Adding 4TB - total storage volume not increased

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StephenB wrote:

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It's been this way so long, I'm not sure who started it.  I recall (many years ago) that 1024 multiples were used in early PCs to avoid the divide (using a right shift instead).  Though that is anecdotal, and might well be wrong.  Though of course 1024 is the logical unit for RAM.

  

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RAM uses multiples of 1024 because there are physical address lines, so the total number of locations must be a power of two (a round number in binary) since each line has two possible states (0 and 1).  So it only made sense that a Kilo, Mega, Giga, etc. would be a multiple of 1024 (an even power of 2) instead of 1000.  This was established before hard drives even existed by general usage, not by actual standard.  The shift instead of divide by two has similar roots (two states for each location vs, two states for each address line), but they are not hard linked.  

Hard drives have no similar physical restriction.  I remember 17 sectors per track being common as 5.25" hard drives became mainstream, but that varied some between manufacturers.  In the very early years, some manufacturers used multiples of 1024 for drives as well, but their drives "looked smaller" than the competition that used multiples of 1000, so multiples of 1000 became the norm (as well as folllowing the IEC standard, where multiples of 1024 did not).  Rounding drive size up instead of using fractional sizes also became the norm.  These and the "raw vs, formatted" capacity all add to the confusion of just how much a drive will hold.  The bottom line is the drive manufaturers all want their drives to advertise as being as large as they can get away with.

In 1999, the IEC decided enough was enough and invented (or at least standardized) the KiB, GiB, TiB, etc. for binary multiples.  Computers were now mainstream, and the old "industry standards" were confusing to the general populous, especially since that extra 24 doesn't actually "add up", it multiplies.  The difference was really staring to show with TB=1000x1000x1000x1000 vs. TiB=1024x1024x1024x1024.  But except to explain the difference between the size of drives and RAM, the "KiB", "GiB", "TiB", etc. have yet to become commonly used in the electronics industry.  1024 bytes of RAM is still a "K" not a "Ki" pretty much everywhere I look.  Microsoft is just following the crowd (or stagnating with it, I suppose), and the confusion persists.  Blame old guys (and gals) like me and Bill Gates (though he's out of the game now) for this.

Here is a good reference: Prefixes for binary multiples