Subject: Re: Python syntax in Lisp and Scheme
From: rpw3@rpw3.org (Rob Warnock)
Date: Fri, 10 Oct 2003 07:26:11 -0500
Newsgroups: comp.lang.python,comp.lang.lisp,comp.lang.scheme
Message-ID: <At6cnenMmq7-OBuiXTWc-w@speakeasy.net>
Andrew Dalke <adalke@mindspring.com> wrote:
+---------------
| (and yes, I know about the lawsuit against disk drive manufacturors
| and their strange definition of "gigabyte"... )
+---------------

Oh, you mean the fact that they use the *STANDARD* international
scientific/engineering notation for powers of 10 instead of the
broken, never-quite-right-except-in-a-few-cases pseudo-binary
powers of 10?!?!?  [Hmmm... Guess you can tell which side of *that*
debate I'm on, eh?]  The "when I write powers of 10 which are 3*N
just *asssume* that I meant powers of 2 which are 10*N" hack simply
fails to work correctly when *some* of the "powers of 10" are *really*
powers of 10. It also fails to work correctly with things that aren't
instrinsically quantized in powers of 2 at all.

Examples: I've had to grab people by the scruff of the neck and push
their faces into the applicable reference texts before they believe me
when I say that gigabit Ethernet really, really *is* 1000000000.0 bits
per second [peak payload, not encoded rate], not 1073741824, and that
64 kb/s DS0 telephone circuits really *are* 64,000.0 bits/sec, not 65536.
[And, yes, 56 kb/s circuits are 56000 bits/sec, not 57344.]

Solution: *Always* use the internationally-recognized binary prefixes
<URL:http://physics.nist.gov/cuu/Units/binary.html> when that's really
what you mean, and leave the old scientific/engineering notation alone,
as pure powers of 10. [Note: The historical notes on that page are well
worth reading.]


-Rob

p.s. If you're hot to file a lawsuit, go after the Infiniband Trade
Association for its repeated claims that 4x IB is "10 Gb/s". It isn't,
it's 8 Gb/s [peak user payload rate, not encoded rate]. Go read the
IBA spec if you don't believe me; it's right there.

-----
Rob Warnock			<rpw3@rpw3.org>
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