WD 2T be a data disk

WD Internal Drives Desktop & Mobile Drives
1

I just bought a 2T’s WD to be data disk not system disk

but in computer space are not 2T just only 1.81T 

Is that normal? 

thanks

2

That is correct.  The marketing vs the actual usage is different. It is easier to say 2 Terabytes instead of 1.81 Terabytes.

This is the scale that is used.

  • 1 byte = 8 bits
  • 1 kilobyte (K / Kb) = 2^10 bytes = 1,024 bytes
  • 1 megabyte (M / MB) = 2^20 bytes = 1,048,576 bytes
  • 1 gigabyte (G / GB) = 2^30 bytes = 1,073,741,824 bytes
  • 1 terabyte (T / TB) = 2^40 bytes = 1,099,511,627,776 bytes

So if you took the 1,099,511,627,776 * 2 = 2,199,023,255,552 terabytes then when you format the drive it would read a full 2.0 TB in Windows 7. However for whatever reason they find it easier to design the drive as a straight 2,000,000,000,000 and the conversion drops the 190 GB of data.