Weekly Classic Computer Trivia Question (20141205)

[Mouse]

> For one terabyte, the difference is close to 10 gigabytes...
> (For one meg, the difference is 48K).

The rough-approximation estimates I usually use are 2.5%, 5%, 7%, 10%
for K, M, G, T.  (The precise values depend on whether you're talking
about the amount by which the metric values fall short of the binary
values or the amount by which the binary values exceed the metric
values.  But even for TB that's 9.95+% vs 9.05+%, not a huge
difference.)

>> Actually, the notes in the ads were added later due to litigious
>> bastards and other chancers claiming that they believed it to mean
>> powers-of-two and making a nuisance of themselves in court.

Such a claim would not have been plausible enough to get anything but a
summary judgement for the defendant, with costs, if there hadn't, at
the time, been well-established power-of-two meanings.

And at least one manufacturer outright lied to me about it.  Back when
Zip disks came out, they were sold as 100MB.  They were actually 96MB
(bang on the nose, too - 196608 sectors, not 96.026+MB or any such).  I
had occasion to call iOmega for something else related to Zip disks and
asked them where the other 4MB went, not because I didn't know but
because I was curious what they'd say.

They told me the 100MB was unformatted capacity.  Even then, 4%
formatting overhead seemed unrealistically low to me, and a techie who
once worked for them and knew the low-level details later confirmed to
me that the formatting overhead was more like 20 to 30 percent.

I didn't call them on it; I couldn't see any good result from doing
that.  But that they had the lie prepared and had primed their
front-line phone people with it made it clear to me that (a) it _was_ a
lie and (b) they knew the truth would not go over well.

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