1, the system does not recognize the hard disk
Can not start from the hard disk from the A disk can not boot into the C drive, use the CMOS the automatic monitoring function can not be found in the presence of the hard disk. Most of these failures appear in the connecting cable or IDE port on the mouth, the hard disk itself is very small failure rate and can be re-plug hard drive cable or a change of IDE port and cable to replace the test, can quickly find fault lies. If the new hard drive connected to the non-recognition, there is a common reason for this is the main hard disk from the line, if the hard disk drive connected to the IDE’s main location, then the hard drive-based disk-to jump, jumper error generally can not be detected the hard disk.
2, CMOS failure caused by
CMOS direct impact on the correctness of the normal use of the hard disk, here mainly refers to the type in which the hard disk. Fortunately, the machines now support the “IDE auto detect” feature that can automatically detect the hard disk type. When you connect a new hard drive or replace a new hard disk by this function must be re-set type. Of course, some types of motherboards can automatically identify the type of hard drives. When the hard disk type error, and sometimes simply can not start the system, and sometimes be able to start, but it will read and write error occurred. Such as CMOS, the type of hard drive is less than the actual hard disk capacity, then the hard drive behind the sector will not be able to read and write, if it is multi-regional state of the individual partitions will be lost. There is also a major cause of the malfunction, since the current logical arguments support the type of IDE hard disk can be used Normal, LBA, Large and so on. If the normal mode, installed the data, but in the CMOS, replaced by other models, the hard disk read and write errors occur failure, because of its 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 is causing the boot failure
Hard disk master boot sector is one of the most sensitive parts, one of the primary boot program is a part of it, this section is primarily used to detect the hard disk partition program correctness, and to determine active partition, is responsible for guiding the right to transferred to the active partition to DOS or other operating systems. This section will be unable to process damaged boot from the hard drive, but after the soft areas or light areas on the hard drive can read and write. Ways to fix this fault is more simple, the use of high version of the DOS-fdisk the most convenient, as with parameters / mbr run-time will have a direct replacement (rewritable) hard disk master boot program. In fact the hard disk master boot sector is the establishment of this program, fdisk. exe into a complete hard disk that contains the master boot program. While the DOS version of the constantly updated, but the hard disk master boot process has not changed from DOS 3. x to the present winDOS 95 of the DOS, so long as to find a DOS boot disk to start the system and run this program can be repaired. In addition, other tools, like kv300 also have this feature.
4, partition table boot boot failure error
The hard disk partition table errors are serious errors, different errors might lead to different types of losses. If there is no active partition flag, then the computer does not start. However, the soft areas or light areas on the hard disk after boot the system read and write, through fdisk to reset the active partition to be repaired. If it is a partition type of error could result in the loss of a partition. The fourth partition table for the partition type byte value, the normal bootable DOS partition larger than 32mb the basic value of 06, while 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 data on them. If DOS does not recognize 06 types of change, such as efh, the DOS Partition that change is not a DOS partition, of course, can not read and write. Many people take advantage of this type of value is to achieve a single partition encryption technology to restore the original values of the right type can make the partition back to normal. The partition table there are other data are used to record the start or termination of the address of partition. These data will result in damage to the partition of the confusion or loss of, generally can not be manually restored, the only way is to backup the data to re-write the partition table back, or from other conditions the same type and the same hard disk partition to obtain data on the partition table, otherwise will result in permanent loss of other data. In the master boot sector to do so, nu can use tools such as software, the operation is very convenient and can be directly on the hard disk master boot sector to read and write or edit. Of course, debug can be used to operate, but the operation cumbersome and has certain risks.
5, area of effective symbol errors caused by hard disk failure
In the hard disk master boot sector there are still an important part, that is its last two bytes: 55aah, this word for the sector and effective logo. When from the hard disk, floppy disk or optical zone starts, will detect these two bytes, if there think there is a hard disk exists, otherwise it would not recognize the hard disk. This flag will be transferred from the hard disk boot rom basic or tip into the floppy disk. Can not boot from a floppy disk into the hard disk. Here can be used for the entire hard drive encryption technology. Debug methods can be used to resume processing. In addition, DOS boot sector is still such a flag is present, when the DOS boot sector not leading marks, the system starts will appear as: “missing operating system”. Of its repair methods available to the primary boot sector repair methods, but addresses a different, more convenient way is to use the following DOS system, a common repair method.
6, DOS boot boot failures caused by
DOS boot system is mainly from the DOS boot sector and the DOS system files. System files include iosys, msdos.sys, command.com, which is a DOS shell command.com file, can be used to 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 windows to document. But only when you can not boot DOS file. But the DOS boot error, it can boot from a floppy disk or CD-ROM, then use the sys c: transmission system failures can be repaired, including the 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 set of connection to specify its stored fat chain cluster address. fat content of the document the table means that the loss of damage. Fortunately, the DOS system itself offers two fat tables, if the current use of the fat table is damaged, can be used to cover the second repair. However, due to different specifications of the disk of its fat table length and the second fat tables do not have fixed addresses, so the repair must be correct to find its correct position, by a number of tools, such as nu and others who have such a repair function, use was also very convenient. Debug can also be used to achieve this operation, that is using its m command of the second fat at the table can be moved to the first table. If the second fat table also damaged, you can not put the hard disk back to its original state, but the file data is still stored in the hard disk data area, can use the command chkdsk or scandisk to repair and eventually get *. chk files, this 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 to guide the damage caused failure
Table of Contents record the name of the file on your hard disk and other data, the most important one is the starting cluster number of the document, the directory table because there is no automatic backup feature, so if the directory is damaged a large number of documents will be lost. Of a method also used to reduce the loss of the above method of chkdsk or scandisk programs from the hard drive search out the chk files, table of contents damaged by the cluster number is the first loss, in the case of fat for the damage formed chk files are generally more complete file data, each one chk file that is a complete document, its original name changed to restore most of the documents.
9, accidentally deleted partition data recovery
When using fdisk to delete the hard disk partition, the superficial is the hard drive data has completely disappeared, without formatting the hard disk will be displayed when entering an invalid drive. If you know fdisk works, you know, fdisk the hard drive just to rewrite the master boot sector (sector 0 face 0 1) in content. Specifically, that is to remove the hard disk partition table information, while the hard disk of any partition of data are not changed, can be modeled the above-mentioned repair partition table wrong approach, that is to find ways to restore the partition table data can be restored the original sub – area that is data, but only limited to the addition or re-partition after the partition. If you already have on the partition formatted with the format, after an earlier recovery partition, in accordance with the following methods of data recovery partition.
10, mistakenly formatted hard disk data recovery
In the DOS version of the high state, the formatting operation format in the default state, have been established for recovery formatted disk information, is actually the disk DOS boot sector, fat partition table and copy all the contents of the table of contents to the last few sectors of the disk (because the latter sector is rarely used), while the contents of the data area has not changed. This by running the “unformat c:” you can restore the original file allocation table and the table of contents, thus completing the hard drive information recovery. Another DOS also provides a miror disk command is used to record the current information for the formatted or deleted after the resumption of the use of this method is also more effective
