Well, this is something that is known and acknowledged in the whole industry.
I quote from Wikipedia:
As of 2007, most consumer hard drives are defined by their gigabyte-range capacities. The true capacity is usually some number above or below the class designation. Although most manufacturers of hard disks and Flash disks define 1 gigabyte as 1,000,000,000 bytes, the computer operating systems used by most users usually calculate a gigabyte by dividing the bytes (whether it is disk capacity, file size, or system RAM) by 1,073,741,824. This distinction is a cause of confusion, especially for people from a non-technical background, as a hard disk with a manufacturer rated capacity of 40 gigabytes may have its capacity reported by the operating system as only 37.2 GB, depending on the type of report.
The difference between SI and binary prefixes is logarithmic â?? in other words, an SI kilobyte is nearly 98% as much as a kibibyte, but a megabyte is under 96% as much as a mebibyte, and a gigabyte is just over 93% as much as a gibibyte. This means that a 500 GB hard disk drive would appear as “465 GB”. As storage sizes get larger and higher units are used, this difference will become more pronounced.
Note that computer memory is addressed in base 2, due to its design, so memory size is always a power of two (or some closely related quantity, for instance 384 MiB = 3Ã?227 bytes). It is thus convenient to work in binary units for RAM. Other computer measurements, like storage hardware size, data transfer rates, clock speeds, operations per second, etc., do not have an inherent base, and are usually presented in decimal units.
As an example, take a hard drive that can store exactly 140Ã?109 or 140 billion bytes after formatting. Generally, operating systems calculate disk and file sizes using binary numbers, so this 140 GB drive would be reported as “130.38 GB”. The result is that there is a significant discrepancy between what the consumer purchased and what their operating system says they have.
Some consumers feel short-changed when they discover the difference, and claim that manufacturers of drives and data transfer devices are using the decimal measurements in an intentionally misleading way to inflate their numbers, though these measurements are the norm in all fields other than computer memory. Several legal disputes have been waged over the confusion. See Binary prefix â?? Legal disputes.
The basis of the problem is of course that the official definition of the SI units is not well known, and some legal settlements include directions for manufacturers to use clearer info, e.g. by stating a hard disk’s size in both GB and GiB.
Thus:
When you purchase 160GB, which is 160,000,000,000 bytes.
You take 160,000,000,000 / 1024 / 1024 / 1024 to be roughly equals to 149.0116119384765625 GB. This amount is reported by the operating system.
And look how much you seemed to be shortchanged:
160 GB - 149.0116119384765625 GB ~= 11 GB
It would be worse for the 320 GB hard disk I intend to purchase, I get 298.023223876953125 GB reported in the Operating System, which is roughly shortchanged of about 22 GB.
This problem has always been there but Western Digital sums it up best by lamenting - Apparently, Plaintiff believes that he could sue an egg company for fraud for labeling a carton of 12 eggs a “dozen,” because some bakers would view a “dozen” as including 13 items.
Wow, quote of the Day!
[I was talking about this to some friends and thought I share with you guys.]
