Why is the hard disk 80G but actually only 74G

The capacity algorithm of the hard disk manufacturer for the hard disk is 1000, and the nominal capacity of the hard disk is 80G, which is converted into bytes: 80 x 1000 x 1000 x 1000=8000000000000 bytes.

And what about the actual capacity: yes.

80000000000 1024 1024 1024=This tells you that your hard drive is actually in accordance with the norm.

Hard disk capacity is one of the most important parameters of hard disk, we often find such a problem when buying and using hard disks The same disk on different machines or using different test software reports different capacities, but they are not greater than the nominal capacity of the hard disk, this problem is more obvious on large-capacity hard disks, for example, the nominal disk is often only the capacity after installation and formatting. The main reason for this is that manufacturers generally calculate capacity at 1000K bytes per megabyte, while most motherboards use 1048K for BIOS and test software. This results in a difference of about 5 per cent.

The capacity of a hard disk is divided into the physical disk capacity calculated purely by the number of heads, cylinders and other physical parameters, and the actual available space after partitioning, formatting, and other operations. In addition, selecting different working modes (norma, lba, large) in the CMOS can also cause capacity inconsistencies. Due to the influence of these factors, it is generally normal for there to be a gap of about 5%-10% between the test capacity of the hard disk and the nominal capacity.

The 2nd floor is right, but one more point.

The hard disk itself has bad bad pixels and red dots, which is where the head cannot read the hard disk normally. But not much. Hard drives are formatted at a low level before they leave the factory, in order to shield out areas that are not working properly or are slow to read.

In fact, according to the algorithm on the 2nd floor, each "80" g hard disk is, but this is not the case, there are some small dots, and they are not the same. This is the difference that comes from the low level. This is also normal and unavoidable.

The landlord can use it with confidence.

Now it's all the same, 250GB only.

This is because the base system chosen by hard drive manufacturers is not binary, but decimal.

Hard disk capacity, the average manufacturer always uses a decimal count. Generally, the operating system of a computer uses binary counting, so it is often found that the capacity of the hard disk seen in the computer is smaller than the actual available capacity on the hard disk, for example, a 20GB hard disk is only displayed.

Particularly misleading is the case of floppy disks. The 720kb floppy disk is 720*1024 digits and the values are often used in 2 hexadecimal numbers (in information science, such a hexadecimal number is also called one), while the floppy disk is inexplicably a number of digits is often used in two hexadecimal numbers (in information science, such a hexadecimal number is also called one), that is, it is not all decimal nor all binary.

For example, if you buy a 40GB hard drive, but the actual usability may only be 38GB, why is this? The reasons can be explained in the following aspects:

Manufacturers generally calculate capacity at 1000K bytes per megabyte, while most motherboards use 1048K as one megabyte for BIOS and test software. This results in a difference of about 5 per cent.

The capacity of the hard disk is divided into the physical disk capacity calculated purely by the number of heads, the number of cylinders and other physical parameters, and the actual available space after partitioning, formatting, etc., and the capacity of the hard disk is not the same under different operating systems.

Selecting different working modes (normal, lba, large) in CMOS may also cause capacity inconsistencies.

Due to the influence of these factors, generally speaking, it should be normal for there to be a gap of about 5%-10% between the test capacity of the hard disk and the nominal capacity.

Manufacturer calculation method: 80g 80 * 1000m 80 * 1000 * 1000k 80 * 1000 * 1000 * 1000b

Computer conversion to: (80*1000*1000*1000)b (80*1000*1000*1000) g

Probably only.

The base system that hardware manufacturers follow is 1000

That is, 1GB = 1000MB 1MB = 1000KB 1KB = 1000B

The base system of the computer system is 1024

That is, 1GB = 1024MB 1MB = 1024KB 1KB = 1024B

So the so-called 750g hard drive.

750g=750 000mb=750 000 000kb=750 000 000 000b

After being recognized by the computer system, it is converted according to the 1024 base system

750 000 000 000b÷1024=732 421 875kb

732 421 875kb÷1024=715715