Date   : Mon, 27 Jul 2009 23:43:46 +0100
From   : afra@... (Phill Harvey-Smith)
Subject: Units of memory, Was: Master Ethernet upgrade

Jonathan Graham Harston wrote:
>> Message-ID: <4A6C801B.4020301@...>
> Technical terminology embedded in computing science for over 60
> years. Are you going to go back in time and reprogram the BBC to
> ensure it starts up saying "32.768KB" ?
>  
> One "1K" as a unit of memory size - as opposed to "1KB" - always
> was, always is, and always will be 2 ^ 10, and 2 ^ 10 always was,
> always is, and always will be 1024.

Whilst I generally agree with you, when talkig about computer memory 
disk etc, it makes much more sense to talk in something that is a power 
of 2 e.g. 1K=1024, 1M=1024x1024 etc, this is what I use :)

However there are those that would argue that in SI, K=kilo=1000, and 
strictly speaking they would be correct. Or was that what you where 
getting at with the 1K/1KB destiction ?

> As long as you define your terminology before you use it, you can
> use furlong-firkin-fortnight[1] if you really want to.
>  
> [1] Standard use in sheddie circles. Be back in a millifortnight.

I once had an argument with a friend at school, where I argued that you 
needent used 1 and 0 to represent binary, you could use any pair of 
symbols as long as you defined what they meant, X and Y for example so 
say $5A would be XYXYYXYX :) he wouldn't have it and isisted that it had 
to be 0 and 1.

> Pete Turnbull wrote:
>> On 25/07/2009 16:40, Jonathan Graham Harston wrote:
>>> No, 'cos you can only have one multiplier prefix. It should have
>>> had a ;) as memory units never take prefixes, you use a different
>>> unit.
>> That's not true either.  Using several multipliers is quite common in
>> electronics and physics, and perfectly acceptable in the SI system.
>  
> Are you sure? Why would you use mmA when there's a perfectly usable
> uA?

I believe from what I have read that was common in the USA at one point.

> Digging out my Tennent's, p37 says: "To obtain multiples and
> submultiples of units, //a// standard prefix is used, as shown
> below" (my emphasis)
>  
> and
>  
> "Quantities should be expressed as a value between 1 and 1000 with
> an appropriate multiplier". eg, 47000W should be expressed as 47kW,
> 0.0000022s should be expressed as 2.2us.

Humm tell that to battery manfacturers that insist on quoting 
rechargables as 2500mAh, instead of 2.5Ah, but that I think is psycology 
coming into play, people[1] think it's better because the number is 
bigger, the fact is that the two quantities are equivelent, I guess the 
tought is that if Manufacturer A quotes 2.5Ah, and manufacture B quotes 
2400mAh, then people will go for B because it *SOUNDS* bigger.

Likewise ?99.99 etc.

To drag things a little back on topic compare the BBC and the Spectrum, 
going on clock speed the Spectrum should be better as it has a higher 
clock, approx 3.5MHz as opposed to 2MHz, but anyone has actually used 
both machines will tell you which is faster for most things...then again 
  if you want games you may be better off with the Spectrum anyway :)

[1] The majority of people who may not understand or bother to 
understand what the units mean.

All IMHO of course.

Cheers.

Phill.



-- 
Phill Harvey-Smith, Programmer, Hardware hacker, and general eccentric !

"You can twist perceptions, but reality won't budge" -- Rush.