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How Heavy Is a Petabyte?
Jon Morgan writes "Whilst heaving around numerous data storage systems to sell (they weigh A LOT!), we got to wondering: How heavy is a Petabyte of data storage? Our best guess is 365KG, which is 6 million times lighter than in 1980! But is there a lighter way to store a Petabyte?"
...weighs something like 300mg/card. That's 48GB/gram, or a bit over 20g/TB, or 20Kg/PB.
I've seen stats that all the books ever written by mankind add up to 50 PB of data storage. Presumable unZipped :)
http://www.object-matrix.com/
According the Library of Congress' website they have approximately 32 million books. A bit of googling turned up that an average book weight about 12 ounces. So, 32 million * 12 ounces = 10,886,216.9 kilograms
A common misconception, and just saying it on Slashdot doesn't make it true. Clouds weigh more than elephants - much more. In fact, you can learn the weight of clouds in elephant units here.
Not only that, but clouds are usually darker than the air around them.
"It's the height of ridiculousness to say for those 9 lines you get hundreds of millions."
Problem is those methods of dropping the weight, also increase the cost (TFA assesses both).
My problem with the assessment however, becomes even more glaringly obvious when you look at the micro SD proposal in the grandparent. If you are going to have a single SD card reader and plug these cards in as needed, the weight estimate is ok. If however all 1 PB of data must be immediately available to your software, the weight gos up dramatically.
In the case of 3.5" SATA HDDs, that weight/cost should include a storage system that renders all the data available at the same time. 140 Lbs for 48 Hard drives is reasonable.
Depending on your RAID Level, 1,500 Lbs per petabyte is closer to reality. 1,700 Lbs to 2,000 Lbs per petabyte if you add the rack to the equation.
BTW: Doing something sane, like RAID, instead of JBOD or RAID 0, will increase that mass somewhat.
--= Isn't it surprising how badly I spell ?
Air also weights more than elephants.
In fact, every square meter of the world has 2 elephants of air on top of them.
So "missconception" my ass.
HI O WISE PRINCE. WHT TOOK U SO DAM LONG?
For example, it seems to me like a "full" drive seems to physically weigh more than a blank one, sort of like a full battery is noticeably heavier than an empty one.
Wrong on both counts. A "full" magnetic hard drive platter just has its magnetic domains aligned in a certain pattern.
Those domains are physically there whether they are used for data storage or not. So the weight will be indentical.
A battery does indeed become lighter when "emptied" - according to E = mc^2 and the energy that came out of it.
However, this is way, way, way under anything you would be able to notice.
An AA alkaline battery can deliver about 10000 Joules (http://www.allaboutbatteries.com/Energy-tables.html) - so
a discharged (= "empty") AA alkaline will weigh m = E/c^2 or roughly 10^-10 grams less than a charged one.
That's 0.1 nanograms. About 100 human skin cells. No, you won't notice that.
I've seen stats that all the books ever written by mankind add up to 50 PB of data storage. Presumable unZipped :)
You've seen ESTIMATES.
These posts express my own personal views, not those of my employer
Insightful? Assuming you can perfectly remember 1 byte per second, you'd be memorizing for over 100 million years. The human brain is great and all that, but no way are you going to store that much data while being able to reproduce it later.
That was my dissertation topic, conventional systems require ~kT per bit (k is the Boltzmann constant = 1.3806503 Ã-- 10-23 m2 kg s-2 K-1 and T is the temperature of the gate in Kelvin) for each read. Quantum systems can access well below that by various trickery (single photon optical computers can reduce this by a thousandfold). In theory a individual photon can hold huge amounts of data in it's state vector before collapse. The trick is making a measurement on enough of these photons to extract the info you need while overcoming shot noise.
A common misconception. Weight is not mass.
Air also has mass, not much different from the mass of cloud (which is mostly air).
51.2 LoC's
Assuming LoC is still = 20TB
"The problem with socialism is eventually you run out of other people's money" - Thatcher.
Not if you do it reversibly.
Here's the one that'll really get you:
A pound of feathers weighs more than a pound of gold.
Well, a rough check shows that each base pair (and backbone) weighs about 614amu, which gives a weight of 10^-21 grams for 2 bits. So, pure DNA weighs about a 4ug per petabyte, supposing my calculations are correct.
However, that's hardly fair. The density of bits is _far_ from the density of the actual storage. After all, a hard disk uses only extremely small regions (probably only a few million amu) on the surface of a disk. However, the motors, the case, and even the disk (substrate) itself are orders of magnitude heavier than the bits themselves. I'd be rather surprised if the actual storage was much more than a couple grams.
The point is, of course, that there are all kinds of ways to store data, but when it comes down to weight, the control mechanisms are what matters. For this reason it's extremely unlikely that DNA will _ever_ be used as storage, except if we start making bio-computers.
Also, for what it's worth, the human genome only stores about 770MB, only a bit more than a CD.
That is, of course, due to the fact that a Troy pound (used for gold) measures a lower weight than an avoirdupois pound.
Not a sentence!
digg isn't silly; they're entirely serious when they give answers that are life-endangeringly wrong :-S
I mod down anyone who says "I will be modded down for this", regardless of the rest of their comment
unfortunately, the practicality of removing the BTU from a book is more effort than it's worth? Have you ever tried to burn a book? It's actually not as trivial as one would think.