1000 or 1024 for KB, MB etc


#1

Hello,

Just starting Unit 2 and in general things are going well.

My question is in the AP exam will questions generally use the approximation rule of thumb for KB, MB, GB etc? Or the precise measurement 1024?

I prefer teaching the 1024 (especially as following on from Unit 1 ‘Binary’ students already have some knowledge of this). However I notice in what I have seen of Unit 2 most questions/answers use the approximation of 1000 (EG: 1000KB is a MB etc)


#2

I don’t think I have ever seen anything in any of the sample exams where the 1000/1024 would trip up students. I too prefer to talk in terms of 1024 to my students. Has anyone else seen anything form the College Board where that would make a difference?


#3

You might note that even in the support document linked from Stanford CS 101, there’s a note at the very bottom of the document about this bit of ‘sloppy vocabulary’ and there being a general tolerance for ‘rounding error’ the difference between powers of 10 and powers of 2. I like precision of numbers AND language, but the general population (outside APCSP) is not easily diverted from over generalized (abstracted?) approximations. Our job is to inform our CS students about this exact topic and increase their awareness of it. As long as the actual College Board test questions are specific (or forgiving?), I think we’ll all be fine…