Binary versus Decimal prefixes



#24

While thumbing through an NIST document, I came across the following:

"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 = 2^10 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."

While it seems a good idea in theory, how the hell is this going to stick? We've been saying "kilobytes" for 30 years and we know that is 1024...

I'm not a computer dude (far from it). If you are, what do you think of this?


Edited: 21 Apr 2013, 9:01 p.m.


#25

Personally, I like reducing the ambiguity (although I don't like the inconsistency that kibi is abbreviated Ki, whereas kilo is abbreviated k (then again, I get that it's resolving the lowercase less than 10^0, uppercase greater than 10^0 inconsistency in SI)), although I don't like that it came to it.

Personally, I've adopted the binary prefixes (except I use ki instead of Ki). And, there is no such thing as a 1.44 MB or 1.44 MiB floppy disk - they're 1,474,560 B, 1440 kiB, 1.4063 MiB, or 1.47456 MB. 1.44 only works if you combine prefixes, as in, 1.44 kkiB.

#26

I think the context makes it clear enough. For example, if you say kilobytes, it it assumed you mean sets of 1024 bytes, whereas if you say kilohms, it is assumed you mean sets of a thousand ohms.


#27

+1

d:-)

#28

Clear enough by context? So if you say gigabytes, are you talking about units of 1,000,000,000 bytes, or 1,073,741,824 bytes?


#29

Quote:
So if you say gigabytes, are you talking about units of 1,000,000,000 bytes, or 1,073,741,824 bytes?

As far as I obeserved in the real world 1kB = 1024 Bytes, 1MB = 1000kB, 1GB = 1000MB = 1 024 000 000 Bytes, 1TB = 1000GB, etc. Not fully coherent, but far better than thumbs and feet.

d:-)


#30

It depends on the sub-context, though. When you're using

When you're talking about hard drive capacity (and network speeds - 1 gigabit per second is, IIRC, 1,000,000,000 bits per second):

1 kB = 1000 B
1 MB = 1000 kB
1 GB = 1000 MB
1 TB = 1000 GB

When you're talking about solid state storage, bus speeds, RAM, really anything that ISN'T hard drives or networks:

1 kB = 1024 B
1 MB = 1024 kB
1 GB = 1024 MB
1 TB = 1024 GB

So, there's tons of ambiguity.


#31

I gotta agree on this one. Computer-related terminology should remain consistent with its binary-based foundations. Thus, I whole-heartedly concur that its kilo, mega, giga, etc. prefixes should remain in agreement with its binary meanings. In both, hardware drives and software, yes, since they are also computer related, these too should retain the binary relationships.

Although, in terms of clock and processor speed, the K, M and G prefixes should adhere to their decimal/base ten underpinnings (i.e. KHz, MHz, GHz) because these technologies of mechanics and electronics have always been measured on the decimal/base 10 scale.


Edited: 26 Apr 2013, 2:35 p.m.


#32

Quote:
Although, in terms of clock and processor speed, the K, M and G prefixes should adhere to their decimal/base ten underpinnings (i.e. KHz, MHz, GHz) because these technologies of mechanics and electronics have always been measured on the decimal/base 10 scale.

FYI, it's kHz still with a lower case prefix k. Please look here.

d:-I


#33

I remember once I got a penalty in one otherwise perfect exam because the professor thought I had written KVA instead of kVA. Apparently the k's upper arm did not look small enough to him. Oh, well...

#34

On another forum, I keep seeing mhz or mHz, when they actually meant MHz, a billion times as many cycles per second as they said. Our production people kept labeling capacitors with MFD, and I explained that that would be an automobile-sized capacitor, and if they couldn't write the lower-case Greek letter mu for "micro," then please make it a low-case "u" and write 100uF for example, not one hundred megafarad!


#35

I remember decades ago seeing a press release for a new modem chip suitable for laptops because of its power consumption. It was listed as using some number of MW (megawatts) instead of mW (milliwatts). Not the kind of thing I'd want on my lap, even in a Colorado winter.


