The method of removing logical lock of hard disk

Many computer users have seen or heard that, when the so-called "logic lock" on the hard disk, whether it is a floppy disk, hard disk, or CD-ROM can not start some computers. So what exactly is a "logical lock"?

The so-called "hard drive logic lock" is made by using a certain DOS error. It uses the "cyclic partitioning table" technology, so that some of this error dos can not be started with any device, including floppy disk and other mobile devices. When DOS starts, the system will automatically search the hard disk of the various partitions of information, such as type, size, etc., so that the system can identify the hard drive, respectively, assigned to C, D, E, F and other drives, and enable users to carry out a variety of operations. and "logical lock" is the use of this point, by modifying the partition table of the hard disk to make the partition table loop, that is, the first logical disk of the extended partition point to itself, so that some DOS system start to find the partition occurs when the cycle of death loop and can not start.

Visible, this is actually a DOS boot error caused by. It is said that as early as 1992, an anti-virus expert named Mike discovered the problem and reported it to the manufacturer of DOS with this problem, such as IBM, who manufactures Pc-dos, Novell, who manufactures Dr-dos/novelldos, and Microsoft, which produces MS-DOS. Soon after, IBM, Novell and other companies have announced that a new version of its DOS has completely resolved the problem, only MS-DOS Microsoft ignored, resulting in a new version of MS-DOS, such as 6.x, 7.x and so on continue to exist.

However, Microsoft's MS-DOS is the most widely used, so its impact and harm is greatest. Once the user's hard drive is locked by a "logical lock", various Microsoft operating systems, such as MS-DOS 5.x/6.x/7.x/8.0 boot disks, fail to start, creating a false image of a hardware malfunction, and even a lot of the pros are helpless. Because this is very scary, will lead to computer can not be used, so many people have to find ways to prevent and solve. In fact, it is not difficult to solve, the following describes several solutions.

* Start with non-MS-DOS operating system

As you can tell, the "Hard drive logic lock" mainly affects Microsoft's MS-DOS system, so it's OK to use another DOS boot. To this end, I purposely made a "logical lock" on the hard disk for several of the more useful versions of DOS, such as MS-DOS 7.10, Pc-dos 7.10, Dr-dos 7.05, Rom-dos 7.10, FreeDOS beta9, Pts-dos Pro 2000 's boot disk , the results of the start test are as follows:

Pc-dos 7.10 Startup disk: Start all normal;

Dr-dos 7.05 (Version number: 7.10) Startup disk: Start all normal;

Rom-dos 7.10 Startup disk: Start all normal;

FreeDOS beta9 (Version number: 7.10): When starting to display the hard drive error, and completely normal start;

Pts-dos Pro 2000 (version No: 6.90): Start all normal.

Note: All the above DOS are very stable, and both support FAT32 partition and large hard drive, where Rom-dos 7.10 also fully local support long file name, and very good compatibility.

As a result, you can start a hard drive with a "logical lock" with any of the above DOS boot disks, and the disk characters (such as C:) of the hard drive that have been locked after startup are not visible, but various disk partitioning software, such as Norton Disk Editor 2002, Norton Disk Doctor 2002, as well as DOS from the Fdisk program, and so on, can show the locked hard drive, at this time, the above mentioned Diskedit and other tools for this hard disk to view/manual repair operations, can also use some software for automatic repair, such as Netresq, Srctools, To completely remove the "logical lock" on the hard drive, and the data on your hard disk will not be damaged.