

How much is a Petabyte? - quizbiz
http://mozy.com/blog/wp-content/uploads/2009/07/whatsapetabyte.gif

======
sp332
Kinda cool, but the second one (with the concentric circles) is obviously a
bad graph. The radii of the circles are proportional, so the ratios of the
areas (apparent size) are off by a factor of pi.

~~~
tomerico
Pi doesn't affects the ratio. However - the ratio of the areas is the square
of the ratio of the radiuses, and that is the mistake in the graph.

~~~
sp332
(Sigh), yeah so in this case they were off by a factor of 3, not pi. I was
close :)

------
fserb
Sorry for being grumpy, but how does it help to say that "1 petabyte = 20
million four-drawer filling cabinets filled with text"? Changing one huge
number (1pb) with another (20M) doesn't add much to the overall
understandability. The other examples are similar in nature. They're either
comparisons with other giant magnitudes (10B facebook photos) or comparisons
with things we have no fucking clue of how big they really are (HD
manufactured in 1995, google's processed data).

"1 petabyte is a lot of data". Oh rly?

~~~
scott_s
It appeals to our experience with everyday things. We have a mental model for
how much information is on a piece of paper, in a book, or in a second of
video.

~~~
jdrock
I don't think anyone can properly visualize 20 million of anything.

~~~
scott_s
No, we can't. But "20 million cabinets of text" has more meaning to us than
10^15 bytes.

~~~
ableal
That's what - one Empire State Building worth of cabinets ?

100 floors * 100 offices/floor * 20 cabinets/office = 200k cabinets ...

Hmm. Off by a couple of orders of magnitude. More buildings or squeeze until
the pips squeak.

~~~
ableal
Seems the E.S.B. volume is about 1 million cubic meters and a 4 drawer cabinet
is about 0.4 cubic meters. So, ten buildings filled solid.

Incidentally, data via Google. Wolfram Alfa pouted on the building query.

(Yes, I'm easily amused. Or distracted: <http://xkcd.com/356/>)

------
jmillikin
Looks like they forgot to show it to a geek before publishing. Not only did
they claim a TB is 1024 GB, but they did so just after saying a TB is 1000 GB.

Also: interesting to note that the graph of dollars per GB has continued to
decrease rapidly. Consumer-level drives are currently at about $0.08 per GB.

~~~
markbao
I don't see that anywhere except for the part where they talk about the hard
drive holding 1000GB. That's the standard way of measuring hard drive space
for most drive manufacturers.

~~~
jmillikin
About halfway through they state 1 TB = 1000 GB, which is correct.

Further down, they have comparisons of relative size from MB to PB, where they
incorrectly use binary units.

~~~
calcnerd256
It is correct to use binary units unless you are selling hardware. We say
TeraByte, but we mean TibiByte.

------
charlesju
I'm calling bullshit on the last stat. Where does he source this from?

~~~
mitchellh
I agree. This is ignoring the fact that there are hundreds of languages we
don't know about and probably millions of texts unaccounted for lost through
the ages.

~~~
wlievens
... which are all probably not relevant in scale.

It's like the "how many humans ever lived?" question. People immediately start
discussing about the definition of a "human being", homo whatever. I say it's
pretty much irrelevant to the final number.

------
Andys
I don't feel like a petabyte is a lot of data anymore.

Sun's Thumper is a 4RU cabinet containing 48 disks. If you had a rack full (10
thumpers: 40 rack units) with 2TB disks, that is 1 raw/unformatted petabyte.

~~~
scorpioxy
Indeed. I still remember when buying a 3GB harddisk was a big deal and thought
that you could never fill it. And now I need more than 300GB just for my
laptop.

Now you can get a 1TB one for less than a $100.

------
yycom
A lot of dogs and cats

------
TweedHeads
Your whole life recorded on video.

That much.

