PaulNM on 27 Mar 2008 17:29:50 -0700

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Re: [PLUG] Disk Transfer Speeds

Stephen Gran wrote:
> On Thu, Mar 27, 2008 at 10:40:36AM -0400, PaulNM said:
>> Not to be pedantic, but it's actually 100Mbit/sec = 11.920929 
>> MBytes/sec.
> Not to be even more pedantic, but it's not 10**8, it's 100 * 1024 * 1024.
> Unless you're a hard drive manufacturer, of course.


>> Bits are decimal while bytes are binary.
> Um, no.  Bits are binary, bytes are 8 bits.

Network transfer speeds measure bits as decimal notation 
(1Kbit=1,000bits), as do most mentions of bitrate.

 From :

"When describing bitrates, binary prefixes have almost never been used 
and SI prefixes are almost always used with the standard, decimal 
meanings, not the old computer-oriented binary meanings. Binary usage 
may occasionally be seen when the unit is the byte/s, and is not typical 
for telecommunication links. Sometimes it is necessary to seek 
clarification of the units used in a particular context."

See also


"Some sources define a megabit to mean 1,048,576 (that is, 220) bits. 
Although the bit is a unit of the binary number system, bits in data 
communications are discrete signal pulses and have historically been 
counted using the decimal number system."

Storage, on the other hand, does tend to measure bits in binary notation 

The whole issue can get very confusing.  Since the thread was about data 
transfer speeds, I went with decimal notation for bits. In retrospect, 
it would probably been more accurate for me to say "powers of 2 / powers 
of 10" instead of binary / decimal.

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