Computer data recovery,
The hard disk is the place where data is stored in the computer, and it is also the reason why the computer exists. A computer without a hard disk can only mean that it is just a program, but there is no storage space. First of all, data recovery is not limited to hard drives, but can include data recovery from other media storages.
When we store a file on the hard disk, the system will first write the file name and size in the file allocation table, and continue to write the file content in the data area based on the free space in the data area. starting position. Then start writing the actual content of the file to the data area. Only then is the file storage operation completed. Computer maintenance at Hangzhou North Bus Station.
The deletion operation is very simple. When we need to delete a file, the system just writes a delete mark in front of the file in the file allocation table, indicating that the file has been deleted and the space it occupies has been "Release", other files can use the space it occupies. Therefore, when we delete a file and want to retrieve it (data recovery), we only need to use a tool to remove the deletion mark, and the data will be recovered. Of course, the premise is that no new files are written and the space occupied by the file is not overwritten by new content.
The formatting operation is similar to deletion. Both operations only operate the file allocation table. However, formatting adds delete marks to all files, or simply clears the file allocation table. The system will consider that the hard disk partition does not exist. Any content. The formatting operation does not perform any operations on the data area. The directory is empty but the content is still there. With the help of data recovery knowledge and corresponding tools, the data can still be recovered.
Because of the storage characteristics of disks, when we no longer need the data on the hard disk, the data is not taken away. When deleting, the system only writes a deletion mark on the file. Formatting and low-level formatting also overwrite the data with the number 0 as the content on the disk. This is overwriting.
After a file is marked for deletion, the space occupied by it may be overwritten with new content when a new file is written. Although the deleted file name is still there, the space content it points to in the data area has been overwritten and changed, and what is restored will be error and exception content. Similarly, the space occupied by file information with deletion marks in the file allocation table may be overwritten by the new file name file information, and the file name will no longer exist.
When a partition is formatted and new content is copied, the new data only covers the space in front of the partition and removes the space occupied by the new content. The unordered content in the data area of ??the remaining space of the partition still has It may be reorganized and the data recovered.
Similarly, for data loss caused by cloning, one-click recovery, system restore, etc., as long as the space occupied by the new data is less than the space capacity before the damage, U disk data recovery, data recovery engineers may be able to recover what you want. Partitions and data.
Hard disk soft failure: system failure: the system cannot start normally, password or permission is lost, partition table is lost, BOOT area is lost, MBR is lost; file loss: misoperation, misformatting, miscloning, misdeletion , mistaken partition, virus damage, hacker attack, PQ operation failure, etc.; file damage: damaged Office series Word, Excel, Access, PowerPoint files Oracle database file repair, Foxbase/foxpro dbf database file repair; damaged email Outlook Express Repair of dbx files, Outlook pst files; repair of damaged MPEG, asf, RM and other media files.
CMOS does not recognize the disk; there is often a clicking sound of the magnetic head hitting; the motor does not rotate, and there is no sound after powering on; misalignment of the magnetic head causes errors in reading and writing data, what should I do if the hard disk is broken 431; difficulty in starting, Frequent crashes, formatting failures, and difficulty in reading and writing; The self-test is normal, but the hard drive cannot be found in the disk management; The circuit board has obvious burn marks, etc.
Disk physical failure classification: Disk body failure: magnetic head burnout, magnetic head aging, magnetic head chip damage, motor damage, magnetic head offset, zero track failure, a large number of bad fans, disk scratches, magnetic group deformation; Circuit board failure: circuit board Damage, chip burnout, broken pins and wires. Firmware information is lost, firmware is damaged, etc.
U disk, USB flash drive, XD card, SD card, CF card, MEMORY STICK, SM card, MMC card, MP3, MP4, memory stick, digital camera, DV, micro hard drive, document repair and recovery Methods, CDs, floppy disks and other types of storage devices. When data media such as hard disks, removable disks, flash disks, SD cards, CF cards, etc. are damaged or circuit board failures, magnetic head offsets, disk scratches, etc. occur, open-body replacement, loading, positioning and other methods are used to repair the data.
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