I have a number of thumb drives and hard drives. One hard drive I bought was said to be 2TB but its actual capacity is about 1.8 TB. A couple of thumb drives I got say they are 16 GB but on the back say:

1MB = 1,000,000 bytes /
1GB = 1,000,000,000 bytes

This definition is the reason why I've accepted the false advertising on hard drive space, even though conventionally:

1KB = 1024 bytes
1MB = 1024x1024 bytes
1GB = 1024x1024x1024 bytes

and not

1KB = 1000 bytes
1MB = 1000x1000 bytes
1GB = 1000x1000x1000 bytes

As we get to higher levels the amount of space that is lost by this rounding down increases.

But isn't this still false advertising? E.g., in Australia could I get a refund as I was misled in the believe that a thumb/hard drive had the higher capacity?

  • ... Have you bothered to read the letters? – Zizouz212 Mar 22 '16 at 13:14
  • That's the actual value. And they are not lying - they even gave you a definition of the term when in doubt! – Zizouz212 Mar 22 '16 at 13:15

It's not the manufacturers who are wrong. Your definitions of KB, MB, and GB are incorrect. See, for example, NIST. The numbers they are using are not "rounded down," they are the proper standardized definitions of those terms. 1024 bytes is properly termed a kibibyte (or KiB), not a kilobyte. 1024 kibibytes is a mebibyte, MiB. 1024 mebibytes is a gibibyte, GiB. These are defined in an international standard, IEC 80000-13 (part of the ISO series of standards defining units); "kilobyte" refers to 1000 bytes, "megabyte" to 1000000, and "gigabyte" to 1000000000. It's not lying to use units correctly, and that's what the manufacturers are doing.

  • So that means Windows is lying as i have my 16 GB thumbdrive in and it says the capacity is 15,818,031,104 Bytes but on the side it says 14.7 GB, not 14.7 GiB and 14.7 is the approximate value of (((15,818,031,104)/1024)/1024)/1024. – Memor-X Mar 22 '16 at 13:24
  • @Memor-X Windows is incorrect with its definition of GB. That's not on drivemakers. – cpast Mar 22 '16 at 13:30
  • @Memor-X I would say "controversial" or perhaps "old fashioned" rather than "incorrect." The use of the SI prefixes to mean multiples of 1024 predates the development of KiB and the like by some decades. – phoog Mar 22 '16 at 13:50
  • 2
    Whether the definition is incorrect is a red herring. Each gives you a way of knowing how many actual bytes available. The drive manufacturer by their note on the package staying which definitions they are using, and the OS by giving you more detailed info down to the byte if you look for it. – user3851 Mar 22 '16 at 13:53

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