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However, Microsoft’s MS-DOS is the most widely used, so it has the greatest impact and harm. Only Microsoft with MS-DOS ignored it, resulting in the new version of MS-DOS, such as 6 x、7. Not long after, IBM, Novell and other companies announced that the new version of their DOS had completely solved this problem.
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It is said that as early as 1992, an anti-virus expert named Mike found this problem and reported it to DOS manufacturers with this problem, such as IBM company producing PC-DOS, Novell company producing dr-dos / novelldos, Microsoft company producing MS-DOS, etc.
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It can be seen that this is actually caused by an error during DOS startup. The “logical lock” takes advantage of this by modifying the partition table of the hard disk to make the partition table cycle, that is, point the first logical disk of the extended partition to itself, so that some dos systems can not start because of a life and death cycle when looking for partitions. When DOS is started, the system will automatically search the information of each partition in the hard disk, such as type, size, etc., so that the system can identify the hard disk, assign it to C, D, e, F and other drives, and enable the user to carry out various operations on it. It adopts the technology of “circular partition table”, so that some dos with this error can not be started with any device, including floppy disk and other mobile devices. The so-called “hard disk logic lock” is made by using an error of some dos. Many computer users have seen or heard that when the so-called “logic lock” is in the hard disk, some computers can not be started with floppy disk, hard disk or CD.