RE: data storage terminology

Subject: RE: data storage terminology
From: "Chinell, David F (GE EntSol, Security)" <David -dot- Chinell -at- GE -dot- com>
To: "Sam Lightbourne" <Sam -dot- Lightbourne -at- datacore -dot- com>, <techwr-l -at- lists -dot- techwr-l -dot- com>
Date: Thu, 17 Sep 2009 17:12:12 -0400


If you're following SI conventions the correct prefix is T. In SI
notation, you never pluralize the unit of measure, so:

10 TB

Would be fine.

The MS MoS cautions that if the reader may be unfamiliar with the unit,
you should try to spell it out first in the body text to introduce the

However, while the SI Web pages
( confirm
the use of T as the correct prefix for tera, they add this depressing
sidebar note.

"These SI prefixes refer strictly to powers of 10. They should not be
used to indicate powers of 2 (for example, one kilobit represents 1000
bits and not 1024 bits). The IEC has adopted prefixes for binary powers
in the international standard IEC 60027-2: 2005, third edition, Letter
symbols to be used in electrical technology - Part 2: Telecommunications
and electronics. The names and symbols for the prefixes corresponding to
2^10, 2^20, 2^30, 2^40, 2^50, and 2^60 are, respectively: kibi, Ki;
mebi, Mi; gibi, Gi; tebi, Ti; pebi, Pi; and exbi, Ei. Thus, for example,
one kibibyte would be written: 1 KiB = 210 B = 1024 B, where B denotes a
byte. Although these prefixes are not part of the SI, they should be
used in the field of information technology to avoid the incorrect usage
of the SI prefixes."

This indicates the "correct" abbreviation for terabyte is TiB. However I
can't find much evidence that anyone is using this approach.


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data storage terminology: From: Sam Lightbourne

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