you can reset the active partition by fdisk to repair.If it is a partition type error, can cause the loss of a partition.The fourth byte of the partition table values for the partition type, the normal bootable DOS partition larger than 32mb is the basic 06, the extended DOS partition value is 05.If the basic DOS partition type to 05 can not start the system, and can not read and write the data.If 06 to DOS does not recognize the types, such as efh, the DOS partition is not a DOS partition that changed, of course, can not read and write.Many people use a single partition realized the value of this type of encryption technology, to restore the original value of the correct type can make the partition back to normal.There are other data in the partition table to record the start or end address of partition.These data will result in damage or loss of the confusion of the Division, generally can not be manually restored, the only way 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 partitiontable data, or other data will result in permanent loss.Master boot sector in the operation, and other software tools can be nu, the operation very convenient, can be directly on the hard disk master boot sector to read and write or edit.Of course, can be debug operation, but the complicated operation and has certain risks.
5, the effective partition of hard disk failure caused the error flag
In the hard disk master boot sector there is also an important part, that is, the last two bytes: 55aah, the word mark for the sector effectively.When from the hard disk, floppy disk or optical zone starts, will detect these two bytes are considered hard if there exists, or it will not recognize the hard drive.This flag will be transferred from the hard disk into the floppy disk rom basic or prompt.Can not be transferred from the floppy disk.Here for the entire hard drive encryption technology.Debug methods can be used for recovery processing.In addition, DOS boot sector is still a sign there, when the DOS boot sector, no boot logo, the system starts to appear as: "missing operating system".The repair method can be used to fix the master boot sector, but addresses a different, more convenient way is to use the DOS system, the following general fixes.
6, DOS boot failure due to start
DOS boot from the DOS boot sector and the main DOS system files.System files include iosys, msdos.sys, command.com, which is a DOS shell command.com file, can replace other similar documents, but the default state is essential DOS boot files.DOS in Windows 95 systems carry, msdos.sys is a text file, is to start the windows to the document.But only do this when starting DOS file.But the DOS boot error, you can boot from a floppy disk or CD-ROM, then use the sys c: to repair transmission system failures, including boot sector and system files can be automatically restored to normal.
7, fat table to read and write due to failure
record of the hard fat table data storage addresses, each file has a set of connection to specify its stored fat chain cluster address.fat contents of the file table means the loss of damage.Fortunately DOS system itself provides two fat table, if the current use of the fat table is corrupt, can be used to cover the second repair.However, due to different specifications of the disk of its fat length of the table and the address of the second fat table is not fixed, so the repair must be properly find its correct position, by a number of tools such as nu such repair itself, using alsovery convenient.Debug can be used to achieve this operation, that is, using the m command of the second fat at the table can be moved to the first table.If the second table is also damaged fat, you can not put the hard disk back to its original state, but the file's data is still stored in the hard disk data area, can use the command chkdsk or scandisk to repair, and ultimately get *.chk file, which is the loss of fat chain sector data.If it is a text file can be extracted from the full document can be merged, if it is a binary data file, it is difficult to restore a complete file.
8, table of contents damage caused by lead failure
Table of records with the hard disk file name and other data, the most important of which is the starting cluster number of the file, directory table because there is no automatic backup function, so damage will be lost if the directory number of files.A method is also used to reduce the loss of chkdsk or scandisk programs above methods to search out from the hard disk chk files, table of contents damaged by the cluster number is the first loss for the damage in case of fat formed chk files are generallymore complete file data, each chk file that is a complete file, to restore its original name to most of the documents.
9, accidentally deleted partition data recovery
When using fdisk to delete the partition, the surface phenomenon is the data in the hard disk has completely disappeared, without formatting the hard disk will be displayed when entering an invalid drive.If you understand the working principle of fdisk, you know, fdisk the hard drive just to rewrite the master boot sector (sector 1 0 0 plane) of the content.Specifically, to delete the hard disk partition table information, and any hard disk partition data are not changed, you can copy the partition table fix errors that find ways to partition table data recovery partition that can restore the original data, butonly limited to the addition or re-partition after partition.If you have the partition formatted with the format, the earlier recovery partition, in accordance with the following methods of data recovery partition.
10, mistakenly formatted hard disk data recovery
High in the DOS version of state, the format operation format have been established under the default format for disk information recovery, in fact, the disk DOS boot sector, fat partition table and copy all the contents of the directory table todisk sectors in the last few (rarely used because of the back of the sector), the contents of the data area has not changed.This by running the "unformat c:" to restore the original file allocation table and the table of contents, thus completing the recovery disk information.Another DOS command also provides a miror disk for record of the current information for the recovery of formatted or deleted using this method is also more effective.