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Comment by wkjagt | Hacker News Reader

Depending on if they are old enough to remember floppy disks, tell them the tiny card holds as much information as almost 1.4 million 3.5 inch floppy disks (assuming 1.44mb each). If you pile those up, it would be about 4.5 km high. Or if you take the 720kb kind, your pile would be as high as Mount Everest.

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I am old enough to have used 5 1/4 inches floppies on PCs running MS-DOS, 3" microdrives on ZX Spectrum 3+, and tapes on Timex 2068.

One of my teachers broke the compilation record of compilation submissions per day, on the computing center, with punched cards.

On my first trip to a computing center of the post office during high school, they still used punched tape.

The modern SD cards are indeed a wonder.

Yeah this is the corollary to "use boring technology" - at some point, jump.

They could put the capacity of every 3.5" floppy ever made in a suitcase full of microSD cards.

A wild guess of 3.5" floppy production is 30B. So you need 21,428 2TB micro SD cards. A 15mm x 11mm x 1mm you need 3 1/2 liters.

The bandwidth of a station wagon hurtling down the highway grows every year.

Sneakernet remains undefeated. https://what-if.xkcd.com/31/

>> "A solid-state laptop drive weighs about 78 grams and can hold up to a terabyte."

Amazing how we went from 1TB 2.5 inch drives to 8TB m.2 drives and 2TB microSD cards in 11 years. And it would be more like $7k in 4TB drives than $130k. Put $130k of modern drives in the same shoebox and you're probably into the petabyte range. Go to the then-top of the line microSD milk jug and it's getting up there with these 2TB cards.

I had estimated 10^11.

This seems like it would work, but the average person has no idea how high mount Everest is. My favorite way of explaining it is when I was looking at Mount Olympus from the beach, and said "you see the mountain? If you stack two more Olympuses on top of that, it still wouldn't reach Everest".

Another way: taking the 720kb variety floppy, if you lay them side by side it would form a line of 250km in length. Or in other words: driving at highway speed, it would take 2 and a half hours to drive by all the floppies it would take to store what one of these new micro SD card can hold.

Oh I love that!

Then again you never look at Mt Everest from sea level.

Technically true, but the base of Mt Everest is at 5100 meters, which makes it a lot less impressive. The entirely Himalayan range is sitting two vertical miles above sea level.

Okay, I'll byte. Imagine a game of Tetris where each block is a byte of data. With a 2TB card, you'd be playing until the heat death of the universe – and still not see the Game Over screen.

"I could have a bodycam record everything that happens to me for a whole month, 24/7, in high-definition and store it on something smaller than my fingernail."

HD (1080p) video @ 30fps is from 130-149MB/sec

2TB / 149MB = 13,422 minutes == 223.7 hours == 9.32 days

I'm being facetious of course but I was surprised by just how much storage space I needed to record security cameras. I have a mix of 4k & HD, and 10tb doesn't even get me a month of 24/7.

YouTube’s 1080p is 5 megabits per second, not 130 megabytes per second.

So 2TB lasts 37 days, meaning blowski is right.

Of course powering that bodycam will be a different matter.

Of course this is all academic: the file size depends on the codec, ie how much you want to trade power for space. YT/Netflix/etc obviously trade for file size very well. But a body-worn device isn't as capable.

Take the Axon Body 2 as an example, the gold standard for police bodycams. According to its specs [0] it'll record 12 hours of 1080p video on its 64GB internal storage.

So using H.264 it produces 64gb/12hr == 5.333 (repeating of course) GB/hr, making 2TB / 5.333GB == 375 hours, or about 15.625 days

[0] https://s3-us-west-2.amazonaws.com/cms-nppgov.resources/app/...

Video compression. Another separate modern marvel of mathematics.

Not sure what security cameras you’re using, but mine all use H.264 1080p compressed streams. I get about 15 days worth on a 2TB spinning rust across 6 cameras.

Even going by your own numbers, you almost certainly are using compression too. 9.32 days on 2TB does not get you a month on 10TB if you “have a mix of 4K & HD”.

Indeed. I use Unifi cams, 3x4k & 5x1080p, they use h.264. My system's current estimate is 19d 20h 37m of recording.

I really wish they enabled h265

What cameras are you using?

Or tell them if you wrote 0s and 1s on a paper tape, for 2TB of data, you would need a tape as long as the distance between the Earth and the sun. (9mm or a third of an inch per digit)

On the other hand, those discs would barely fill a 40-foot container. I think that's quite close to what people would intuitively expect.

Holy shit that’s a great way of putting it.

I’m not double checking the math but that’s insane, 1.4 million, insane.

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