#36

Quote:
I remember decades ago seeing a press release for a new modem chip suitable for laptops because of its power consumption. It was listed as using some number of MW (megawatts) instead of mW (milliwatts). Not the kind of thing I'd want on my lap, even in a Colorado winter.

If you really want to warm up a room, borrow the 5 TW laser pointer that the HHC 2009 website claims was among the audiovisual supplies for the presenters: http://hhuc.us/2009/talk.htm This year they only have a puny 200 mW laser pointer.

#37

Quote:
borrow the 5 TW laser pointer

Do you think I can borrow the battery to power my Delorean ? :)
#38

I take it back. Upon further recollection, the press release actually said "megawatts" and not just "MW." One of the hardware types did some research and determined that Hoover Dam could power a number of these, a number in the single digits.

#39

Thanks for the clarification.

#40

The context would be clear except for marketing people. I believe disk sizes are always quoted using powers of 10 instead of powers of 2 now since the power of 10 number is bigger.


#41

Perhaps that explains why I keep feeling ripped off. I alway end up with 900 something in my 1TB drives :-(

#42

Good morning!

Quote:
...Although these prefixes are not part of the SI, they should be used ...

As long as half of the world still uses miles and feet and inches and gallons and pounds (which have never been part of SI and were supposed to be made obsolete 150 years ago) I think we need not worry about prefixes that only "should" be used ;-)

BTW: I have never before heard of these binary prefixes (and I have been working in IT for quite some time!) so we probably can suppose that the general public hasen't heard of them either. It would generate quite some confusion if they were introduced now!


#43

There are only two countries that officially use feet and inches and gallons and pounds: the USA and Liberia. Additionally Berma/Myanmar uses their own quite different system. The rest of the world is committed to the metric system. However, much of the world is well behind Europe in this and needs another hundred or two years to full convert.

e.g. Australia has officially been metric since 1970, however I can purchase 8' x 1200mm wall panels here and I learned both system at school in the 1970s.


- Pauli

#44

How about we just repeat the unit to signify magnitude? 2^(10*(n-1))

So 1 bytebyte = 1024 bytes, 1 bytebytebyte = 1048576 bytes, etc.


#45

Quote:
How about we just repeat the unit to signify magnitude? 2^(10*(n-1))

So 1 bytebyte = 1024 bytes, 1 bytebytebyte = 1048576 bytes, etc.


This is a good idea. To me, using metric prefixes means powers of 10.

#46

Like "two to two to Toulouse"? Language was once invented for better understanding - long time before some languages arose.

d;-/


Possibly Related Threads...
Thread Author Replies Views Last Post
  HP-Prime_CAS versus MAPLE_CAS CompSystems 0 103 08-18-2013, 11:58 PM
Last Post: CompSystems
  Decimal/Binary Conversions for the HP 39gii - 3/16/2013 Eddie W. Shore 0 140 03-16-2013, 04:30 PM
Last Post: Eddie W. Shore
  BCD, Binary, ...Binary Coded Duodecimal? mpi 7 324 02-20-2013, 04:28 PM
Last Post: Paul Dale
  33s Decimal Point Matt Agajanian 4 239 11-06-2012, 09:20 PM
Last Post: Matt Agajanian
  Obtaining More Decimal Digits (50g) Eddie W. Shore 3 241 09-13-2012, 05:38 PM
Last Post: Gilles Carpentier
  HP-35A/21 D.MS<-->Decimal degrees routines Matt Agajanian 9 401 03-29-2012, 11:03 AM
Last Post: Matt Agajanian
  Merged prefixes on the 65 Matt Agajanian 3 116 03-12-2012, 12:49 AM
Last Post: Matt Agajanian
  HP 28S saw 36V versus 4.5V, damage and repair? Joshua Keena 4 162 09-10-2011, 10:58 PM
Last Post: Joshua Keena
  HP 15c LE - U.S. versus European version Michael Kussmaul 16 479 09-09-2011, 12:29 PM
Last Post: Walter B
  A speed comparison of the 41CL versus the 41CX (and my first YOUTUBE video) Geoff Quickfall 6 234 08-08-2011, 02:33 AM
Last Post: Ángel Martin

Forum Jump: