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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.
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."
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.
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.