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Comment by bhouston | Hacker News Reader

I think the largest file systems in the world are Amazon's S3, and maybe Glacier. I guess Google's internal system used for YouTube and Gmail probably outrank it but there are no numbers for it. But I doubt that they are in a single address space on a single file system.

So basically we moved away from singular large unified file systems and built swarms of little file systems.

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Indeed. "Cloud" is essentially tons of commodity hardware nodes running a tailored userspace distributed file system application. There now certainly exist cloud services that host well in excess of 2^64 bytes, but they are not hosted on traditional file systems, but an array of those.

I can't certainly blame their choice though, and 16-million terabyte hard drive arrays (the limit of 64-bit addressing) on a large mainframe are really just a few quantum leaps away. Heck, I still vividly recall buying a MASSIVE 40 GB HDD in 2000 - it seemed excessive beyond wildest dreams at the time (and was promptly filled to brim at a LAN party.)

Since, advances in mass storage tech, most importantly the successful commercialization of perpendicular recording in 2005, mean that nowadays 12 TB drives are commercially viable - roughly 1000x the size of a 40 GB drive.

In the next 20 years, petabyte-sized drives might well be available (though almost certainly not based on any form of magnetic recording). Once you hook hundred 50-petabyte drives to a single fileserver, you start closing in on limitations of 64-bit addressing.

Isn't there an XKCD about the limit of flash storage being 3 PB per gallon?

I think you may be referring to an image from this What-If article, where the capacity of a gallon of MicroSD cards is estimated at 1.6PB per gallon:

https://what-if.xkcd.com/31/

It's 12.8PB per gallon now.

A gallon of flash cards is great, but you do have to figure out which one you want after they are delivered. I'm wondering whether there is such a thing as an automated flash card library. I know people have archives of tapes like that.

The thing about flash is that it's cheap and easy to keep it all permanently online. You can get a stack of 2.5 inch SSDs for the same price as microsd cards, and plugging them into a bus takes less space than a tape robot.

When you're looking at the same price for two systems, and one is 100x-1000x faster at the cost of being 'merely' hundreds of TB per gallon instead of a few PB per gallon, nobody is going to bother engineering the latter just to save a few bucks on shipping.

Tape is a lot better at keeping data while in storage though.

Overly pedantic quibble: a quantum of anything is the minimum possible unit. One planck length, time, mass, charge, temperature.

Everybody uses it to mean "big". Oh, language.

But is a "Quantum leap" really equivalent to leaping one planck? Honest question.

I assumed it implied something far 'larger' such as a leap through spacetime...

I believe the term originally applied to electron energy level transitions within an atom, which only vaguely correlates with anything one might call distance.

The interesting thing there was that the electrons existed only at discrete energy levels, and the transition between them appeared instantaneous.

I always assumed that sprang from the tv show with that name.

A quantum leap is a discontinuity, a change that cannot happen gradually.

It typically implies a revolutionary change over evolutionary improvement.

"Quantum leap" is typically interpreted as "big leap" but I believe the true implication is more like "indivisible leap", in line with your quibble. A Turing-complete computer is a "quantum leap" ahead of a non-Turing-complete calculator. A warp drive is a "quantum leap" ahead of a reaction drive. You either have all of it or none of it.

I know who we should ask: Ziggy

I loved that show so much! It was ages after Enterprise came out that I stopped expecting Captain Archer to say "Oh boy!" just before the main title.

Quantum leap is an increase in the units, or “quanta” you use to measure something i.e. MHz to GHz - the term doesn’t relate directly to quantum mechanics

In your example you are using the same units - Hertz, one cycle per second - and adding SI prefixes for million X and billion X.

Yes, but the "quantum" has increased by order of magnitude.

The point is, that the increase in frequency is so large, that using MHz is no longer sensible.

There has been a "quantum leap" in frequency.

In this case, I actually used it purposefully. Hitting on quantum mechanical limits are in part holding us from infinitely increasing the information density on HDDs and SSDs.

The usage in the article is that 64/128 bits is the addressing used for the blocks. A block is 512 bytes. So a 64-bit filesystem would actually be limited to 2^73 bytes = 8192 EiB = 8.6 billion TiB of storage.

No cloud vendor has a billion harddisks, that's for sure.

(The filesystem might only support a maximum file size of 2^64 bytes, but that's nothing to do with the capacity of the storage array)

The article isn't talking about the size of raw disk blocks, better called the sector size. It's talking about ZFS blocks, which are variable in size, defaulting to 128 kB: https://en.wikipedia.org/wiki/ZFS#Variable_block_sizes

ZFS aside, the 512 byte sector isn't even a hard limit at the storage medium level. Disks with 528 byte sectors — and other odd sizes — have been available in the enterprise world for a long time now: https://en.wikipedia.org/wiki/Hard_disk_drive#Market_segment...

HDDs and SSDs with 4 kB sectors dominate the consumer market now: https://en.wikipedia.org/wiki/Advanced_Format

"You know you have a large storage system when you get paged at 1 AM because you only have a few petabytes of storage left." (2010)

https://cloud.google.com/files/storage_architecture_and_chal...

No, they're not a single filesystem, as the papers make clear here and there.

S3/glacier are not filesystems, they are object storage interfaces with labels...

I wonder what backblaze is up to these days...

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