U disk installation system when the PE can not find the hard drive reason

With a U disk installed system in the process of the individual computer will appear in the PE can not find the phenomenon of hard disk, this is generally the hard drive mode is not set, what is the mode of the hard disk? The meaning of normal, lab and large has long been neglected, and the number of people who can know it is few and far between. So let's give you a brief introduction to the meaning of these three models.

Normal (normal mode) is the earliest IDE way. The BIOS and IDE controllers are accessed in this way without any conversion to the parameters. The maximum number of cylinders supported is 1024, the maximum number of heads is 16, the maximum sector is 63, and the number of bytes per sector is 512. Therefore, the maximum capacity of the hard disk supported by this mode is 528MB (1024*16*63*512), which makes the actual physical space of the hard disk larger than this, but the space that can be accessed is only 528M.

LBA (logical addressing), which increases the disk access space to 8.4GB, the cylinder, head, sector and other parameters set in LBA mode are not physical parameters of the actual hard disk, and the IDE controller converts the hard disk's cylinder, head, sector and other logical addresses into actual physical addresses when accessing the hard disk. The difference between LBA and normal is that the maximum number of heads that can be set is 255 (1024*255*63*512).

LARGE (large hard drive mode), this mode is used when the cylinder of the hard disk exceeds 1024 and is not supported by LBA. The pattern is to divide the number of cylinders by 2, the number of heads multiplied by 2, and the total capacity unchanged. You do not need to change these systems, the serial port and the mouth on the line.