## Friday, November 20, 2009

### Hard disk capacity is getting smaller

I'm just about to go to Fry's Electronics and get myself a Seagate Barracuda LP 2TB 3.5" SATA 3.0Gb/s Hard Drive -Bare Drive (that link is to the same drive but at NewEgg). I was curious to know how big this 2TB drive would be so I did a quick calculation and discovered that it will be 1.82 TB. As most people know, disk drive manufacturers calculate disk sizes to make them appear bigger than they actually are. They measure a Kb as 1,000 bytes instead of 1,024 bytes.

This caused me to do a little calculation to see what were were getting when sold drive space:

1MB (advertised) = 0.95 MB (actual)

1GB = 0.93 GB

1TB = 0.91 TB

1PB = 0.89 PB

Do you see the progression? they're getting smaller. Eventually that number will be 0.00 Xb.

A PB is a Petabyte which I have always considered to be 1,024^5. However, according to wikipedia I'm wrong and it's 1,000 terabytes and not 1,024 terabytes and a Pebibyte abbreviated as Pi is what I should be using. Also all my other references are apparently wrong and I should be using Mi, Gi, Ti, and Pi as abbreviations.