It apparent from the context of the article, that the author is not aware of
the existence of the binary prefixes.  Maybe Jim, since you seemed to be
some type of authority on standards, it may be beneficial if you introduced
to the people at Plextor the binary prefixes and explain that the confusion
disappears when the correct prefix is applied.

I see nothing wrong with a product being labeled with both prefixes.
Example:

4.7 GB (4.38 GiB).

This way they satisfy both sides and stay technically correct.

It is just a matter of getting the people like Microsoft to add the "i" into
their symbol code so that gibi is seen where 2^30 is the intended meaning.
Now that can't be too difficult, or is it?

Euric

----- Original Message ----- 
From: "James Frysinger" <[EMAIL PROTECTED]>
To: "U.S. Metric Association" <[EMAIL PROTECTED]>
Sent: Monday, 2003-12-29 12:22
Subject: [USMA:28026] Plextor DVD burner FAQ on storage size


Apropos the use of SI prefixes and the prefixes for binary multiples, this
is
the type of confusion we hope will someday resolve itself, now that a
standard set of prefixes for binary multiples is available. The quote below
comes from Plextor, makers of optical drives. See:
http://www.plextor.com/english/support/faqs/G00051.htm
I came across this while shopping for a DVD burner. Note that they do not
take
their answer to the next level --- 10^9 versus 2^30. It is unclear to me
whether Microsoft et alia consider a "gigabyte" to be 1024^3 bytes or
1000x1024^2 bytes. In the case of 90 mm floppy disks, Microsoft considered a
"megabyte" to be 1000x1024 bytes!

Jim

[quote, edited by me to include missing carets]
Article ID. G00051

Why do I only get about 4.38GB on a DVD disc instead of the 4.7GB advertised
by the vendor?

DVD media has the same capacity conversion confusion suffered by users
trying
to find out the correct capacity of their hard drives. Vendors compute
storage size in a decimal value, while computers compute storage in a binary

value. One megabyte (MB) of hard drive storage is computed by the vendor as
1
x 10^6, or 1,000,000. Computers are binary systems, seeing a megabyte as 1 x
2^20, or 1,048,576 bytes.

In a CD or DVD, a percentage of the disc is taken up by overhead, i;e. link
blocks, track information, reserved areas for video title, etc., and takes
up
some of the user data area , but may not be part of the output data stream.
In the case of a DVD, this is approximately 1 MB.

So a DVD disc advertised by the vendor as 4.7GB (decimal) is displayed by
computer applications as approximately 4.38GB: (4,700,000,000 � 1,048,576) -
1MB = 4.38GB.
[end quote]

-- 
James R. Frysinger
Lifetime Certified Advanced Metrication Specialist
Senior Member, IEEE

http://www.cofc.edu/~frysingj
[EMAIL PROTECTED]
[EMAIL PROTECTED]

Office:
  Physics Lab Manager, Lecturer
  Dept. of Physics and Astronomy
  University/College of Charleston
  66 George Street
  Charleston, SC 29424
  843.953.7644 (phone)
  843.953.4824 (FAX)

Home:
  10 Captiva Row
  Charleston, SC 29407
  843.225.0805

Reply via email to