Lenovo IdeaPad S10 - Manual (Page 167)

Explanation of hard disk capacity
Dear user,
While using your computer, you may discover that the nominal hard disk capacity
indicated is somewhat different from the disk capacity displayed by the operating
system. For example, a nominal 80 GB hard disk will appear as less than 80 GB in the
operating system. This discrepancy is not an error in hard disk installation nor any
other problem, but a normal phenomenon of computers. This phenomenon is
primarily due to the following reasons:
1. Different standards used by the manufacturer and operating system when
calculating hard disk capacity
Hard disk manufacturers use a radix of 1000, i.e. 1 G = 1,000 MB, 1 MB = 1,000
KB, 1 KB = 1,000 bytes. However, when identifying hard disk capacity, operating
systems use a radix of 1024, i.e. 1 GB = 1,024 MB, 1 MB = 1,024 KB, 1 KB = 1,024
bytes. The standard adopted by your computer is that of the hard disk
manufacturers. Since the standards adopted by the hard disk manufacturer and
operating system are different, the hard disk capacity displayed by the operating
system will be different from the nominal hard disk capacity.
For example, if the hard disk is nominally X G, even when it is completely empty,
the capacity displayed by the operating system will be: X Ч 1000 Ч 1000 Ч 1000/
(1024 Ч 1024 Ч 1024) ≈ X × 0.931 G.
If a portion of the hard disk space has been used for some specific purpose, then
the capacity indicated by the operating system will be even less than X × 0.931 G.
2. A portion of the hard disk space is used for specific purposes
Appendix D. Notices 159