Re: is 256 pi's enough?
"(Unrelated aside from confused non-native speaker: shouldn't it be are 256 pis ?)"
referring to: "Is 256 pi's enough ?"
It should be "Are" because Raspberry Pis are countable.
It should be "Pis" because the official Raspberry Pi Foundation style is to capitalise the P.
It should be "Pis" (without apostrophe) because the s is pluralising not possesive nor abbreviating.
It should be "enough?" because in formal english Grammar and (totally unjustified sweeping generalisation alert) in just about every English style-guide, there is no space before a question mark.
So, technically, it should have read "Are 256 Pis enough?"
However, "Pis" just looks wrong and causes cognitive dissonance, so the apostrophe is added in because it looks better. Acronyms are often pluralised with an apostrophe as well because it just looks better (e.g. CD's, DVD's).
I would have written "Are 256 Pi's enough?"