[Year 12 SofDev] SD exam - C8 - Megabyte, Mebibyte?

[Savage, John L]

There’s a disaster waiting to happen. I guess we all remember how unit confusion plunged a Mars rover vehicle into the dust on landing. Luckily no lives were involved, just time, money, carreers and creativity.

Laurie

From: sofdev-bounces at edulists.com.au [mailto:sofdev-bounces at edulists.com.au] On Behalf Of Robert Hind
Sent: Monday, 17 November 2014 6:32 PM
To: Year 12 Software Development Teachers' Mailing List
Subject: Re: [Year 12 SofDev] SD exam - C8 - Megabyte, Mebibyte?

Thanks Mark for the update to my knowledge - re the Mebibyte.

I am sufficiently old that the traditional definition of Megabyte as 2^20 bytes is the one that sticks in my mind. After all modern computers are based on binary rather than decimal arithmetic. Have seen the IEC definition referred to as "Japanese Megabyte" in some forums.

Robert Hind
Retired
Ex Traralgon and Ashwood
----- Original Message -----
From: Mark<mailto:mark at vceit.com>
To: Year 12 Software Development Teachers' Mailing List<mailto:sofdev at edulists.com.au>
Sent: Monday, November 17, 2014 5:05 PM
Subject: [Year 12 SofDev] SD exam - C8 - Megabyte, Mebibyte?

Hello, commuters.

In the 2014 SD exam, section C, Q8, an innocuous question is asked about 'megabytes'.  I wonder if the question realises the quandary it creates...

The current 'official' IEC (International Electrotechnical Commission) definition of a 'megabyte' is exactly 1,000,000 bytes, so the answer to C8 is 6.0 and 20.0 respectively.

But using the traditional (and industry standard) interpretation of a 'megabyte' - now charmingly known as a Mebibyte (MiB) - as being 1,048,576 bytes results in answers of 5.7 and 19.0.

Paula: what is VCAA's official stance on the definition of kilo, mega etc in VCE IT exams?

Will the markers accept '19' as an answer to C8 part 2?

P.S. According to urbandictionary.com<http://www.urbandictionary.com/define.php?term=Mebibyte>, a Mebibyte is "A new, weird and unnecessary unit of data capacity, created by some idiots of IEC and aggressively advertised on Wikipedia. 1 Mebibyte equals 0.9765625 Megabytes and serves no purpose other than confusing people".

Urbandictionary.com is right in its sentiment, but wrong in detail. A new 'megabyte' is 1,000,000 bytes. The old megabyte is now called a Mebibyte and is 1,048,576 bytes. That's what's confusing: IEC has redefined an old, accepted unit, introduced a new unit that no-one wants to use, and now chaos reigns because no-one now knows what someone means when they say "megabyte".

Let the fun begin.

--

Mark Kelly
mark AT vceit DOT com
http://vceit.com

I love the sound of people's voices after they stop talking.

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