Where is the missing hard disk space in the Win7/Win8 computer?

When you buy a 500GB hard drive, after turning on the computer and seeing that the hard disk space displayed by the system is only 440g, you will be very confused about where the rest of the storage space is running.
There are several main reasons why the system shows the wrong space available. For example: there are hidden invisible files, hidden recovery partitions created by the manufacturer, and so on.
Why does the hard disk display space not as big as the manufacturer claims? If you have ever noticed the hard drive, USB flash drive or other storage devices, you will find that the display space is always not as large as claimed.
For hard disk manufacturers, 1KB = 1000Bytes, 1MB = 1000KB, 1GB = 1000MB. That is to say, if a hard disk is said to be 500GB, it actually contains 500*1000*1000*1000=500,000,000,000 Bytes. The manufacturer's 500GB hard drive size is calculated this way.

However, the manufacturer of RAM uses not 1000, but 1024. The memory conversion mechanism is like this: 1KB=1024Bytes, 1MB=1024KB, 1GB=1024MB. Let's reverse the calculation of 500,000,000,000 Bytes in 1024 to calculate how many GB.
500,000,000,000 /(1024 * 1024 * 1024) = 465.66GB
In the Windows system, the data conversion unit is always used 1024, which contradicts the hardware manufacturer's 1000, resulting in the conversion There was a deviation. This will lead to the gap of 35GB.
Why is the remaining space displayed on your computer incorrect?
If you notice the amount of free space on your hard drive partition, you may feel a bit strange. If you want to delve into it, right click on the C drive and you will see the disk space marked as used. In the image below, the space used contains 279GB of files.

However, when you circle all the files in the C drive (including all hidden files and system files), right click and select Properties. You will find that the size of the space occupied by all of these folders does not match what you just saw. Looking at the figure below, we learned that all the files occupy 272GB of disk space, but the actual disk space has already used 279GB, so where is the difference of 7GB?

Originally, certain types of files were not displayed in the Explorer. These invisible files include system restore points and previous versions of some files. If you want to see how much space these invisible files occupy in each partition, you can run the command prompt to see what happens. It is important to note that you must be running as an administrator. The specific operation is as follows:
1. Win+R opens and runs, enter cmd to open the command prompt
2. Enter the command vssadmin list shadowstorage

We can see that there is about 9GB of storage space (Used Shadow Copy Storage space) is occupied by these invisible files, and the above mentioned is more than 7GB, but we are roughly estimated by rounding, so this calculation should be just right.
Let's talk about hidden partitions
Usually the computer itself will contain a hidden restore partition, you can use the system's own disk manager to view.
As shown in the figure below, almost 11GB of hard disk space is allocated to a hidden restore partition.

Through this article, everyone has a clear understanding of the reasons for the lack of hard disk space.